anyone seen 4 15's 4 12's 4 10's and 4 8's in a bird?

 

there is a picture floating around here, of someone with 4 12's in a camaro, custom box though

 

i mean all of them 16 total at once

 

that would sound horrible, and wouldn't be worth a damn in an SPL contest. Totally pointless.

 

well how would you figure .... have you ever heard or seen it? i have my own car audio shop and ive had more people thats its not possible to fit them in but if you think about it if you have every range of frequencys then hit every range of bass equally . ... and weather of not what you think is pointless . ... could just win me 50 g's at IASCA ....... because ive already tesed it and hit 168 Db with a junk *** setup

 

if you owned your own audio shop, you'd know all about the multitude of phasing issues associated with the huge quantity of crossovers necessary to break the 2 or 3 octave range apart to feed that many different speakers.

If you owned your own shop, you'd also know that if you don't run them all at the same frequency that compliments the transfer function within your vehicle, then the only subs that have any contribution to the SPL are the ones that happen to be getting fed the frequency range that the transfer function is in.

If you owned your own shop, you'd know that if you did run the same signal to all of them in any sort of series-wired configuration, the sound quality would be horrid because every size sub is going to have a totally different frequency response, as well as a totally different impedance curve and driver characteristics which is going to result in back-fed EMF, which in turn is going to create a ton of distortion with that many non-identical drivers.

Sorry guy, but your overwhelming lack of a clue is really scaring me, and I hope for the sake of your customers that if you really do own a store, you let somebody else sweat the details.

Show me pictures of the car, and pictures of the car getting metered with 168dB showing on the RTA, and I'll shut up.

 

hahaha i love jim
:lala:

 

I hate to sound like a know-it-all, but if I'm going to disagree or especially argue with somebody, I'm going to support my side. 90% of the people that disagree or argue with me can't ever support their side of the arguement... which is of course because they are wrong. I only argue my side when I know I'm right, and if I know I'm right, I can support it with factual information, not opinions or "joe told me...".

Once in a while, I'm wrong, and if the person can provide me proof, I'll eat crow and admit that I'm wrong. I'm as willing to learn as anybody, but the vast, vast majority of the topics discussed here are topics that have already been debated/discussed at length, and are also topics that I have plenty of first hand experience with. Of course, understanding the electrical theory and the physics associated with this stuff doesn't hurt either.

 

Jim I noticed that you were talking about electrical theroy I was just wondering what you do for a living? I have been out of high school and am thinking about going to school for electronics. Where did you go to college? A friend lives in Rochester and recomends the technical school in Rochester (his boys both went there) I know this is off topic but I couldn't help myself. Thanks James

 

I'm an electrical engineer. I went to RIT for it.

 

Thanks Jim that is the one he was telling me to go through. Do you happen to know Jake Hendrix by any chance? His father said that if I want an electricl enginer degree that is a good place to go.

 

Never heard of him.

 

ONLY 168 dB (note the CORRECT abbrev.) ?????

Mama gates pushing way over 175+ dB now.

I might be a little nobody, but I did get invited to 1996 IASCA Nats by Mitek Corp (MTX to most folks!) and put up in their suite.
Little did I know it was a job interview!

At the time I had a 7 y/o son and would not relocate to AZ.

 

:sillylol: Jim OWNS

Sorry Guy, it will sound like ***. I *thought* it would sound good too, and had never tried it or done any research, so i mixed 10's and 12's in my trunk. Sounded okay, but on fast songs where the bassnotes were close, you could tell it was a ****ty setup. Wasnt even worth having more than the 2 12's. When i took out the 10's it got BETTER.

Its much more worthwhile to sit here and read then to try this **** out, trust me.... Besides, finding the cash to amplify 16 subs cant be easy....... But i bet you can just get them at cost at your shop...

 

funny thing is, why 16 drivers when guys are hitting over 160 with 2 drivers and a wall? 16 drivers not worth the time or the effort to make it sound good or hit like it should

 

never mix different sized subs together

 

It never ceases to amaze me that people can just think they can throw whatever they want into a car with out any knowledge of speakers or sound for that matter. There is so much science, factors, and formulas that you need to account for to achive a good sounding system. Why take 16 subs when you can achive the same dB (if thats what you're into) or SQ with a dual 10" setup. I'm going for a single Memphis SHP 10"or a single 10" Diamond D6, two CDT HD briaxls in kickpanles, and two Memphis amplifiers. Everone and their brother can go buy a trunk load of
Sunday special subs and throw them into a car, but to find a good sounding system with concert-like imaging, that sits in stock looking panels, and enjoys rides down the street to work as well as rides down the strip in 13 seconds is becoming rare. That is my goal. Go ahead and stuff 1,800 18" subs in your car, I just dont see the point in having that much SPL when your ears bleed when you turn it up. Even though my shop I work for has a van with 16 subs in it, I would rather feel like I'm in a concert than on a vibrating bed.

Just my opinion,
Matt

 

It's different strokes for different folks. I think purpose-built SPL machines are every bit as impressive as sound quality machines. It's just that mixing all of those different subs will accomplish neither.

You'd also be amazed at the physics that go into making an SPL machine. We've gone far beyond the realm of stuffing 20 subs into a minivan and getting records. To do well in SPL competition these days, you need to have serious talent, and a thorough understanding of physics and electrical theory. having a mechanical engineer on board is pretty common for some of these teams too. First you need to build a vehicle that can provide a very small, very rigid chamber that's capable of withstanding high pressures. A lot of the newer vehicles are doing this by having a chamber built within the vehicle. The windshield is usually super thick lexan or plexi, and the doors are modified to be airtight and are pulled closed with air powered actuators. The chamber is built with a specific transfer frequency in mind. The sub enclosures are also built to maximize output at this same frequency. The sub enclosures are usually smaller than what you would build for the same subs. This causes a peaky, narrow frequency response, which when paired with the vehicle's transfer function, provides a very efficient output within a narrow band. Likewise, the signal being sent to the amps is passed through a narrow bandpass filter so that no power is wasted by producing signals out of this narrow window. The amps are usually very high power amps (though not necessarily rated at such) that are highly modified compared to what is commercially available. I don't know specifically what modifications are performed, but my guess is that all nonamplification-critical functions are disabled to conserve power, and the amps are modified to withstand the ultra-low impedance loads they are presented with when pushing paralleled speaker combinations. These modifications are done mainly by routing large gauge power wire directly to the amplification stages instead of passing the power through the printed boards. The amps are also fortified by massive amounts of capacitance. The result of these changes is that you have amps that are capable of providing ridiculous bursts of power for a very short period of time. This is why all of the high power systems "burp" the system instead of playing for extended periods of time. They send a signal with a frequency centered at the system's most efficient point through the system for an extremely short period of time. The result is the ability to provide substantial amounts of power to the subs for a very short time. No dynamic compression to the subs from heat, and no heat damage to the amps. For that very short time frame, the subs reach maximum excursion and pressurize the air-tight cabin, resulting in an insanely high SPL.

Mid/low 170s is where the best vehicles are at now, and it's not going to get much higher. The funny thing about SPL, and air compression in general, is that as the pressure rises, the force required to raise it increases at an exponential rate. Theoretically, 200dB is the absolute maximum SPL capable at standard air pressure with modern technology. I can't specifically recall the physics behind that number off the top of my head, but it's well documented. For somebody to claim 168dB with a "junk *** setup" is just pure fantasy. It can't happen. I don't think that Team Yates has been able to break the 170dB barrier since converting their equipment to Kicker from the PPI stuff that they previously used, but this guy got 168 with "junk ***" equipment. Sure.

My fingers hurt now. I hope somebody learns something from my novel to make it worth it.

 

i for one appreciated your dissertation .. very informative, as usual.. thanks jim!

 

I like it that trans am racing didnt even try to defend himself once he knew that Jim had him as a fraud.

Brian

 

Don't let Jim lie to you. He doesn't have a job. Instead, he really just patrols these boards 24/7 to expose idiots and help people learn




Just messin with ya Jim.

 

SPL definatly requires a lot of knowledge if you plan to suceed in it. Like I said earlier my shop has a company van with 16 subs in it. Even though it has a lot of subs there was a lot of physics and theroy put into the design of the box down to its construction .Subs were aimed for minimal cancellation, airspace and voltage requirements were adequate, and of course the "Wow" factor with all subs arranged nicely.

Yeah, I hear a lot that someone can get 130 dB and they think a little tuning will give them 140's. Sound pressure level increases exponentialy, which means (in dB) to reach a level twice as loud as your curent level you would need to increase 6 dB. *I THINK* I'm not positive on the equation.

Later,
Matt

 

3 db increase will double the sound.. but yah, you have the right idea.. its humerous to listen to people who can "tweak" their system from 130 to 142.. mmhmm.. i can tweak my volume 4x louder than it is right now too.....

 

Just to clarify, double the power gives you a 3dB gain. An actual doubling of volume requires 10x the power.

 

hmm

 

It's like this. the Bel scale is nothing but a ratio of two volumes. The reference volume we use for giving arbitrary volume levels is in relation to the threshold of human hearing.

Anyway, to compare the dB of two signals, it's like this:
dB=10xLOG(A/B) where A and B are power levels. Say that A is 200 watts, B is 100 watts. That gives 10xLOG(200/100) = 10x(.3)= 3. In other words, The output in dB from a 200 watt signal is 3dB higher than a 100 watt signal.

 

this isn't a bad explanation:
http://www.anandtech.com/showdoc.html?i=1317&p=2

 

thank you once again jim, that article (and your explanation) cleared things up quite a bit!

 

Its good to see some physics being used to explain things. to Jim.

Hey, do you happen to browse car sound, or any of the other car audio forums?

 

I used to hang out on the carsound forum, but there's even more know it all 16 year old pimpleheads there than here. At first it was worth wading knee deep in the bullsh!t to find those few great threads that offered a lot of fantastic information to learn from... but those seemed to get more and more rare as the BS threads became more popular. Every once in a while I stroll in there, but for the most part I try to find answers in other places.

 

yeah, SD rejects seem to be flooding car sound now. The quality of posts have definatly gone down. Although the thread on Adire's new motor technology was rather informative and extremly funny.

 

hmmmm.... well i really dont know how to start this but here goes...... okies jim you may have your equations about everthing that you think about subs, but if you think (OR KNEW) that to get the best quality of sound is through frequencys , multiple frequency , a 15'' sub will not produce the exact frequency that a 12 or 10 will so if you think about it a set of all sizes will hit EVERY frequency giving more sound regardless of if you have 50 or 4 subs, second...... i didnt ask what your specs are on what i asked "has anyone ever seen 4 subs of 4 differnt sizes" i just plainly asked if anyones ever seen it, as for the shop no offense everyone im goin to sit here and try to list every friigin detail about it, just cuz i didnt say anything else dosent mean i know what im talkin about. and soon i will show you when i have time to do my **** and not everyone elses. being different is the spice of life and all i wanted to know if anyones seen it...... and in addition has anyone every heard of splash, if you can explain it then post it....

 

**waits eagerly for Jim to post**

 

im certainly not on the same level of knowledge as jim, but im pretty sure the logic behind why he says it wont work is this.. certainly a 15 does not produce the *exact same* frequencies as a twelve, but they *do* overlap quite a bit.. and the overlap is where you'll have the cancelling.. so while you may be covering a lot of frequencies, its very inefficient to be using so many drivers to do that, since probably 90% of them will be cancelling each other out.. i think im sure jim will be along shortly to dissipate everything i just said, but oh well.. i havnt gotten around to learning my one thing for the day yet

 

if you have 4 15's overlaping or 4 12's or 10's that overlapping causes your distortion making it shound like carp whatever you run but if you balance all the subs out than youll hit...... mama gates has alot more than 4 eq's...........and also thats "HIS LOGIC" not proof

 

also overlapping is not "HITTING"

 

comparing alma's setup to the one your are proposing is rediculous....

 

how the hell do you figure... she has a buran .....ok how much cubic space it that compared to a bird? lets think about it a second

 

I Know its apples to oranges........But I can see how like 2 8's and 2 15's would sound good. I mean with good crossovers and stuff, but dont get me wrong im not saying it would "win anyone 50 g's" .

Or no?

 

Okay, even though I completely agree with Jim's reasoning on this, the only question I have is this....

Why the he|| is this information explained on a hardware / overclockers website in such detail???


Oh well...

:lala:

 

I'm sorry, was my first description accidentally written in french, or do you just have no idea what I actually said? I'm not sure what your frequency babble is about here, but the point I was making is that because the frequency response and the overall sound characteristics of the subs are different, if you try to have them all play the same portion of the audible spectrum (you still with me chief?), what results is a non-favorable blending of the sound, which translates into sh!tty sound. If you use a half-dozen crossovers to direct the different frequencies to different subs, you wind up with a whole mess of phasing problems, plus any time you cross over two different drivers, you are once again faced with having two different drivers playing the same frequencies, and how well they blend will have a very direct impact on sound quality. This is why the vast majority of SQ cars have a very, very, very simple setup, usually with no more than 1 set of subs, and a 2 or 3 way component system.

I assume you mean ALMA Gates? I'm sure the car has plenty of EQs. What's your point? When it is set up for SPL, that Bronco has a frequency response of 59.5 to 60.5 hz. Well, I don't know that 60hz is the center frequency, but my point is, that bronco has an extremely, extremely, extremely narrow bandwidth so that absolutely no power is wasted.

I can't even figure out what the f*ck you're saying here, but it sure isn't what I said. If that's what you think I said, then you're doing a great job of helping me prove that you don't know what the hell you're doing.

Never heard of it. I guess that officially makes me a dummy. Are you really trying to resort to a terminology pissing match? You don't want to do that.

This thread is becoming a waste of space. It was good for a while because there was some good technical content, but now I'm just repeating myself for the sake of proving somebody wrong.

 

HELLZ YEAH JIM :hail:

 

Does Kicker or MTX hold the SPL world record? all i know is i saw a 91 camaro, when i was searching the web a while ago, with 22 or 24 12's in the back (where the seats are). In my opinion its pointless but it was amazing. Im 17 and curently taking electronics classes and from my understandings SPL rating comes from the angles of sound waves not really how many subs you have. Like if i wanted good sound quality for my car i should get rid of the 4 by 6s in the front and put kick panels in for the correct angle for the sound waves....now if i was going for SPL i would leave them in b/c the sound waves would bounce off the window makeing SPL rating higher. SO...yes i have seen Third Gens with many subs and different sizes....but does more subs mean more SPL im not really sure i thought it was on the angles so hmmm.. just my young .02 lol

 

Ok, i have one thing to say.

I noticed threads like these get alot of "spl is pointless" type responces.

Why is that ? Because you can't listen to it and enjoy it ?

Is builging 6 second dragster pointless then ? It's not like you can drive it on the street and enjoy it.

Ok , 2 things then.

sorry to say, but I don't think the f-body is a good platform for ultra high spl. My sponsor built a spl civic a few years back with 4 Kicker solo 15"s. Proplem was, the car had a sun roof, and even at 158 - 160ish, it would push the sunroof up about 1". now, the f-body's door windows do not sit in anything to hold them against the vehicle, they kinda just sit against the weather stripping (you know, no upper door frame). I find it hard to believe a f-body is going to break 160 without pushing the windows out a bit.

F-car is great for moderate SPl, infact, I get high 140's with 2 10's in my wife's Z. But for 160+, I just don't see it happening.

mike

 

LMGDMFAO at this thread.

 

Anything is possible is all i have to say on this board....This guy that owns a stereo store in Bethlehem (i live in PA) had the loudest Trans AM on the east coast it was wicked...the shop is Atomic Audio.

 

The thing is that if you're going for pure SPL you only need to hit one frequency for a short amount of time and as efficiently as possible to produce the highest SPL possible. Think of it like this:

1. First situation: Your theory is that if you have all sizes you will hit every frequency and have more sound. Let's take a water hose that is unfocused and has a lot of volume of water flowing through it and hitting a large area. Now, there is a lot of water flowing, and it is hitting a lot of areas, but it's not hitting them with much force.

2. Second situation: You take that same hose. Let's take the same volume of water again, but this time let's focus it all in one small area. You have the same volume of water flowing, but thsi time isntead of hitting a lot of areas with little force, it's hitting one area with a lot of force. You don't need to hit all the other areas to gt the result you want.

Now, I know water and sound are very different, and the way they build pressure is very different, but I think this analgoy is helpful.

If you're going for SQ, than it's already been explained very clearly why it would sound like ***.

If you are going to blast someone's logic, you had better have solid proof to support your view. You haven't provided any proof of what you're saying, only questionable logic on your part. So how can you try to discredit Jim by saying he's only presented logic?


Also, if you want us to begin taking you seriously, start using punctuation. Go over your posts a little bit and make sure they make sense before pressing post. That way it won't look like a monkey found a keyboard and started typeing. If however, English is not your native language than I apologize in advance, because I know it is very difficult to learn.

 

 

Trans_am_racing, your reasoning does not make since. You are saying that a 15" sub reproduces one frequency and a 12" sub reproduces another. Then you are going on (if I understood this correctly) that if you have two 12" subs you are only playing one frequency or "overlapping?"

The fact is that a 12" sub reproduces every sound a 15" does (for the most part) except does so differantly. With your setup of 4 sizes of 4 subs or whatever...the same frequencys would be played but each size of sub would play it differantly causing your ear to pick up the same note played differant ways and the reason for a ****ty *** sounding system...or my one 10" Memphis SHP will sound better (when I get the money that is).

-Matt

 

I like PIZZA!!!!:lala: :lala: