ok my and my friend are in the process of puttin four 15" volfenhag subs in my firebird. they are rated at 1200 watts a peice, and i think 600 watts RMS. i want to get the best amp i can. my goal is to hit atleast 150-160 db. i was thinking about 2 fosgate amp's model #700s, 2002 Punch 700S. 175x2 @ 4ohm - 700 watts RMS total. i would like to know if you have any other sugestions on amps, or you have any other ideas on what amps to use for these subs.

 

you were looking to get 2 175wx2 amps? that's barely gonna move those 15"s... you have to get 2-2channel macho amps.. like 600-800wx2... or even 4 - 600wx1. In the audio world.. after a certain amount of quality, in order to upgrade, cost jumps immensely. 4-15"s is a big step...and by that i mean powering them.

 

150-160? you're asking a lot out of those subs. and just because you MIGHT be moving enough air doesnt mean you'll get the SPL. our cars arent the greatest for high pressure levels. yes, the hatchback design is great, but the lack of an upper window support (the upper door frame we lack) can allow air to escape out when the windows flex outwards. if you've got a hardtop, the roof will flex too and who knows what other body panels. expect to do a lot of sound dampening too. i also really dont know if those subs will do it for ya either, but good luck. amp wise, look for either a jbl 600.1 or 1200.1. both are inexpensive and can push quite a bit of power

 

ok. thanx guys...i think putting 4 n there would be overkill....but not out of the question, but i might just go with 2. but thanx again.

 

if you are looking for some serious power, look at audiobahn, kicker, jbl, and my favorite JL AUDIO... good luk :lala: :lala: :lala: :lala: :lala:

 

Let's not forget the limited amount of airspace you have when putting a box for four 15" subs in the rear. Unless you're gonna remove the back seat.

And it takes A LOT of power to get up past 145. I mean A LOT!!!!!! 700 watts per sub is likely what you'll need.

I've hit 135.5 dB with one 12" MTX 3000 with a Punch 100 running it. That made me proud because that was an 8 ohm sub and a dinky amp.

There's a rule of thumb that's good to follow. For an audible increase in SPL, it takes +3 dB. On average it takes TWICE the power to achieve +3 dB.

Using the setup I had as a reference, it would take 5 times as much power to reach 150dB. Since I was only using the RF Punch 100 I would need 500 watts of clean power. That's not taking into consideration all the extras I'd need to run something like that. Plus I'd send the woofer thru the hatch. So I'd have to buy a better sub.

The unfortunate thing is for a sub to be able to handle that kinda power, it normally sacrifices Sensativity. Example... that MTX I had was rated at 90dB 1w/1m. The average "monster" sub is around 87-88db 1w/1m. That's about a 3dB loss right there. Guess what....... Now I need 1000 WATTS!!!!! to get to 150dB.

That's not taking into consideration that I could just add another sub. But it's still a comprimise. My Punch would then put out 200 watts bridged (+3dB), and each sub would get 100 watts (same as the one sub was getting), and one extra sub averages +3dB. So that puts it closer, but still not there.

If I added two subs to that, the power would simply split between the subs. If I added two more, then each sub would only get 50watts, which is -3dB per sub (or -6dB total), but adding more surface area from the other two subs would bring it back +6dB. So it'd really just be even. Now it's time for more power!!!!!!! I'd need 2000 WATTS to get +3dB. And after all is said and done, I'd be right were I said it's hard to get to...... ~144dB.

It's not a very fair game is it? But if you try I hope you succeed.

AJ

 

yeah, fitting 2 12" takes up all the well, i cant imagine properly fitting in 4 15s. too much space taken away for me. plus i like to keep it simple and hidden. hopefully most of you wont and havent found out why having an fbody and a system is not always a good combination

 

well i started the box this afternoon..its right where the back seat used to be. its alll fiberglass and i plan on having 2 subs right behind the driver and passenger seats..i think having 4 in there might be too much but its still not out of the picture but for now its just 2 15's, and with the set up im doing right now i can still bring my t-tps along with me and still be able to use the well area..but fornow im trying to finish this box..hopefully ill be finishing it up next sunday..hopefully..and maybe ill get atleast the subs in by the following weekend if not sooner..and then the amps..

stevo.