I'd like some opinions.

 

i have an 81 cadillac seville and i'm putting a system in and would like some other poeple's opinions. i was looking at putting three 10" audiobahn high excursion 600 watt rms subs in a sealed box. I just went to a local audio store and was reccemended some alpine 12" type r's. i listen to all types of music. if you reccemend another speaker please share your input. i would like to stay away from anything higher than a 12" sub.
 

hiphopanonymous
in a caddy? man you should be stuffin that thing with 15's man. but if u prefer 12's, then alpines are good, i mean great, if u have the dough.
 

Robert Farm
thnx hiphopanonymous i don't like 15"s because they have a long recoil time and i like all types of music. but i really want to bump. plz wrtie back
 

Anonymous
look 15's are going to be better than 12's any way you put it as along as they are the same line of sub. A 15 will respond just as fast as a 12 it simply has to move a smaller distance to create the same amount of sound. It can also play lower which will be nice since you listen to many different types of music. Also since you will have a good amount of space i would put them in a ported box they will play better at the tuning frequency and will be able to pound when you turn of the volume. Also i don't care for Alpines subs but its just personal opinion. The rockford Power HX2 15's play loud and have good sound quality at all volumes in a ported box.
 

hiphopanonymous
i agree w/ anonymous. fosgate 15's are nice. i currently am running 2 15's he2 subs in my ack legend and it's tearing everything apart. my trunk sounds like it's gonna fall off and my interior rear deck hella vibrates. other than all this crap, 15's sound way nicer than 10's or 12's that i have had in the past. 15's will REALLY bump! period.
 

"look 15's are going to be better than 12's any way you put it as along as they are the same line of sub."

not always.

"A 15 will respond just as fast as a 12 it simply has to move a smaller distance to create the same amount of sound."

not true. a 15" has more mass, and as the laws of physics tell us, the more mass and velocity, the more momentum, and objects in motion like to stay in motion. getting them to stop and go the other way, several times per second in fact, is more difficult with a higher mass. a fifteen is slower than a twelve, which is slower than a ten and so forth. remember, the frequency that the sub has to move back and forth is the same. the frequency is determined by the source material (music) whereas the excursion (amplitude) is determined by volume.

"It can also play lower"

true. the Fs of a larger driver (diameter) is lower due again, to the increased mass of the speaker. Lower Fs equals more resonance, or as you say, playing deeper.

"Also since you will have a good amount of space i would put them in a ported box they will play better at the tuning frequency and will be able to pound when you turn of the volume."

This is the drawback to a 15" sub. they take a LOT of box space. Now, going ported over sealed will yield a +3dB gain in SPL at the tuned frequency, but keep in mind you're also adding coloration to the sound by using a ported box as well.
a sealed enclosure will roll off at 18dB/octave, but cabin gain will compensate for that giving a nice flat response all the way down to below 10Hz.
If you're into accuracy, and you have the power to throw at the subs, sealed is the way to go. ported enclosures are a cheap way to get more SPL really, at the cost of SQ.

I agree with not being a big fan of Alpine's subs, but I'm not big on RF either. I'd go Adire, Onyx, DD, MMATS, or similar myself.
If you want deep, look at the Cerwin-Vega Stroker 15" or 18" too.
 

Anonymous
what do you guys think about a pair of JBL 12 inch 400 watt rms subs, and a JBL 1200 watt 2 ohm amp ?
 

zacdavis
well put glasswolf
 

The JBL BP1200.1 is a very nice amplifier, and well worth the $285 or so that it sells for.
I'm not as big of a fan of JBL's subs. Look at elemental designs perhaps (edesignaudio.com) or Kicker CompVR subs.
 

Anonymous
Hey thanks GlassWolf i was that anonymous you made look like a moron but thats cool. Im mostly self taught besides my cousin whos going to college for PA audio. if you could id appricite if you could answere a few questions i have. First you sayed that a 12 or 10 will respond faster than a 15 okay that makes sence because most subs including RF have the same size magnets for 10's - 15's so the same force acting on the smaller mass of the moving 10in cone will be able to respond faster. But it seem to also make sence to me that if you compare the suface area for the drivers a 10 will have (im excluding the suround and other variables since it doesn't matter as long as we are talking about the same line of sub)
say 78.54 in. squared of area (PIE x Radius or 5in squared). but a 15 end up with 176.72 in. squared of area. Over 2 times the suface area. Which correct me if im wrong should mean that to get the same output the 10 will have to move 2 times farther than the 15. So back to Einstines Principle so this means that the 10 smaller mass of the 10 will have to move 2 times faster to go 2 times farther than the larger mass of the 15. So the smaller mass of the 10 will be going 2 times faster and take a fare amount of energy to stop and return before hitting again when the 15 has to stop the larger mass but its not going as fast so will not take so much energy it sound like a trade off.
 

Ok firstly, magnet size being larger doesn't mean the sub is better. Magnet material plays a large factor as does driver design. Also you can have a magnet be too large, which leads to something called over-damping. This isn't good, so be wary of companies who try to sell you on bigger is better theories for magnet structures.
I didn't intend to make you look bad by the way. Sometimes I just come across as a bit superior I guess, since I'm used to teaching this sort of stuff to people, and I never know how much they know when I start, so I try to be thorough.

Ok as for SPL, remember, the speed that the sub moves (frequency) is determined by the music being played. If the music is sending a 50Hz signal to the subwoofer, then the sub has to travel back and forth 50 times per second, regardless of diameter.
As for amplitude (distance traveled to produce the same SPL) you're correct, that the 15" sub would not have to excurse as far as the ten to produce the same volume. SPL is generally determined by two factors. Xmax, and cone surface area.

I actually enjoy this sort of conversation. It's much preferred to the name-calling that seems to prevail around here in some threads.
 

im the anonymous you've been talkin to i just decided to make name for myself. okay that sort of makes sense but there have to be alot of other variable that greatly effect spl.
Now lets me see if i have some of these straight: efficency at the standard 1W 1M only effects how well the power is used? say there is a sub with 95 db efficency that handles 500 watts continuous, compared to another sub that has a 92db efficency that handles 1000 watts continuous. they will have the same output at there maximum power handleing???? if so that would mean that my audiobahn Flame Q 12's that handle 1100 watts continuous and are 96.4db 1W 1M ,should be much far louder than my RF Power HX2 15's that handle 1000 watts rms and have only 88.6db 1W,1M. i don't have the amps yet to bring them both to there full volume so i don't know yet but am i correct? if so i would think that would mean any company trying for a sub designed just for SPL then all they would have to do is make it handle lots of power and be very very efficient. it seem far to simple to be true.
 

yes other factors greatly affect SPL, but as for the sub itself, those are the two factors.
you also can figure in vehicle damping, cabin volume, box type, etc, but those aren't things that are a factor of the speaker design itself.
external variables if you will.
ehh efficiency is a tricky spec to use in real world means. it's really only an effective spec with power ratings below about 100 watts and as you noted, it depends also on other Thiele-Small specs as well. specs can be very misleading and generally, aren't a good way to masure the worth of a sub, alone.
you're also right that this summary is far too simple to be used for such calculations. Look at the specs on the 13W7 JL Audio subs, as an example. Audiobahn doesn't have anything that would come close by real world comparison, but they try to say they will if all you do is read spec sheets. there are many subtle factors that need to be considered when you look at the actual performance of a particular sub.
 

loud and low
so how can you get a good idea of a subs real world performance without hereing them??? My cousin told me the same thing he sayed that wiht the high power subs efficiency isn't very important. WHY? i don't understand how more power or power over as you sayed 100 watts changes efficiency?? Also in the next few years im looking into selling all my stuff and buying some sound quality subs (15's or 18's) price doesn't matter as long as its under 5 grand for the subs and i want a good sound quality amp. My cousin has a older Presion Power setup, he has 2 15's that were apparenty hand made they were never for sale in quantity and he competes only in sound quality competitions. What brand to you trust or recomment most. to anyone else im talkin to glasswolf, please if you don't know your stuff don't put some stupid comment like sony, thanks
 

a lot of trying to expalin the mechanics of this would assume that you have a fairly good understanding of electrical engineering, which I am not going to assume you have. Short answer is that the best way to judge any speaker is to listen to it, or read up on it in unbiased reviews by professionals. Sometimes you can just go by company reputation. Certain companies are known to have good equipment, like Kove, JL, Sinfoni, McIntosh, etc in car audio, like Krell, Martin Logan, KEF, or Mark Levinson do in home audio. when you buy from these companies you know the product is good, and the specs are accurate.
part of the problem with judging based on specs, is that specs are very misleading, since many are measured in different ways, and the way they are measured isn't often advertised.
a few examples:
THD. THD has two main ways to be measured. FCC or EIA standards. one uses a full 20Hz-20KHz sustained pink noise signal to measure THD, whereas the other uses a burst signal at a notch frequency to yield more pleasing results.
Xmax: some measure peak to peak excursion, whereas others measure peak to center.
Power handling: RMS (continuous), or max?
...and the list goes on.

ok as for a SQ setup, you may want to go with twelves instead of 15 or 18 inch subs. for SQ, a ten or twelve is just going to be a lot more responsive. PPI's original Art series products were fantastic, and still some of my favorites. Sadly, PPI was later bought up and moved overseas, and now their products are rather lacking.
If you want some good sub companies to look into, try:
Kove Audio
Digital Dynamics (DD)
MMATS
Resonant Engineering (RE)
JL Audio 13W7
Adire Audio
Onyx Mobile Audio

good amlifiers:
older Orion HCCA and SX series
older PPI Art series
Zapco
Sinfoni
US Amps
McIntosh

Head Units:
Eclipse
Alpine F1Status

Signal Processing:
Zapco
Audiocontrol
USD

Components:
DynAudio
USD waveform guide horns

those are the best products you'll probaly find for car audio, bar none. None of them will be cheap though.
the companies above are my personal favorites, and generally the sort of stuff I try to use in my own vehicles.
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