Car Audio tips from the beginner to advanced installer or advanced competitor .We also rent small DJ size systems in the Los Angeles, Sandiego area and sell voicecoils or prototype parts and basshorns. We also recone big woofers and fix amplifiers!
|We have been getting so many customer requests for additional car
stereo information we have made our NEW BOOK: "HIGH SOUND PRESSURE LEVEL SPL, DB AND STEREO'S"
©2014 William Hamby which has much more info and and over 120 pages of very technical secrets and LOTS AND LOTS of sound pressure
dB formulas, calculations, and predictions. Box types, and speaker types totally covered. A total must have for dB competitions or engineers, it's only $49 + 6 shipping USA, send to paypal.com to firstname.lastname@example.org.
we will add more and more information slowly as time permits:last update 2016 aug 24. EMAIL or CAll for instant answers. We are directly involved with all these;
Worlds Loudest Car Stereo Champions;2015, 2014,2013, 2012, 2011, 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002, 2001, 2000, 1996
Click on any car stereo topic under this serious car audio competitor photo;
Use a Sound Meter:
If you are serious about car stereo sound, use, borrow, or buy a sound level meter.
A sound meter can save you lots of money.
The reason for a meter is because once you have your system done, it may take a big
increase in amplifier power to see a slight 1 to 3 db increase in sound pressure level. think how much
money it will take to double the number of amplifiers you have! Much cheaper to buy a sound meter and re-tune and design your system better, noticing what changes in design makes your db level go higher with the use of a sound meter.
Don't buy junk:Please do yourself a favor... don't buy junk or junk brands!
Do you ever go down the isles at the supermarket, and think to yourself "I wish they had a toothache or headache i could buy because i want to buy one?" NO you don't, no one wants to buy a toothache, well many times a junk brand piece of electronics are just like a toothache. So don't buy one! Junk brands means you or the neighborhood stereo shop Circuit City guys have never heard of it, or never heard it with your own ears, or the ears of a friend of yours. Just because something is low price does not mean it is junk! Sears, Walmart and many car parts stores have low price brands. Low price brands are better than the junk brands. For many people the low price brands are good enough, it works and sounds pretty good. Junk brands are like buying a toothache or a really bad headache. Stolen, lost, or dirty beat up radios from the swap meet, neighborhood parolee or crystal-meth freak with torn or missing wires out the back is also considered junk.
reason 1: junk usually costs almost the same as the good stuff or at least 80% of the price, which usually means if you just save your money for another month or so you can get the name brand or good stuff. I know not all of us are millionaires, and we got kids to support, so just buy the good stuff one piece of the system at a time every 3 or 4 months or so, time will go by and sooner than you think your going to have a really good system.
reason 2: Junk stuff breaks alot faster than the name brand stuff. If your impatient and cant wait another month your going to suffer when that junk brand you bought because you were in a hurry, BREAKS. And yes it will break and break soon. Oh ya, your going to be without a system until you can save up for the good name stuff, and chances are that is going to be alot longer than 1 month you should have waited to save for the good stuff anyway.
reason 3: If economic times get either bad(sell) or good (you want to upgrade your system), you will want to sell your system. If it is the good stuff you can sell it used for 35 % to 70 % of what you paid for it new, if it is the junk brand you probably will not even get 10 % to 20 % of what you paid even if your lucky, the reality is you probably won't even be able to sell it. It will just wind up sitting around your closet collecting dust.
reason 4. Sound quality is really not as good as the name brand stuff.
reason 5. No or superweak guarantee with the junk brand.
reason 6. Usually junk brand companies use junk brand ingredients (parts) to make their junk brand equipment. If your planning to get a hamberger, you don't go pull up to a Mcdonalds then go to the back dumpster and whip out a hamburger, it is the junk, for whatever reason Mcdonalds decided it is not up to their quality standards so the put it in the dumpster, well big factories do the same thing. Junk factories get the dumpster parts to make the junk brand stuff.
reason 7. The junk brand stuff leaves out 1 critical feature or ability that the good brand has in order to cut the 20% off of the good brand price. An annoying critical feature left out is secondary amplification on the C.D. deck units, in other words the decks push out a pitiful 1 or 2 watts RMS instead of the standard 17 to 25 RMS. They do this by not putting in secondary transistor amplifiers to cut the price. Another feature that is cut out is the fast forward on the CD play. Another feature you cant see is the radio clarity or the ability to pull in far radio stations, or the ability to lock in on 1 station at a time. No ipod or aux. inputs. No memory(s) or shuts off randomly.
reason 8. Joe 6 pack tells you he has installed a million car stereo systems, but really he just cut 2 out of
an ex-girlfiend's car with a pocket knife. He tries to install your system and surprise surprise he does something wrong and blows something up... Name brand = usually will allow a return and gives you a new one(or repairs for free), junk brand= sorry,
was not installed properly by an "authorized" dealer, no money, no return, now you own just an expensive
BROKEN piece of junk. Joe 6 pack looks at you and says "you should'nt bought a piece of junk...well, I'm going to the store to get some more beer".
Car Batteries:Car batteries must be given tremendous respect.
Did you know when you start your car, for a microsecond every ATOM on earth "feels" the electromagnet force!
They are very powerful devises. A normal 12 volt car battery has about 10,000 watts of available 1 second power, or about 50 to 100 AMPERES for about 20 to 60 minutes.
Converted to more understandable units, the energy in 1 battery could lift 310 TONS 1 foot off the ground!This is about 620,000 foot pounds of energy!
If it were possible, to get a battery to separate all it's positive and negative charges it would require a force of about 80,000,000,000,000,000 TONS!
A car battery is called 12 volts but is actually normally
about 12.62 volts, a D.C. voltage summary can be approximated like this:
The true power flow from a car battery is not from the voltage however, it is from the AMPERAGE(the total flow of electrons). A normal car battery has about 800 AMPERES of instant current dumping ability. Taking the VOLTAGE(13) divided by the AMPERES(800) gives the OHMS (0.01625 Ohms), a battery has extremely low resistance, hence the high power dumping ability, also do not play with batteries with wet hands or in the rain!
1 car starting engine battery is good for about 4000 watts RMS = 200 amperes constant. 1 solo alone battery is good for about 5000 watts RMS= 250 amperes constant. So about 1 ampere is 20 watts in real life amplifier battery testing.
Many people who compete in decibel contest use (two) 8 volt golf cart batteries in series. This gives an apparent voltage of 16 volts to each amplifier, but actually closer to 17.7 to 19.1 volts. You must find out if your amplifier is capable of this because many amplifiers cook and die at that high of an input voltage! Most will take 14.4 volts. Some use R.V. batteries. Some upgrade the alternator and or the voltage regulator of there car/ truck. Some use "batcaps" that have the ability to instantly dump amperage faster than batteries. If you need more power for your amplifiers, some people put another battery inside their loudspeaker box. If you want to do this just connect the battery to the engine battery, then using fat wire connect the amplifier to the inside the box battery, and always RED positive to RED positive and BLACK negative to BLACK negative wire(i.e. wire in parallel).You must brace the inside of the box with 2 by 4's so the battery does not slide around when you drive your car. Also put a huge fuse in between both batteries, like 100 AMPERE. NEVER put a battery inside a car where the people sit unless it is inside a very strong enclosed container (like a speaker box) because they can explode!
Please give your battery fat, fat, fat wires. the fattest you can afford. they dont have to be fancy or name brand just fat, like a garden hose!!! 1/0 or 00 gauge, or you r amplifiers will be weak.
wire wire wire. FAT FAT FAT!!!! all your electronic wires should be FAT like a garden hose except the factory deck wires because they are made specifically for the deck and decks only need about 100 watts and 3 amperes of electricity. wire is rated in GAUGE numbers.the bigger the number the smaller the wire, so just remember ita backward like that. for normal powercords in your house that size wire is 18 gauge, 12 is thicker and carries more electricity better.big amps need at least 4 gauge that is like your pinky finger in thickness. bigger amps need 0 gauge which is FAT like your thumb, if you keep adding zero the wire is thicker like 000 gauge this is also written as 0/3 or 3/0 gauge , this is fat like a garden hose. the wire distance should be short.
Dont be annoying!:Alot of people dont think its cool to be BOOMING LOUDLY near your own house, or in the middle of the night, remember alot of people sleep at night or even nap in the day so please respect your nieghbors, if not the whole world will become
like Hawaii (ALL BOOMING AND SYSTEMS ARE OUTLAWED!!!!THE POLICE TAKE THEM)besides you will go deaf if you keep listening to it loud all the time.
Don't go deaf!!!:
loud db is bad for your ears!:When your ears are mad at you, they will "ring" (doctors call it tinnitis). Sometimes they will "ring" instantly, from gunfire or sometimes you will hear ringing the same night when your trying to go to sleep or even sometimes the next day. If your ears ring "you had it to loud", turn it down next time until you don't get the ringing anymore. If you keep abusing your ears the "ringing" won't kill you, but it can, and will get LOUDER until it will keep you awake at night(no way that is cool). Furthermore, if the ear abuse continues your ears will NEVER stop ringing and that fun part is you get to live your life with poor quality sleep FOREVER...
Hearing aids are NOT sexy or attractive or cheap. Only you can decide if you want to trade in your 2000 watt sound amplifiers for hearing aids(just another 0.001 watt amplifier).
Loudspeakers:We can obviously provide hundreds of pages of data on speakers, but we will try to keep it very short. Cars make bass(low) frequencies louder automatically so for decent to good sound, one 10" or 12" woofer with 100 to 300 watts is plenty for normal people, and or low budgets. Lower than 120 db most people do NOT need name brand woofers or can hear the difference, however above 125 db it is a total night and day difference, get the good stuff. The mids and highs are more critical to good quality and or name brands and try to put the mids and high tweeters on, or in the dashboard, it will sound great reflecting off the front windshield. Look for quality signs like: bigger magnets, a cone that can pump in and out a large distance (X-max, Excursion, Amplitude), Higher power handling.
Surprisingly, low cost woofers can sometimes sound very good musically. the loudspeaker engineer knows that if he has a tiny magnet, he will have to use a tiny (light) speaker coil. Light coils are very responsive to frequency changes and higher bass frequencies like a bass drum at 100 hz. this makes a very clean sound, even though it may not be very loud.Also a low cost speaker design will usually be made "very tight", i.e. the voice coil gap is very tight and narrow and small,this typically increases sensitivity (db/watt) and musical cleanliness.
talk to us first before getting speakers but here are some speakers, will add more soon, serious woofers and reasons why:
Bass Boxes:This is better for non pros. if your a pro db only guy, you need a small and very high and peaky bass tune box. for the rest of us 99% , then, A bigger box pumps out:
3.bass that is deeper and lower in frequency
4.bass that shakes and vibrates your car harder(it "feels" better and more intence)
5.the box volume recommended by the manufacturer's is always at least 2 times to small. So you should AT LEAST double the manufacturers recommended box size. Make the box at least twice the size that they say. They recommend smaller boxes because it sells more speakers and because THEY already decided and THEY dont think you
need bass below 40 hertz!(talk about mood killers) All those technical
woofer parameters like Vas and Qts is a pathetic way to measure the force generation potential of a woofer, furthermore they totally
ignore the acoustic AIR FORCE LOAD.
6.A 10 inch woofer in a 2 cubic foot box will put out deeper bass than an 18 inch woofer in a 2 cubic foot box. This is because the 18 inch woofer is suffocating and choking in a box that is to small.
7. If you can do it invert your woofers. This means put them in the box "upside down" so the front of the cone fires into the box and the rear magnet sticks out of the box. This will make the inside of the box a little bigger, and then your woofer will be a little more relaxed and this means deeper bass and sometimes 1 to 4 decibels louder.
8.If your not interested in a killing people decibel level, and are more interested in awesome sound quality you can put the woofers in
different size boxes. So for example say you have 4 cubic feet in total and 2 woofers, instead of putting each in a 2 cubic foot box, make one side 1 cubic foot and the other in a 3 cubic foot box, this will make
the 1st woofer will better play the high pitched bass from
60 to 200 hertz, the other will better play the superdeep 20 to 50 hertz bass. This will happen automatically without any additional equalizers, crossovers or filters from your amplifiers. Your total db level will go down, but your sound quality will
go way up. Even better would be to port tune the
2nd larger box from 18 to 26 hertz for that
vibration bass. In general you can make 1 side
from 2 times bigger or 3 times bigger than the other. So for example say you have X cubic feet in total, then the small side is X divided by 4 = (X/4) cubic feet, then the rest of the box is for the other woofer.
making Bass Boxes:Dont make boxes if you and your buddys are drunk or tired. Someone could get hurt or you might make junk. Use eye protection at all times!!!!!!!Measure 3 times cut once! Use good quality wood at least 3/4 inch thick particle wood or plywood. If your using plexiglass or sheetrock or concrete or metal CALL US!!! have your HOME DEPOT or LOWES cut your wood for 50 cent a slice, it will save you hours of time. Remember they dont make perfect cuts, and they dont know that "Kerf" is the thickness of the blade usually 1/32 inch. not alot however if your box gets 3 sides together that are short that is 3/32 inch and you will have a air leak or weakness or the other side will be to short. So pre design and know your cut measurements, then when they measure they cut "ON CENTER" or "ON LINE" that way the KERF is 1/64 per side of slice. Bracing the inside of box is very very important. good to used 2x4 inch for internal bracing screw and glue. you can also use metal pipes but more money and time. you should brace a box bigger than 2 cubic feet.Even with inside bracing if you have really high db level use this range, 145 db or less is one layer or 3/4 inch wood panel, 155 db is 2 layers(1.5 inches), 160 db is 3 layers, 165 db is 4 layers, use wood self tapping sharp screws Number 6 FINE THREAD at 1 1/4 inch long. screw slightly at an angle for stronger bite. after or while your building on the inside use wood glue if forever solid install, use white or clear silicone if you might change something later. you can use the house fixing silicone. decide before you build your box if you want sound quality, super deep bass or high db, these are different boxes. take your time to build a box, you dont have to make it in 1 day or 2 hours. you can cut wood 1 day then another glue and screw, another day paint and polish or install in car. less stress is more fun.
Ported or Sealed Box Resonance Frequency:A vented box resonance frequency is most easily expressed as this simple math equation:
FREQUENCY RESONANCE = 51.71 x Square Root[(area port in square inches) / (Volume of box in cubic feet X port length in inches)]
PORT LENGTH in inches = 2673.9 X (area port in square inches) / (Volume of box in cubic feet X Frequency X Frequency)]
(AREA PORT in square inches) = (Volume of box in cubic feet X Frequency X Frequency)] X (port length in inches) / 2673.9
or in metric system units;
FREQUENCY RESONANCE = 54.59 x Square Root[(area port in square meters) / (Volume of box in cubic meters X port length in meters)]
You can also use mathematics to re-arrange this to solve for the box size or port length or area, if you already know the frequency of resonance that you want, or just email if your not to cool with math.
This is for the BOX only, when you put a WOOFER in the box it becomes a SYSTEM (box + woofer), and it may change the resonant frequency a little or alot depending on the strength and resonance of the woofer alone. Also remember at the resonance frequency, the woofer excursion per unit watt sound output is the lowest, so that the cone does not move very much but massive sound output is coming from the vent and it is also at the maximum electric ohm load.
Below the system resonance the woofer will act like it is in naked free air, and move violently and may be damaged.
Above about 3 times the resonance frequency the system will kind of behave like it is in a sealed box of the same size. In general, the larger the box and the larger the port the more sound output irrespective of the frequency.
SEALED BOX RESONANCE are roughly , 3.5 cubic feet for a single 10 inch woofer, 5 cubic feet for a single 12 inch woofer, and 8 cubic feet for a single 15, and 12 cubic feet for a single 18 for flat responce to about 20 hz. . when woofer excursion is about 1 inch or 2 inches back and forth, with very high power of 1,000 to 10,000 watts each woofer. For 10 hz flat double these box sizes. This is for the box by itself. The math proving this is very ugly. Also this is NOT for db contests, this is for better sound quality. this is because a larger box like this will lower your 40 to 80 hz bass where the db contests are, but will increase your superdeep bass below 40 hz db level, so your superdeep is louder.
A quick and 99 percent of the time correct way to find out resonance frequency is to get a flat frequency sweep audio C.D.(like ours) and then attach a multimeter to read AMPERES to any loudspeaker, inside or outside of a bass box(whatever). It should go:
Shut off any equalizers, epicenters, bass boosters, or any gains in your radio deck and amplifier boost switches.
1.sound amplifier black (-OUT) to loudspeaker black(-in).
2.Then sound amplifier red (+OUT) to AMPERE A.C. multimeter red (+IN) to AMPERE A.C. multimeter black (-IN) to loudspeaker red (+IN).
3.Play the frequency sweep starting from a low pitch(say 15 or 20 hertz) to higher pitch(100 hertz) slowly at a starting volume that makes the AMPERE meter read, say around 1.00 AMPERES alternating current at the start.
4. do NOT adjust the volume once you start the sweep.
The AMPERES will begin to drop automatically and go lower, to 1.00, 0.99, 0.98, 0.97 ect. until 0.33, 0.32, 0.32 it hits a low say 0.32 amperes, then it will begin to slowly go up again, 0.32, 0.33, 0.34, 0.35....
The point when the AMPERE meter reads the lowest AMPERES is your loudspeakers and or system frequency of resonance.
Our frequency sweep audio C.D. works really good for this because our sweep speed is (1 hertz per second = 1 hz/second). So starting the sweep at 10 hz, then begin play, 23 seconds later the AMPERES is at it's lowest reading, so this means your resonance is at 10 hz + 23 seconds = 33 hertz. This represents a "true resonance". As an example a 15 inch subwoofer with a resonant frequency of 25 hertz in a 6 cubic foot ported box tuned to 18 hertz, may measure 34 hertz "true". Sitting on a car with a "true" resonance of less than 31 hertz is quite fierce above 125 db.
The resonant frequency is not always your frequency db maximum.
This is because loudspeaker + box + amplifier + car = system. A system has a frequency at which the decibel level db is maximum, this is called the (Fdb). Use a frequency sweep disk to find out your Fdb, at about 10db lower than your maximum db, so you dont blow stuff up first.
In theory it would be nice to have a Fdb = (F resonance = Fres), or even better to have Fdb = F resonance = amplifier resonance(max power)= car resonance = loudspeaker box resonance = loudspeaker resonance.
With lots of time, money and expirimentation, my company has done this on several occasions, the interesting outcome is that the efficientcy of the system becomes extremely high, in terms of db per watt, and can achieve 125db to 133 db per watt. The total db level is of course also extremely high. Why is this important? remember the last +1.0 db will probably cost you 2 times your total amplifier cost, the last +0.1 db will cost you probably 50% the cost of your amps. System efficiency will save you lots of money!! and time!`
Amplifiers:Amplifier's are called:
AMP-lifiers, not VOLT-afiers...
AMP-lifiers, not WATT-afiers...
AMP-lifiers, not POWER-fiers...
"AMP" is short for "AMPERES"!!!!!!
high quality AMPlifiers are able to dump lots of current flow(electrons)
(AMPERES)into a low OHM load, usually the lower the better, so an amp that is rated into 4 ohms is better than an 8 ohm amp, and a 2 ohm amp is better than a 4 ohm amp. Some of the best and most powerful amplifiers in the world can push 0.4 Ohms or lower! Take the advice of professional with expirience what to buy , or just buy ours(we have many modified amplifier that push into a true 10 HZ!!!!from 400 watts RMS to 1900 RMS at a good price, get the HURRICANE that only 20HZ and 10 HZ can give you). You may also be able to test an amplifier, take 2 multimeters, 1 will measure voltage accross the (+)and(-), the other meter becomes part of the wire to the amplifier(this 1 will measure the current in amperes). Say your voltage is 20 volts and your current is 10 amperes, then you multiply them. So in this example 20 times 10 is equal to 200 watts R.M.S.. In general most amplifiers will push 2 to 4 times the voltage number compared to the amperage number. So in a more realistic example 20 volts will generate about 5 amperes or 100 watts R.M.S. most companies will call this a 400 watt amplifier. This is because peak is 2 times the R.M.S., (200 watts) and 0.1 second power is 2 times this(400 watts). So 100 R.M.S. gets "overated" to 400 watts, it probably can push 400 watts for (0.1) second however it sounds horrible and is totally distorted and more importantly your amplifier will die(cook) in a few seconds.
Please give your amplifiers fat, fat, fat wires. the fattest you can afford. they dont have to be fancy or name brand just fat, like a garden hose!!! 1/0 or 00 gauge, or your amplifiers will be weak, or make wierd sounds.
whats up with all this fat wire for the amplifier? its about resistance, in ohms. here is a table of ohms, from low to higher;
0.000294, 3 feet of 000 gauge =3/0
0.000735, 3 feet of 4 gauge
0.00515 is 21 feet of 4 gauge
0.0157 a normal strong car battery, 800 CCA
0.063 a large 3000 watt amplifier with 200 amperes
your wire and amplifier are competing for battery juice(amperes), the ratio of the ohm loads is the ampereage ratio also. so 21 feet of 4 gauge appears to be good, however the ratio of 0.00515/0.063= 0.08174, this times 800 amperes from the battery = 65.4 ampere loss! so the amplifier wants 200 amperes but in reality is only getting 200- 65.4 = 134.6 amperes, a 3.45 db LOSS!!!!MORE than half the power is LOST!! Furthermore, VOLTAGE gains or losses are even more important. 14.4 volts instead of 12.6 volts is a gain of 31% = 2.3 db. Look to keep it simple use 3 wires of 4 gauge OR 1 wire 0 gauge for 1 big 2000 watt amp.
RATING POWER! Most of the time amplifiers are "OVERRATED" by companies to sell more, they give you the "flame rating" this is the peak power at the moment it bursts into flames! Technically, to get the flame rating the factory intentionally kills an amplifier by testing it with a special machine and then connecting the + and - speaker outputs directly to each other without a speaker in between(a direct short circuit).This causes the amp to max death output for maybe 0.001 to 0.01 seconds, and presto... this is the flame rating.Some companies "UNDERRATE" to let you know it easily pushes clean power,and to keep a high quality reputation. Some well known UNDERraters are: JL Audio, Kenwood, MMats, Alpine, and of course Rockford Fosgate with there 1/2 suitcase size amplifiers rated at 100 watts R.M.S., actually more like 10 times that. UNDERRATING amplifiers , that's not a good idea or fair either, why? cuz you will cook your woofers! and half the time when you cook your woofers it shorts the woofer coils to ZERO OHM, so your amp dies also! WOW , ya thanks for UNDERRATING your AMP, now i got dead woofers AND a dead amplifier!! the typical classic correct SIMPLE way is (VOLTS x VOLTS(amp output))/OHM(dc nominal woofer) and play some normal bass music or tones; so;
120 volts@6 ohm = USA house outlet = 2400 RMS watts@6 ohms!
70 volts@1ohm= 4900 watts, rare high power,
60 volts@1 ohm = 3600 watts
50 volts into 1 ohm= 2500 watts, 2 ohm= 1250 watts, 4 ohms= 675 watts, 8 ohms=337 watts,
40 volts = 1600 watts
30 volts@1 ohm= 900 watts,
20 volts@1 ohm= 400 watts
10 volts@1 ohm = 100 watts
notice how power usually goes up as ohms goes down.
Everybody gets there feelings butt hurt about woofers and amps and power ratings like you killed their dog. their logic= my amp sticker label says 5000 watts, my speaker label says 5000 watts, it plays fine all day and never blows up, its loud: THEREFORE i must have a 5000watt system, WRONG!, in reality probably about 600wrms amp and 600wrms woofer REAL!!!
however, in proper defence half companies tell the truth, even though to db guy their overating lieing.take an amp it puts out 60 volts, with easy voltmeter now put it into 1 ohm woofer. watt = volt x volt / ohm, so thats a rating of 3600 watts, a 3600 watt label goes on it.for simplicity and history i can accept that as a FAIR rating, easy just use voltmeter, however at resonance a woofer can be 10x ohms!!!so 60 volts prob. at resonance ohms(10)= REAL 600wrms. this is the "old school" volt meter only rating, NOT the REAL wrms. because A.C. electricity gets complicated phase lags and ohm load shift changes.
a db guy from expirience will say; thier lieing it puts out ONLY about 700 wrms REAL. the wrms REAL is volt rms x ampere rms. so here 700 wrms/11.66 amperes = 60 volts. on youtube they got clamping test with volts and amps meters together, which is real! and time consuming. there are machines also but they usually "underate" slightly which is even MORE ANNOYING. some city electric companys power rate at 0.5 60 hz= 120th second. 1/10 second. its called "haversine" power. half a sine wave cycle at 60 hz. not enough time to heat up. 3 second burp is about a quarter that power rating. WRMS or similar EIA means all day and night 4ever, it can release the heat its getting, i.e. self cooling. i really did this as a university project; as an example boil water pot on 1 oven flame burner at max. the amount of heat the water is getting is ONLY about 550 wrms REAL! so we know to our human hand that $TUff is HOT!!!!!so an amp with 550wrms REAL is a big amp with alot of power. its woofer efficiency so low it doesnt seem that powerful. amps are efficient, woofers are not. You should use a real woofer also, direct resistors are not including the complex inductance , capacitance, phase lag, impedance.
To test measure the wattage power of your amplifier;
If its already connected and plays music good just skip to number 3.
1.sound amplifier black (-OUT) to loudspeaker black(-in).
2.Then sound amplifier red (+OUT) to loudspeaker red (+IN).
3.then touch the A.C. voltage multimeter red (+IN) to either loudspeaker RED (+IN) or amplifier RED (+OUT) and then
4. do NOT accidentally touch or connect an ordinary electric wire from amplifier red +OUT to amplifier black-OUT unless there is a loudspeaker there, or you will KILL your amplifier!
wattage is equal to volts times volts divided by speaker ohms, (Volts x Volts)/OHMS.
Also remember to use the fattest thickest wire with the shortest possible distance to the car battery, an amplifier factory rated at 2000 watts may only push 300 watts if you use junk wires that are to thin, then you will wrongly think "what a piece of junk AMP"(wrong!). What you have is a good amp with thin, skinny junk wire. Many amplifiers will not even turn on, if they dont have very fat thick wire(4 gauge or fatter) going into them, some will turn on but sound horrible. Serious car stereo people put in another car battery in their car near the amplifiers, for extra amperage. So the car will have 2 batteries. World class decibel car stereo people put in as many as 80 batteries, just for the amplifiers!
Different Amplifiers have different combinations of amperes and voltage for a specific power output. Say you have amplifier brand (X), it is 1600 watts RMS, you or somebody tests it at 80 volts at 20 amperes output. Now amplifier brand (Z) puts out 40 volts at 40 amperes for the same 1600 watts of power. Amplifier (z) is called a "high current" amplifier and is usually of higher quality, and 99 percent of the time cost lots of money. amplifier (z) is awesome for low bass frequencies and low ohm loudspeaker loads (like 1 ohm), and are usually monoblock subwoofer only amplifiers, but sometimes can be 2 channel. amplifier (z) will be very weak power in the mids and highs usually above 60 hertz, but terrifing high power output below 60 hertz! Oppositely amplifier (x) will play lots of power no matter what frequency your playing. and if it very strong like over 70 volts it probably will make your speaker hit harder because at resonance a speaker is about 4 to 8 times higher in ohms. so you wired your speakers to 1 ohm on a meter, when you play the resonant frequency you will probably be really at 8 ohms!!! and that 1 ohm monoblock is going to be weak! while the type x amp= type (ab) will be hitting hard and furious. these are also those old school amps that look like long surfboards.
Want higher db?, more power is usually a brutal solution. Most world champions have QUAD(4) coil speakers, and run a huge amplifier to each coil, we and our world champion clients run 2 amplifiers per coil, so 1 speaker will have 4 to 8 amplifiers powering it! 2 amplifiers per coil is called "stacking" or "strapped" or "strapable", only a few amplifiers can do this without blowing up and dieing(do NOT try it, unless the manufacturer of the amplifier says you can!). Some are called CLASS X or UNREGULATED CLASS D or HC or UHC (ULTRA HIGH CURRENT) or 1/2 OHM STABLE. If you cant afford to kill an AMP, DON'T DO IT. Only do it IF THE FACTORY SAYS YOU CAN. Ah... I can already hear the wallets crying.
Power is NOT the same!!!!
Watts are not the same!!!!
A watt of energy flow does not manifest itself in the same way. More importantly, it may not represent itself in a way that is meaningful to you and or your needs.
A bullet flying through the air has lots of watts of power, so does a laser beam and so does a 100 car train but none of this will help you the car stereo lover. Why?...
1st. of all most of the power is not manifesting in an electronic way.
2nd. even when watts are mostly electronic, they are a combination of voltage, amperage and ohm load and a complicated phase angle and unwanted heat.
Electronic watts are the multiplication of voltage times amperage, so (volts= amperage times ohms). So as a simple example you have a 1000 watt amplifier. Some amplifiers represent this as 100 volts with 10 amperes of current, others as 50 volts and 20 amperes.
The best choice would be the lower voltage and higher ampere mixture of power.
This is because amperage is the purest physical manifestation of force transformation from the magnetic electronic force, i.e. the M.M.F. (magneto motive force). I.E. the transference of the electron momentum to the physical momentum of a loudspeaker cone.
The scientific complicated proving truth mumbo jumbo is: mass times velocity = momentum = kg *v = p, then: momentum divided by mechanical resistance(z) = displacement in meters; (p/z) = meters; meters = displacement current = amperes; (kg EXP1,meters EXP1, seconds EXP-1)/(kg EXP1, meters EXP0,seconds EXP1) =(kg EXP0, meters EXP1, seconds EXP0).
What this means in more simple english is that a 747 jet airplane flying at 600 miles per hour through the air will COAST farther than a piece of dust lint in your bedroom, and a woofer with more AMPERES will generally push with harder momentum and therefore more pounds per square inch (P.S.I.) i.e. higher db; more DB, LOUDER!
Decibel or SQL Stereo Competitions:
World championship level cars are EXTREMELY MODIFIED!!!!!!! and most not even drivable!!! they gain 10 to 20db through car modifications over you even if your using the exact same stuff!!!!So dont get upset that your db number may seen low compared to their numbers. they also use microcars especially in europe!!!!
Trade, share or play music! (after your 3 second burp)(remember music? yes kids, in the old days we played our favorite song at db contests... unbelievable?!?!?! But TRUE. I know some of you youngsters out there are thinking "play music...thats wierd, man they were stupid back then..., scary...")
So many people forgot the "old school days" or are to young to know that
all this car stereo stuff was fun.
anyways...Car stereo sociology has been changing not for the better.car stereo 20 years ago was a whole family thing(stroller to grandma), music, SOUND QUALITY LEVEL, db all mixed together. then 10 years ago, all factory teams ,big money and mostly males , then 5 years ago- the basshead freaks, all db, all male. now its just become a pro,pro,pro specialist 4 inch bulletproof glass and steel db thing.normal people dont even get it anymore, and they sure dont go to a "just db" thing on a sunday. the events should to go back to family friendly.
0.Determine your time, money or sponsorship budget(sponsorship usually requires many, many years as a car stereo "pro"). A 130 to 140db system can sound great and impress lots of people and is not to expensive, 140 to 150db is going to take money, 150 to 160 is going to take big money + time. 160+db is going to take LOTS AND LOTS of money and time and dont forget to toss in the price of your car because you will have to make your car a "DEDICATED" S.p.l. car ONLY, which means no daily driving and a towing trailer. 170+db = CALL US and bring large and heavy amounts of $100 dollar bills!
1.Determine your most likely class or competition level, and size and number of woofers.
2.Get a sound meter and or spectrum analyzer, otherwise your just guessing.
3.Find someone in your area that has lots of expirience (years)
4.You don't want to drive a dragster to disneyland, so dont expect a db car to "sound good".A car that does a super fierce loud db, usually sounds horrible with music.This is because most db systems are tuned to a "spikey" higher bass resonant frequency(40hz to 85hz) instead of a lower frequency flatter smoother responce tuning(25hz to 40hz).
5.Realize that at about a "real 145db"(or about 152db in car competitions) the vehicle and windows are going to flex and vibrate tremendously, this is going to increase the difficulty in getting higher db levels. At this point you may decide to stay where your at or commit to bulletproof glass and fiberglass interior with no seats and a car that will NOT drive you or the kids to soccer practice anymore. It is possible to make a 145 to 152db system that sounds great, has basically flat frequency responce to 20hz, does pretty good db numbers, and is invisible to criminals looking in your car.
6.This is just elementary advise, We can answer extremely technical questions, just email.
7.sound meter test, re-tune, rebuild... sound meter test, re-tune, rebuild...
8.No one has a right to judge your level of commitment or dedication to db competitions,we are all different so when you not having fun you should retire or take a couple years break and come back again, or just go to shows and watch, or just find another hobby or "sport".
9.Even if its not your own car +145 db still "feels" great.
10.Bigger boxes = bigger db number
11.Many of the rules of db shows are arbitrary and make no sence, so chose your class and system well before your car gets put in bad or difficult choice because of some stupid rule.
12.Related to 11, make sure you have 1" extra, or make your boxes 1" smaller when you design and install them, otherwise:
1. It might not fit in your car.
2. at a competition somebody just might pull out a ruler and rule book and ruin your day. If your doing a big number believe me the rulers and rule books will come out.
13. We propose just a few simple rules in the unlimited class:
Rule 0. VOTING, yes VOTING just like for president, if over half of the voters think a new rule or even an old rule is "stupid and retarded" it can be voted out of the rule book. Only rule 1 and 2 will always remain and can not be voted out.
Rule 1.ANY competitor can rule book inspect or use any brand sound meter to test of any other competitors system at the time when the official judging or burping is occuring or about to occur.
Rule 2.At a competition you can not replace anything, dead decks, dead amps or dead loudspeakers(the equipment must be able to take the decibel abuse at least twice)
Rule 3.It must hit the same decibel number at least 2 times, lowest dB number "counts"
Rule 4.The equipment must be able to be purchased by anyone in a store(no prototype stuff)
Rule 5.ALL equipment in the system must be ELECTROMAGNETIC (no bs tricks or explosives ect.)
Rule 6.System must run on batteries
Rule 7.All speakers must be behind the 2 front seats, or where the front seats would be.
14. When in doubt, sprinkle everything with magic powder. This usually helps. If it doesnt, call or email us. we got really good magic powder!
Everyone and everything wants nieghbors with more similarities to themselves.
This is a force of the universe and is quite powerful. As a real life example find a car stereo of 145 db or more and try to "hug" or hold the car with your arms into NOT vibrating, it is basically impossible. At some shows you will see 10 guys trying to squeeze the car into not vibrating to get a louder db. Sometimes they are even on the roof "car surfing" if you ever get to, try it, most people think it feels quite fun to get "levitated"
up to 1 inch. Vibration is a result of the universe forcing the "smoothing out" of power flow inequalities.
Ohms:Electric resistance is measured in units called an OHM. An OHM is "like" a wieght like pounds. Standing at the bottom of a big hill do you think it is easier to push a baby stroller up the hill or a 18 wheeler semi-truck? Obviously, the baby stroller is easier, its lighter(less mass = inertial RESISTANCE). Now take 2 baby stroller's that are the same, except one will be pushed on ice and the other will be pushed on a floor covered with glue, which one do you think is easier? Pushing on ice will be easier because is has less RESISTANCE. Well OHMS is ELECTRICAL resistance. So lower OHMS is usually easier for your amplifiers to push. There are many limits to how low you can go though. Usually amplifiers can only go as low as 4, 2, or even 1 ohm if you try to go lower they overheat and burn up.
I know it may be a wierd thought but, human beings act exactly the same way as electric amplifiers! I will show you in this example: take a strong body builder who can bench press 300 pounds 1 time. He can also obviously bench press 2 pounds(less resistance). However, now lets add up how much total wieght he pushes in 10 seconds time, using this information about his bench press performance:
300 pounds x 1 time = 300 POWER units
270 pounds x 2 times = 540 power units
250 pounds x 3 times = 750
240 pounds x 4 times = 960
230 pounds x 5 times = 1150
210 pounds x 6 times = 1260
190 pounds x 7 times = 1330
175 pounds x 10 times = 1750 MAX. POWER OCCURS HERE!!!!
100 pounds x 15 times = 1500
70 pounds x 20 times = 1400
50 pounds x 25 times = 1250
25 pounds x 30 times = 750
15 pounds x 40 times = 600
10 pounds x 50 times = 500
(as fast as his arms can move, 5 reps every second also notice that here the amp and the human will start to overheat or injure themselves, by the way this is similar to pushing the baby stroller on ice or an conventional amp pushing into 0.5 Ohms)
Although not technically exact, but do you see the analogy? Pounds are the OHMS, so in this example we have from 300 pounds(OHMS) to 10 pounds(ohms), but notice that the maximum POWER does NOT occur at the lowest ohm load and it does NOT occur at the highest ohm load (300 pounds).
maximum power occurs somewhere in the middle of ohm load(wieght) and "repetition speed"(amplifier pushing voltage and amperage).
Further proof and an ironic twist that max. power does NOT occur at the lowest OHMS is that:
POWER = (AMPERES X AMPERES) x OHM
So if you have zero or close to zero OHMS you will have ZERO or close to ZERO POWER FLOW! (your muscles wont get bigger pushing a baby stroller on ice).
If your OHMS are zero your POWER FLOW is zero.
Don't worship power as "the one and only everything". Power is just 1 side of the story, a complicated story.
Another side is "momentum" as we will explain.
Another analogy for the voltage and ampereage coming out of an amplifier goes like this;
HUGE POWER but little, almost ZERO MOMENTUM.
Do you know your ohm load? Do you know your amplifiers ohms? Do you know your loudspeakers ohms? Make sure your amplifier is "happy" or it will NOT produce its maximum power(MOMENTUM TRANSFER).You must remember our goal is to transfer or exchange the maximum amount of MOMENTUM not POWER!!!!!!!
click to enlarge photo of loudspeaker ohms
Efficiency is classically defined as (power out / power in),
Efficiency = (sound power out / electric power in) = ((db(pressure) X db X area) / (volts X amperes))
and in the case of loudspeakers it is defined as the sound power output divided by the electrical power input. Loudspeakers are actually very inefficient transducers. Only about 1% of the electrical energy put into a typical home loudspeaker is converted to the acoustic energy we know as sound - the remainder being converted to mostly to heat and other type losses. The are several reasons for low efficiency.
1. The size RATIO of the diameter of loudspeaker cone divided by the wavelength of sound is LOW.
Even 18 inch cones are small compared to the wavelength of bass sound(30 hertz = 37 feet long). There is a difficulty in achieving proper impedance matching between the acoustic impedance of the drive unit(loudspeaker, low impedance) and that of the air(high impedance). This is especially difficult at lower frequencies. The better the acoustic load matching, the higher the efficiency. A simple analogy would be to pull a skateboard with an 18 wheel
semi truck, you can pull a skateboard with an 18 wheeler
but it is not very efficient(i.e poor gas mileage). Large horn loudspeakers that are used in movie theater cinemas, stadiums, or nightclubs are very efficient by today's hi-fi speaker standards.
Measuring the sound power output is not easy, but the sound pressure is relatively simple to measure. The sound pressure level (SPL) that a loudspeaker produces is measured in decibels (dBSPL). Ratings based on the sound pressure level are known as sensitivity ratings. The sensitivity is often defined as (db/Watt/meter) or (db/w/m) = decibels output for an input of one nominal watt measured at one meter from the loudspeaker and on-axis or directly in front of it, given that the loudspeaker is radiating into an infinitely large space and mounted on an infinite baffle. Sensitivity then does not correlate precisely with efficiency as it also depends on the directivity of the source and the acoustic environment in front of the speaker. As an example, a simple cheerleader's horn makes more sound output in the direction it is pointed than the cheerleader could by her own mouth without the horn, but the horn did not technically improve or increase the cheerleader's real efficiency. However, her total sound power output is increased.
* most car loudspeakers have a sensitivity of 83 to 92 (dB/W/m) - a low efficiency
* Normal house loudspeakers have a sensitivity of 85 to 95 (dB/W/m) - an efficiency of about 0.5 - 4%.
* Nightclub speakers have a sensitivity of 95 to 102 dB/W/m - an efficiency of about 4 - 10%.
* Rock concert, stadium speakers have a sensitivity of 103 to 110 dB/W/m - an efficiency of about 10 - 20%. In a stacked large wall array of 4 or more it can sometimes double this to 40% (a wall, 6 feet by 6 feet).
Our current state-of-the-art loudspeakers can approach limited efficiencies of 70% or higher under very special circumstances, and up to 99% efficiency at resonance. This is partly due to a very high magnetic field and partly to a high amplitude displacement (speaker cone movement in and out). The ratio of the sound output to the mass of the cone/coil combination grows significantly at high sound pressure levels i.e. above 140 decibels. In closed or small environments (bedrooms and especially cars) it is far more important to have a speaker with a high Xmax (cone eXcursion maximum) as opposed to high (dB/(Watt/meter)) rating. A higher Xmax indicates a taller wound voice coil and that the driver can move a larger volume of air as power increases. A few top of the line woofers have a very low "sensitivity" rating i.e. 80 to 86 dB/(W/m) (a nominal efficiency of 0.1%) due mainly to the very tall voicecoil winding. However at full power in an enclosed automobile may achieve 165+ decibels at 20% to 40% apparent efficiency. In general a low frequency speaker designed for high SPL's will have a larger and or heavier magnet, and a higher Xmax, and extremely high power handling in the 3 to 10,000 WATT range. Furthermore, in general the efficiency of a speaker increases the higher the sound db level and electric input level, as an example the same speaker may be 1% efficient at 0.01 WATT electric input, but rises to 25% efficiency at 3000 WATTS input with a very high excursion, provided it can withstand 3000 WATTS input and excursion without blowing up.
It should be noted that a higher power handling driver will not necessarily be louder than a lower power one. In the examples which follow, it is implicit that the drivers being compared have the same impedance. For the first example, a speaker that is 3 dB more sensitive than another will produce double the sound pressure (or play 3 dB louder) for the same power as the other. Thus a 100W speaker (call it A) rated at 100 dB/(W.m) sensitivity will be twice as loud as a 200W speaker (call it B) rated at 97 dB/(W.m) when both are driven with the same 100W of input power. For this particular example, when driven at 100W, speaker A will produce the same SPL or loudness that speaker B would produce with 200W input. Thus a 3 dB increase in sensitivity of the speaker means that it will need half the power to achieve a given SPL, and this translates into a smaller power amplifier and some cost and weight savings. This is very important in stadium concert touring applications.
For car stereo systems the apparent efficiency rises very high. usually a 10 to 15db gain over the 1 meter sensitivity rating on the product box label. This is because in a car the sound has nowhere to go and the internal volume of a car is much smaller than your bedroom or a stadium. A normal 12 inch car woofer in a car is about 100db/watt.
2.83volts into 8 ohms = 2 volts into 4 ohms = 1.41 volts into 2 ohms, or 1 volt into 1 ohm. an 18 inch woofer about 110 db /watt.
to really compete in car stereo you need at least 110 to 114 db /watt. a minivan with 16 twelves, 16 x 12 inch
will be about 120 to 124db/watt. systems that are higher than 124db/ watt are hard to build and are extremely loud
and compete seriously on the world championship tour.some of our violent rides have been from 124 to 129db watt.
these are mic readings at the front right windshield
window.Remember when measuring db and power input, that total power input is used so say you got a 15 inch quad coil 4 coil woofer each coil is 2 ohms. 1.41 volts per coil is 1 watt per coil, so the total woofer is getting 4 watts!!!!so you have to subtract the 6.02db gain 4 watts is over 1 watt. for the correct db per 1 watt readings.
this is even more complicated when you got 10 woofers, each woofer need to get only 0.10 of a watt so that all 10 combined equals 1 watt.In other words TOTAL power input per watt per db level. This is a very important number because on bigger systems somewhere about 1/3 to 1/2 amplifier power, you will probably get NON LINEARITY, in other words not very much louder. what this means in money is 2 or 3 times all your amplifier money to get the
last 1.0 db gain!!!!! so you spent 10X $200 per amp is $2000. now you will need another $2000 to $6000
to get just 1.0 db louder!!!!! in other words get your design right from the beginning because it is MUCH MUCH cheaper!!!GET THE DESIGN RIGHT IN THE BEGINNING!!!
Cone Speed:The Cone is the part of the loudspeaker that vibrates around when it plays music, especially bass music. Technically it is called the diaphragm. Cone speed is LIFE. Cone speed is everything. The goals of more db and or cleaner less distortion music is most effected by a higher cone speed. A higher cone speed also means a higher acceleration (cleaner music), and higher displacement excursion (more amplitude = more db = more cone pumping). As an example: a cone playing 20 hz moving at +-38mm= 74mm peak to peak(+-1.5inches or 3 inches peak to peak) amplitude excursion will be 160.0 db at cone face at 4.91 meters per second (10.98 miles per hour)WICKED LOUD. Put it inside a box or car and the db level may go even higher.(the db PRESSURE may go higher, but NOT the cone speed) ,in fact the cone speed may even go slower, weird huh?
Cone speed = db, once again very clearly... c o n e s p e e d = db, technically it is the cone face db(the most important db measurement).
To measure cone speed(cone face db) you must put the woofer in a SUPERLARGE box, then put a 1 to 3 foot long tube around and up against the front side of the woofer, so the sound fires into the tube of the same size as the woofer, then put the microphone into the tube, this is approximately the TRUE cone face db level.This is the proper way to measure the energy level coming out from a woofer, because it is the only time that db, acoustic watts and cone speed are all correctly mathematically related. Just putting a microphone up against the woofer cone without the tube in front is NOT accurate, because the sound instantly flys around to the back of speaker box and everywhere else.
Cone area is also second place to cone speed, unless you got 12 (fifteen's = 15 inch) woofers in your car! In other words it is better to have a smaller woofer moving like crazy, than to have a larger speaker playing like it is bored. The limit is near the speaker death. most world champions are CONSTANTLY killing woofers every few seconds, for the sake of your wallet and common sense we don't recommend it for the every day person or system.
We would like the car stereo competition db rules to change
so that any system must repeat the same db level TWICE (without replacing dead loudspeakers or amplifiers), then
db competition would be more about good design than largest wallet... nothing wrong with big wallets though.
There is usually some form of relationship with money and different forms of power from high car db type power to a 10,000 horsepower megayacht.
By the way, every db level should also have the conditions of the measurement stated. Simply put all db car stereo people ASSUME the meter is on the right side front windshield and or front center windshield, for those outrageously high 160 to 180 db readings! Great, so as an example; one 12" woofer high performance with two 6000 WATT amplifiers, i.e. 12000 ELECTRIC WATTS, the cone surface db = 158 db, the inside the small box level = 172 db, the in a MICROeuropean car front right windshield = 163 db, in a US small car = 155 db, box outdoors sound meter 39 inches away = 124 db, Or 12000 watts times 3 percent efficiency = 360 ACOUSTIC WATTS. what is our point? well this woofer brand X has ACCURATE, CORRECT db readings from 124 db to 172 db DEPENDING ON CONDITIONS!!! If someone says this speaker puts out 360 ACOUSTIC WATTS, or 124 db at one meter distance most car db people say "what a piece of junk" because they don't understand the meaning of acoustic watts, but if they say one 12" in a car 163 db at 12000 WATTS they go WOW that is great loudspeaker!, same woofer same meter!!!!Most true engineer's usually measure cone face db and or 1 meter away outdoor db level,NOT some Ultra Freaky Deaky(U.F.D.) world championship type micro car with 3 tons of concrete walls and 4 inches of bullet proof glass inside the car right front windshield db reading!!
And more than 1 speaker, like 2, 4, 8, 20 speakers and the db levels get to those freaky 170+db front dash windshield levels, so that now the 1 speaker at 124db at one meter distance is now 170+db, but yet the woofer has the about the same CONE SPEED, in other words the CONE SPEED db level is THE SAME!!! ,
nothing magical has happened to the woofer, just more cone AREA(more woofers)+(more db).
db compression V.S. db acoustic watts:
When you pump air into a bicycle tire or your car tire, this is air that has been COMPRESSED. So it has a db compression force, usually for your car tire it is PSI(pounds per square inch). 1 PSI = 170.75 db so usually we say P.S.I. but not db. Now take the air hose and blow a puff of air in your face. which do you think is higher db? the inside tire pressure or the puff of air in your face? OR are they at the same pressure(db)? Remember they both have the same input force and watts from the same air hose.
The answer is the inside the tire pressure is higher, it will also read higher on a db meter. Since both pressures are from the same air hose why should one be a higher pressure than the other?
The easiest way to explain it is to have a story analogy. Say your playing football and some guy tackles you down on the grass field, later on he tackles you sideways into a brick wall on the sidelines (not fun). the same input FORCE and same input WATT POWER.
what hit harder(more db)?
the brick wall tackle is much, much more violent (higher db) . the brick wall is a more violent interaction because there is no place for you go, you are sandwiched in between the tackler and the brick wall and you have to take all the force and watt power! Well that is just like the air inside a car tire is more higher db than the puff of air db level. The air atoms inside a car tire have no place to go, so they just keep hitting each other harder(more db) the more WATT POWER you add. The puff of air db level is lower because the air atoms get to run away from the air hose, the more WATT POWER you add the faster they run away from the air hose but you will not get any more louder db pressure, in fact your db meter may even read lower db! The air atoms are just running away from the air hose so fast they dont have time to hit the sound meter mic. and make it read a higher db.
All sound sources in the world make 5 things: air speed flow, air force, air pressure(db), watts, energy. All sound sources!, bombs, loudspeakers, car tires, mosquito's. As a car db competitor the goal is more air pressure, db (db pressure). Say 2 sound sources have the exact same input output WATT POWER and ENERGY, they can still have different air speed flow, air force, and air pressure db.
Depending on your car system with the same sound WATTS you can have very high db(pressure) and low air speed or very low db(pressure) and very high
air speed or any combination in between. it can get very complicated. Typically you can tell something freaky is going on when you double or triple your electric amplifiers watts in and your db (pressure sound meter) is the same or +- 1.0 db
different. The big test is close all your car doors and windows tight, read your db sound meter, then slowly start
rolling down 1 window, if you db goes down you have a db compression system, if your db goes up when you roll down a window you have a db sound watts system. If your sound pressure db goes DOWN with MORE electric amplifier watt power input you have a compression system with relatively weak coil woofers or woofers with short
coils that do not have much excursion in and out. OR chances are your car is starting to vibrate to death at 147 to 154 db. This means you need to add steel bracing for your car frame or bulletproof windows.
All High Pressure Sounds "feel" Different:
If you have expireinced decibel levels above 140 decibels, you know you can feel it.
In general the lower the frequency the higher the vibration amplitude level.
In general the human perception of vibration is inversely proportional to the frequency and proportional to amplitude, i.e.
(half the frequency = a -6 db change or likewise: double the frequency = a +6 db change).
So for example; 140db at 40 hz feels as "intense" as 134db at 20 hz or 146db at 80 hz, however most people will
say that 146db at 80 hz feels much more uncomfortable or annoying than 134db at 20 hz, even though 134db at 20hz vibrates and pounds your body and car much harder.
Some car stereos have many woofers in sealed enclosures while others have the woofers in vented enclosures, from personal expirience I can say that a car interior at 150db from air
tight sealed woofer enclosures "feels" much more violent than the same db level from a vented
woofer box. This effect is extremely noticeable if the windows are rolled down a little bit, or
a door is open. A majority of this effect is that in a sealed box system the acoustic power
from the woofer cones in attempting to leave the cone and radiate outward, anything in its way
including a human body will unsuccessfully attempt to resist this acoustic power flow. Also
the woofers are literally ejecting a certain volume of air(X-max excursion amplitude times total cone area), if the windows are up this air ejection resists as pressure(sound pressure level= total cone FORCE), if the windows are down or the doors
are open the air ejection resists as acoustic power flow(acoustic wattage= total cone area times the cone VELOCITY).
If you get the opportunity to go to a large "rave" party or front row at a large rock concert they sometimes will have a large 10 X 30 foot wall of very large refrigerator size bass bin speaker cabinets. Usually they play around 145 to 152db at 30 hz to 100 hz, but since it is 99 percent acoustic radiating outward power flow, it pounds and slightly moves your entire body. Sometimes they will not have a fence or security guard so you can actually lean up against the bass speaker wall, and the sound pressure db goes WAY up, especially if your body is "trying to block" the woofer sound wave. It is quite violent (like a football tackle) even with earplugs. This is just like a car system with its doors open.
One of the most powerful stadium rock concert systems I have ever worked on generated 118 to 120 db at an outdoor distance of 50 yards from the loudspeakers! ("THE WHO" rock musical group). At the last top row of the stadium 10 stories above and about 150 yards away the db level was about 110, and there was a 1 to 2 second lag time between the music sound beats and the immense vibration traveling thoughout the entire concrete stadium floor beneath my feet. Even though, by car stereo standards the decibel level was relatively low you could still sense the awesome thundering power coming from the stage framed by a 10 story tall 60 yard wide loudspeaker array. Even with such large distances and so much sound power coming from the loudspeakers, you could not really tell which direction the low frequency sound was coming from. The low frequency energy just completely engulfed and surrounded you, from every possible direction. Really words can not successfully describe it.
At another concert I was working at front row at a large rock concert
I was in front of the 4 front main line loudspeakers, each a large 3 X 10 feet very large refrigerator size bass bin speaker cabinets, oh ya FULL FREQUENCY RANGE(loud!). It was about 150 to 155 db! Later a "smart bomb"(concussion granade) was dropped at my feet, which blew me in the air 2 feet and backwards about 8 feet, db level est. 182 db. It turned the music at 155db into total silence!!! Later another "smart bomb" was dropped and it was about 155 db at 32 meters distance! WOW!
The light flash was also temporarily blinding. Even with earplugs a truly terrifieing expirience! I never wish to expirience again. It was a good idea I already had earplugs in.
Get a Bass Computer Generator:
Get an Epicenter Bass Generator, they are amazing and make music sound much better. They make massive subharmonic bass, but the added benifit is that it makes the high frequency sound more clearer and crisper. Later you can upgrade to one of our Epicenter frequency chips for 2 octaves deeper, truly disturbing low, low bass! that superdeep bass. whats superdeep? below 25hz, why?HAIR TRICK, the HURRICANE of air flow! if you got a system that has flat responce to 10 hz your getting basically 2 more octaves of music. it sounds way better and hits and vibrates you and your car much much harder.
human hearing is working to 20hz then -6db additional at 10 hz. actually all live recordings at all the studios in the world cut off at 40 hz (-12db /octave). per international agreement and RIAA. since in the old days nothing could really play that low anyway. so -12db at 20 hz is dog crap!!and -24db at 10hz is very "unnatural".there is NOTHING NORMAL OR NATURAL in big label music recordings, they kill the bass as they are recording "live".playing a drum set the bass drum the fundamental may be 45 hz but it drops at 6 db octave naturally -6db at 22hz, -12db at 11hz. is "flat". so down 6db at 22hz is minimum for "accurate" live drum reproduction.and this is only the fundamental. the 1st subharmonic is at 22hz flat anyway.
because everything can play down to 30 hz pretty easily. trying to get the bass below 25 hz is not easy. first you need a deck like a pioneer that has no subsonic 20hz cutoff filters. alpine have 20 hz filters so you wont get superdeep out of them.Sony decks like many others are flat freq when using the line outs, using the sub outs they cutoff bass, wierd huh.so use the real line outs. then you need an epicenter with our modified computer chip or bass processor with a bass chip or our modified soundstream BX12 that we sell so you can get the ultra bass frequencies. Next you need an amplifier that has a 5 hz or at least a 10 hz subsonic filter adjuster,this is after your epicenter or bass processor.Class d SONY XM-ZZR3301 has a 6hz cutoff, audiopipe amps have a variable cutoff down to zero hz.Jl has a variable to zero hz filter cutoff.most class AB amps has a switchable on/off subsonic filter so you will get flat responce. powerful amps that unfortunately cutoff bass we dont recommend; highfonics, SSI, Soundstream, Alpine. Make sure your RADIO DECK has a flat responce without a bass cutoff subsonic filter. if you want more you can get an pre amp equalizer that has a 20 hz or at least a 30 hz adjuster,this is after your deck but before the epicenter or bass processor that does not have a sub freq cutoff. then you need superspeakers with a very high xmax, like 18mm OR MORE and a superbig box tuned to 25hz or lower. because everything can play down to 30 hz pretty easily. trying to get the bass below 25 hz is not easy. first you need a deck like a pioneer that has no subsonic 20hz cutoff filters. alpine have 20 hz filters so you wont get superdeep out of them. next you need an pre amp equalizer that has a 20 hz or at least a 30 hz adjuster,this is after your deck but before the epicenter or bass processor. then you need an epicenter or bass processor. with a bass chip or a modified soundstream BX12 like we sell so you can get the ultra bass frequencies. you need superspeakers and a superamp, and probably a superbig box tuned to 18hz.
1. dont leave valuables visible to people walking by especially C.D.'s or IPods, put them in the trunk or at least hide them under the seat.
2.Get an alarm for your car
3.dont BOOM LOUDLY near your own house!(your telling criminals to come and visit you later, when your sleeping!)
4. Stop bragging and shut your mouth! So your system is 150+db, shove a cookie in your mouth and shut up(nobody cares... besides let the sound meter do the talking for you).
5. you should know if the type of people in the area your parking at are criminals, drug abusers, or just desperate(especially those crystal meth heads). Alarm or not they can and will break your window in 5 seconds for a $2 music C.D. left visable on the front seat, so they can trade it to get high, and cost you a couple of hundred dollars to fix the window-even if they dont want to take anything else!
DR PHIL and Team Kneepads:A "Dr. Phil" is someone who THINKS they know everything about all things.
They love to point fingers at everyone and tell them what's wrong with there life and car stereo.
More annoying, they do this even though you never asked for their help or advise.
"Team Kneepads" luv kneepads. either they put em on or give you a pair to put on. and usually they just wants your initial joining money fee or other fees or service payments, or want to sell you a specific brand of equipment with no discounts, they do not really know who you are or care. Usually at car shows Team Kneepads will dive to slam the car door in your face so you CANT see there cheating system or other "magical stuff". They usually hate NEWBEE'S and beginner's and questions. They usually hit big db numbers and do very well, BECAUSE they dont let you join UNLESS you hit a specific VERY HIGH db number for your class. Even after a show, they hate playing music on a car stereo system, so stick to playing the "1 note wonder burps". They will not talk and do not like to talk to you if they dont know you, BUT if your somebody they know or somebody that THEY respect or you hit 0.1 db higher than them, THEN OUT COME THE KNEEPADS!
Oh ya, both Dr. Phil + Team Kneepads never help in any REAL way,
So the next time some beeah comes up to you like Dr. Phil telling you; "you gotta do this and you gotta do that " tell Dr. Phil to suck Oprah's D***".
Seriously, all of us have enough problems without some clown telling us we should follow his sinking ship to drown. Find out for yourself, or ask someone you should really respect, like a priest or a car stereo world champion or international car stereo corporation, even then believe the sound meter, it rarely lies or tells you a Dr. Suess, Cinderella story.
Worse yet some are some internet clown forums, where so and so is a "senior member", "forum moderator", "Senior Judge" or has a tatoo of it on his a**. The funniest part is that he says your not: "rated", "certified", "a member of Team Kneepads" and talks S*** about your system.
Sometimes they will make fun of you or call you a NEWBEE or NUBE because you committed the crime of "trying to learn".
You tell that Dr. Phil to suck Oprah's D*** too.
better yet skip the BS forums and just go back to a college or pick up a book you don't really understand and keep reading it until you do. Or go to a real car show near your house and just talk to real people. So your on a limited budget, all of us are, wipe the tears and do the best you can!
See the picture of the car at the top of this page, they just don't come raining down from the sky for free.
There are good teams out there, I call them "Team Cool". They know who you are, your system, your last system, the future system your planning. They always get you discounts or sometimes free stuff if your a heavy hitter, they will sometimes all go to your house to help you with a new system, at least one of them has a sound meter, they do REAL STUFF with you in REAL LIFE or phone, not the internet chit chat that does not get anything done. Team Cool usually lets you in there car or see the system and talks with you. Team Cool loves beginners, and helping beginers, so Team Cool usually has a wide range of db members all parked together, from the 119 db beginner poor guy to the 170+db world champ. Team Cool also loves music, and usually there are many ipods and many styles of music from rock to classical to rap to rave. Team Kneepads think music is a 100% waste of time and valuable battery power and so they only BURP and BURP.
Good stuff comes from hard work.
Don't talk about it "be about it".
The real players, movers and shakers, world champions don't have time to talk about this and that and all the stuff they plan to do NEXT year. NO TIME on the internet or anywhere else for that matter. Nothing personal, it is just real success involves hard work, and hard TIME, NOT hard talk, and NOT internet drive by gang banging.
Besides with all that time your wasting on the internet talking S***, remember you could be listening to REAL LIFE BASS instead.
D Mighty 6x9?:I know your thinking wtf. Well a long time ago there were not many LOUD systems except at the movies or a rock concert, until one day along came a 6x9. Now it didnt shake your house or kill peaple, but they were very loud for the time(before ipod time). It was also the first speaker to accurately and cleanly play the 30 hertz note at a flat frequency volume level !!My first expirience was one day a friend came over with a pair of 6x9s that were made by a rock concert speaker company and they were the best you could buy at the time. He said he wasnt sure if how to install them properly, so I built a 1 cube foot box for each, one in the backseat and one on my lap. It was vibrating my body and it was putting out a really loud amount of music half on us half out the windows, and not distorted or anything, just clean and really loud! We drove by our nearest high school, and proceded to see the head whiplash our car stereo was making to the people walking by! It was great. Whiplash, Girls, phone numbers, loud.
The problem was that in the mid 1980's car stereo makers cut costs so instead of the 25 to 50 watts r.m.s they went down to a pitiful 2 watts r.m.s.. In fact even today most car stereo decks, even expensive ones are 2 watts r.m.s!!! So car stereo installers just started wireing up the 6X9 to the 2 watts instead of trying to sell the customer another 200 watt amplifier, guess what, 2 watts sucks and slowly 6X9 started getting a bad reputation for not being loud.
However, even today just find a pair of good quality 6X9s with 200 rms watts to each and put your face in it. play normal music or rock n roll, not the bass computer stuff, and tell me that is not loud! You will be lieing if you tell me that is not loud! A pair of 6x9s are really loud if there playing normal music not the death bass stuff. After discovering this, I proceded to install 4 of these 6x9s in all the low rider car rear decks i could find, man those were loud especially for the victims in the back seat! Even to this day for a high db 150db+system I always put in 1 or 2 pairs of 6x9s, at least. Figuring at the dealer price of about $10 USdollars each, they are really an amazing deal even today in 2010!! Oh ya, there are a few db car stereos in europe using around 20(twenty) 6x9s putting out between 150 and 169db!!!! WOW!! for 200 bucks!! Yes D mighty 6x9.
SOUND QUALITY:Almost everybody wants sound quality, even the BASS HEADS or db KINGS. Most of the time the db guys sacrifice sound quality for db. Most of the time it is quite obvious when a sound system sounds good, or which car or stereo sounds better than another. I have judged many db and sound quality shows, and it is really quite evident when a sound system sounds really good.
What is not so clear is when a system is "suppose" to sound good and it doesn't, and when a system is "good" yet doesn't sound good, and when some classical music lover claims your sound system is not "FLAT" on the equalization curve(they love to say car stereos are "bass heavy"). Then you have some millionaires spending outrageous amounts of money to get "accurate reproduction"(whatever that means). We know what that means and we will explain it later, because as we will show sound quality is very ,very subjective(changes alot on who you are or what sound sytem is being used or where you are). Then the RTA real time analyzer guys saying your system is "spikey" or "nodal".
First of all, what is sound quality? How do we define it? Who defines it? Who gets to define it? Why was it defined in that way? Many questions yet the answers are quite surprising, and raise even more questions.
Let us first be clear that most of the problem with sound reproduction/playback and recording/playback is microphone and loudspeaker related, very little distortion is caused or introduced by the "pure electronics"(amplifiers, mixers, computers, AD, DA converters, CD burners, wire, cables, ect.
High sensitivity and loudspeaker efficiency definately make a sound system sound better, along with higher power amplifiers. Why? higher sensitivity means higher cone acceleration, larger amplifier means faster and higher cone control braking, combine the 2 means a very controled and faithfull woofer cone.
Factors affecting sound quality that will eventually be explained with more time check back for more info;
Signal to noise. This is the db difference between the sound you want to hear (signal) and the sound you
don't want to hear (noise). The larger the signal to noise db number the better. Various signal to noise ratios
are listed below, in order;
Object VS noise
Object distance VS source VS loudspeakers VS ears
Total SPL (db) of the source is very important. The db levels of the recording playback should be close to the actual source. If you record a singers voice that is about 85 db in real life, you should listen to the recording at about 85db. If you record whispering at 40 db you should playback the recording at about 40 db.
Loudspeaker Goals. A loudspeaker has many different jobs and many different goals, usually these are
competing and conflicting goals. here is a short list of goals;
Microphone Goals- lower cost, flat frequency, high db levels
Recording Engineers and Soundmen. These recording engineer guy's are people usually with very good hearing and a love for music. The problems that can happen is that over time the high db level music they have heard all their life catches up to them and their hearing suffers. Also their ears are not your ears. The sound systems they listen on when making recordings is not the same as the sound system your using when you listen to their recording. We are not going to list all the good recording studios, but TIME WARNER, ABBY ROAD, and most ELECTRONIC RAVE MUSIC recordings because they are usually all digital, from source to recording to CD.
Many top 10 songs are sung totally flat and out of tune, i.e. some notes that shakira sing are way out of tune, but shes on the top 10. many people cant hear slight out of tune notes, say note A 440 hz from off tune A 443.2 HZ
My clothes are moving...this must be a good sound system? The first time i saw my clothes move was in from of an array of large bass bins and a concert. may pants were MOVING! I couldnt believe it. The bass was moving my pants! I had earplugs in, but could not resist climbing into 1 of the large bassbins and my pants were moving like a hurricane!! And the wind was cold. IT WAS SO EXCITING AND SICK! I realized this is what I was missing in my life, and that I need this. I needed this and i did know why but I knew I needed this in my life forever.
Record any cricket chirps lately?there are some Phd students or NATIONAL GEOGRAPHIC employees who occasionally record cricket sounds or tiger growls or equally bizarre sounds. They try to figure out the difference between a cricket thats sick or has a sore leg versus a healthy cricket ect. Anyway they contact me about getting flat frequency response and absolute fidelity. ok, great. maybe i can, sometimes maybe i cant. but for sure when i do, it sounds like crap when you play music though it. Why? millions of reasons. the main one is that "perfect" fidelity flat systems have no harmonic content(just like criket chirping) and no surprise music(huge harmonic content) sounds horrible on these type systems. this is basically the same reason a "stratavarious" violin cost $6 MILLION dollars and an ordinary violin costs less than a $500.
Linearity and non-linearity. Is given alot of importance by alot of people.I really dont think it is that important, either way. Usually in the normal 60 to 120db level of music listening linearity is constant and smooth and correct.car show judges usually will deduct points if your system sounds more ofr less bassy with changing volume levels. They want the ratio of the highs to the bass levels to sound the same no matter when the volume knob is.
Money. The cost of audio electronics has gone way way down. everything is so low price now. money usually doesnt stop you from getting the type of sound that you want.
Flat response?Most people think flat responce is 20 to 20000 hz.Incorrect. While this is the range of most human hearing, there is still 1 octave higher and lower which the ear and body percieve, it is also called the first harmonic or first subharmonic. So that would be 10 to 40000 hz. VERY few systems are flat responce output to 10 hz. the first reason is most amplifiers put sub filters that kill the bass. They usually say 15 or 20hz but really start filtering below 30 hz. This is annoying!look for amps with a on off switch that lett you decide. Our company also specializes in modifying bass computers or epicenters and certain car amplifiers to play to 10 hz flat responce at reasonable prices, 1500 watts RMS@1 ohm to 3000watts RMS @1 ohm clean.just email us: email@example.com
Cost and Price
Normal ears VS good ears VS the human limit
Source size VS reproduction size
Time smear. there several kinds of time smear. first is when your speakers are different distance from your ears. second is when the shape of the speaker causes the length to your ears to be different.3 and very important is the speaker cone acceleration. recreating a gunshot is hard for speakers, gunshots and fireworks are 25 microseconds fast. speakers are not that fast and our ears can hear that time smear.
Who knows how loud composer BACH or MOZART would have his bass level and car stereo?
Computers, MIDI, SYTHESIZERS, SMPTE ARE NEW INSTRUMENTS without definitions. it is US, OUR generation that is deciding how loud, and how much, and how synthetic music should be or is becoming. In the 1700's the composer BACH was revolutionary and ahead of his time and was ocasionally banned from playing certain songs, because they sounded to "abstract, heresy and ungodly".The same situation is going on now, with some people saying this and others saying that.
Snobbery and people who think their better than you. People who think or like to think that their rich are usually snobs. With real super rich people it is obvious, like britney spears or other famous people or corporate CEO's, or usually because they have many houses all over the world. These people usually try to "fly under the radar" and do not brag or "rub it in" the fact they have lots of money.Snobs, however love to "flex" and brag about their systems, and usually like their bank accounts, it is not as great as they claim it to be. These systems are usually nice, but not top of the line. You can get this stuff at the expensive part of your neighborhood circuit city or best buy. Nice? yes. "flexing material" no.
Louis Vuitton sound systems, are very exclusive brands that no one has heard of, or that require an invitation or reservation to hear and purchase in one of their exclusive showrooms.Looks very beautiful in usually mirror, chome, or iphone style mirror black digital faceplate. Handmade and usually in the US or some european country.Sound good? High Quality?you bet! but $46,000 for speakers and another $25,000 for the receiver to play them on, makes me rather buy a corvette car with the money.
Sure looks good to me
Do you want a cookie? This is about people or companies that over market and underdeliver. They brag about this and that but when you look at the numbers, there not what they claim or should be. So instead of listening to their stories just hand them a cookie instead, at least it might keep there mouths from bragging a little while.
Microscopic shock waves. Many ordinary sounds have Microscopic shock waves in them. Suprising huh?. No reason to be scared though because they are very small in size, however they are fast moving particle of air and reproducing them accuratly is very hard. Like the sound of an ordinary hand clap, or a bag of microwave popcorn popping, or the very hard rubber toy balloon pop. You can test the sound quality of a speaker using these sounds for a bery hard test.
Infrasound (bass)Are your clothes moving when you hear the system? if so chances are you got some bass power. even better ultralow power that you really cant hear like infrasound like an earthquake, you hear things around you vibrating louder than the sound itself.
Ultrasound (superhigh frequency)
CD's suck. why?Its because they "quantize". Quantizing means they turn analog into digital. this is great and fine in the low frequencies but above 5000 hz and more they begin to distort the original sound wave. gets worse at high frequencies, at 20,000 hertz it is 50 % distortion.
MP3's suck even more. like CD's they quantize, but worse they also high frequency filter, above 14,000 hz you hear nothing. after a few hours of mp3 listening many people get a headache. no high frequencies is the reason why.Furthermore, nightclub sound systems are usually about 110 to 120 db in the vocal frequencies, play to many mp3 at that volume and people will begin to complain about the crappy sound. normal people will complalin, not just stereo people that have better ears.
Headphones:real serious people about sound ONLY use headphones, nice, big expensive ones like sennhieser. stereo separation is basically infinity, frequency response is flat, frequancy resonse to 10 hz, zero time smear and crossover distortion is zero. seriously headphones are the ultimate sound below 120 db.by the way headphones are big outside the ear things, not baby tiny earbuds like on ipod or walkmans, earbuds suck.
Turntables: are the best for good quality analog sound, this is because there is no analog to digital distortion and no high frequency distortion like with CD's and mp3's. get a good needle, like a shure V15 or stanton 550, or ortofon.
Mosfet VS Tubes VS I.C. VS IC emulators/simulators
Stereo, 4,5,6,7,8 channel or N-channel systems
Can I get an echo?All real sounds have an echo. it may not be a loud echo but there is an echo. Unless your receiver or recording has the echo or an echo function in it you will never have the "authentic" sound.
Computer controlled systems
Planned obsolesence. Companies are usually trying to increase profits by makeing new models every year or 6 months like apple phones, why? greedy! Is the new model is better or different? yes, maybe. does it matter to you you? yes, no, maybe? future changes they are already planning- killing the CD. why? cuz they cant make money off you.changing to 40 volt car electronics. changing to a car that nags you, txt you, and emails you. killing off all bass below 20 hz, why? cuz their dumb. The iphone company today decided to make the i7 with the no headphone jack!why?? i know why, MONEY, CONTROL. the power to do that without asking your opinion gets them high.waterproofing a headphone jack is easy and cheap, they dont want that for you, they want to squeeze the money out of you, squeeeze you like a lemon making lemonade! in scary news i cant make up: DISNEYLAND is taking fingerprints today!just like an arrested criminal when they go to prison. we have to think and let these companies know we dont agree.
Can I get some fries with that shake? Some high power car stereo's can violently shake and vibrate a car and anyone in it. Most people are scared at first but them begin to love it. Vibration and thunder and lighting is a basic human primal instinct and fear, for thousands of years.This releases primal hormones in human beings and generates a new type of listening expireince. Now that we are fortunate to live in this time where we can recreate this whenever we want is truly a blessing. From a technological perspective it is a fact that a system that can do this is to some extent IS HIGH QUALITY (although not always perfect sounding). Equally absurd are some "audiofiles" who listen to low bass music through loudspeakers with 6 inch "woofers" claiming the "fidelity" is outstanding. Even if the fidelity is good the thought of weak 90 to 100 db bass has me yawning.
I have the right to hear what I want, in the way I want to. Some people want the bass at 140db and the highs at 90db. some people dont like bass??wtf??some people dont like bass so they listen and 80db. most people like the bass 20 db louder than the highs, this give a powerful cleans sound. most stadium systems are 0 to 10 db bass gain.
WE will add alot more on this later
Hyper technical:This is an amazing and profound article written by the late, great SUPERHERO of
"bass in your face", Elmer V. Carlson for those who are lucky enough to understand it;