Bass is nothing like it should be

[CadillacMatt 31]

So I got my 2 Q 15's installed in the box (7cuft @ 32Hz), running off an AQ2200D, and installed my 36sqft of Damplifier Pro (great stuff FYI) but I seem to be having a problem getting the bass into the cabin. I knew that I'd probably run into this problem with such a big box so I'm weighing my options now.

The box is rear facing, and when I pull it within about 6"-8" from the back of the car the bass seems to be the "best", but I still have limited clearance around the top and sides of the box. The bass sounds extremely peaky at higher frequencies (60-80Hz) and I believe this is because the trunk is actually functioning something like a double vented bandpass and blocking most of the lower frequencies from passing through. The only openings into the cabin are a small triangle section in the middle of the back seat, and the two holes where the 6x9s used to be.

I am thinking of cutting a hole in the rear deck to port the trunk, something like 6" x 24". I removed my 6x9's (the compression from the bass blew one of them so I need to come up with a different solution there anyways). Do you think this would have a better effect on the bass, giving it a large area to come through? Below are some pics of the temporary trunk setup (until I order my carpet and the rest of the Damplifier to make it purdy ) Thanks!

BTW - jon if you read this maybe we can meet up and you can check it out, lol

Edited November 17, 2008 by CadillacMatt

[jonbearsmt 919]

i think you have another problem.. i would wait befor cutting any thing!

you say that box is 7 foot.... now is thT 7 FOOT BEFORE SUB AND PORT? or after sub and port....

[CadillacMatt 31]

i think you have another problem.. i would wait befor cutting any thing!

you say that box is 7 foot.... now is thT 7 FOOT BEFORE SUB AND PORT? or after sub and port....

7cuft Net I believe... box was designed by F/C.

[jonbearsmt 919]

have you tryed moving the box closer to the tail lights?

and double checked all your cross over settings on your amp and headunit?

[RobClay 20]

whats your lpf,gain, and subsonic set to?

[CadillacMatt 31]

have you tryed moving the box closer to the tail lights?

and double checked all your cross over settings on your amp and headunit?

I've experimented with moving the box all the way back, and the bass response starts to get worse (like all of the energy is focused into the hapless sheet metal on the trunk lid, lol). I set my gains with a DMM originally, with everything set flat on the HU using a 50Hz test tone @ 0dB. I plugged the speakers back in and the bass was actually worse than my Xplods . So I boosted a loudness curve slightly in the meantime and it helped out a bunch... sooooooo I'm a little skeptical of the DMM method.

The crossover on the amp is set at around 85Hz, subsonic at 30Hz (go lower maybe?), bass boost OFF, gain about halfway (set with DMM). On the HU the Bass Boost is OFF, Loudness is OFF, Sound Retriever is set at "1" out of "0-2" (some sort of EQ booster that boosts the highs and lows), Sub LPF set to 80Hz, SLA set to 0.

Edited November 17, 2008 by CadillacMatt

[jonbearsmt 919]

i would turn the loud on... sla +4 50 hrz on the sub output.

did you check your ohms at the amp and besure your ohms are where you need them.

you know im just up the road if you wanna head this way

[jonbearsmt 919]

is that your sub speaker wire in the pic? what is that 12 gauge?

[RobClay 20]

set your lpf at about 60 also

Edited November 17, 2008 by RobClay

[rushnrun 14]

rough numbers.....

my guess is that you're box is roughly 5cubes net after all displacement, tuned at roughly 45hz...

looks to be about 40x18x20ish

with a 8x16x20ish slot port....

measure out the box and port dimensions....

unless that box is like 30 inches deep I don't see it being tuned any lower than 40hz... if it was 30 deep it'd give you about a 35hz tuning if my estimates are close.

[jonbearsmt 919]

that box looks small to me... but thats why i was asking you the cubic squestions

[CadillacMatt 31]

set your lpf at about 60 also

On HU or amp?

i would turn the loud on... sla +4 50 hrz on the sub output.

It makes it **MUCH** louder when I adjust ANY of the settings (be it EQ, Loudness, SLA) but wouldn't this defeat the purpose of setting gains in the first place? I don't want to blow these things up man

And besides the louder it gets the more sheet metal I hear rattling and less actual bass in the cabin...

did you check your ohms at the amp and besure your ohms are where you need them.

Did not check with DMM but I can do that... the subs are 1 ohm DVC, and their voice coils are wired in series for a 2 ohm load per sub. The subs are then wired in parallel to the AQ2200D for a final 1 ohm load.

is that your sub speaker wire in the pic? what is that 12 gauge?

Well, it's actually 18ga (waits for a slap) but I used the wiring speaker calculator on the BCAE website and it seems to be working fine... the distance is so short I don't think it's hurting anything (correct me if I'm wrong, lol!)

you know im just up the road if you wanna head this way

Maybe you could shoot me your phone # in a PM, I'm going out to eat with the GF tonight but I definitely want to get together with you sometime soon, whenever it's best for you bro (I work 6a-4:30pm M-F, so my nights are usually free). Thanks!!

[CadillacMatt 31]

rough numbers.....

my guess is that you're box is roughly 5cubes net after all displacement, tuned at roughly 45hz...

looks to be about 40x18x20ish

with a 8x16x20ish slot port....

measure out the box and port dimensions....

unless that box is like 30 inches deep I don't see it being tuned any lower than 40hz... if it was 30 deep it'd give you about a 35hz tuning if my estimates are close.

29 3/4"d x 17"h x 39"w

Port Length: 25.75"

Port Width: 6.5"

Port Height: 15.5"

Port Area: 100.75sqin

And like I said this box was built EXACTLY to spec as designed by Chris at Fisher Customs...

Edited November 17, 2008 by CadillacMatt

[stealth 113]

i would turn the loud on... sla +4 50 hrz on the sub output.

did you check your ohms at the amp and besure your ohms are where you need them.

you know im just up the road if you wanna head this way

adjusting his sla will only make his amps clip faster

[jonbearsmt 919]

im free most times... im on on call 24/7 so i just cant leave the city limits evenings and weekends are fine for me...

18 gauge!! i run 10 gauge power wire for my subs... and its only 2 foot from my subs....

i have never belived in setting amp gains with a dmm... thats just me...

watch and listen to the subs for stress.. they will talk to you to a point...

i allways set my h/u first... then roll my gain up on my amp slow... as i make little adjustments.

remeber to allways keep your bass in - on your h/u

[CadillacMatt 31]

remeber to allways keep your bass in - on your h/u

???

[jonbearsmt 919]

i would turn the loud on... sla +4 50 hrz on the sub output.

did you check your ohms at the amp and besure your ohms are where you need them.

you know im just up the road if you wanna head this way

adjusting his sla will only make his amps clip faster

if the settings are crazy....

i dont think it will MAKE it clip... i agree that if its +4 and the amp is adjusted along with it...

like i said in my post tho....

I WOULD..............

[RobClay 20]

On HU or amp?

on your amp

[akjay907 0]

what kind of car do you have?

[akjay907 0]

what kind of car do you have?

[KU40 173]

Try turning your box around and firing it into the cabin. In that case it would be even better if you could seal off the trunk behind the front baffle with some extra wood or the like. The box may be acting as a barrier in itself for the sound because it's so large.

[CadillacMatt 31]

what kind of car do you have?

1995 Cadillac Sedan Deville

Try turning your box around and firing it into the cabin. In that case it would be even better if you could seal off the trunk behind the front baffle with some extra wood or the like. The box may be acting as a barrier in itself for the sound because it's so large.

I thought about this option too but in all of the experiences I've had it's actually made the bass less intense (more mechanical noise and less actual bass is what I'm trying to say) but I need to put handles or something on the box first, lol (it weighs about 130lbs with woofers inside).

[KennyC 0]

When setting the gains with a DMM I always use the settings I will be listening with (or the most that the sub will see). I.E. Generally the sub is at +2 when bumping and my equalizers are already set to what I like. This way you know how much your sub is getting in comparison to setting it with everything flat and off and then turning it up after the gain.

Granted, this probably won't make a change with your situation..just a little advice.

Also Subsonic should be dropped a bit if you're looking for lows. With that amount of power and enclosure size you shouldn't have to worry about bottoming those subs out anytime soon. I keep mine at around 15 or so and never have any problems with bottoming out...but as usual every situation is different.

[CadillacMatt 31]

Subsonic should be dropped a bit if you're looking for lows. With that amount of power and enclosure size you shouldn't have to worry about bottoming those subs out anytime soon. I keep mine at around 15 or so and never have any problems with bottoming out...but as usual every situation is different.

Yeah I was a little unsure what to set the subsonic at... should I play a real low test tone and turn it down until it's right, I mean, is there a correct way to do this or just a general setting I should use (i.e. a certain # of Hz below your tuning freq).

[justin smith 0]

thats weird because i got a 7.4^3ft monster in my grand marquis and it murders the lows very much to my liking but igot sb up port back drver side