Suggestions on "port" to allow more air from the trunk into the cabin in a sedan?

[bikinpunk 10+ year member]

Setup:

1000/1 & 12w7 in 1.9 cube, 27hz tuned, ported box. Trunk lid is deadened with 2 layers (probably will do one more later), and the rear deck (cabin side trunk lid) has one layer of deadener along with some foam stripping on the VERY edge next to the window to help with possible rattles.

My problem is that I'm having to turn up my bass on the h/u to 10/15 to get the sound I'm wanting. I used to run it at 6/15, but either the deadening on the trunk lid has hindered the process or my ears just aren't the same. I'd like to keep my rear fill since I *might* do 5.1 later and I quite often have riders in the back seat. If not for that, I'd remove them altogether. Is there something I can do to allow the air from the trunk into the cabin such as adding "ports" or some kind of blow through? If I have to, I suppose I could cut a hole in the rear deck, but I'm not sure what good it would do since the deck lid would cover it? I think I'm kind of at a loss here, but does anyone have any suggestions?

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[azbass 5,000+ posts]

im sure there are stock holes the rear deck that are open? if not open some holes up.

 

[jdawg 5,000+ posts]

take the deck off, cut big holes in it, then recover it

 

[HondAudio 10+ year member]

^ What he said above. I did that in my old Civic, even though the box was up against the back seat. The Civic had speaker "units" on the back deck. You undid some nuts from underneath, lifted them out from inside the cabin, unscrewed the grills from the underside of the unit, took off the grill, then unscrewed the speaker.

Put the grill back on, put them back in the rear deck, and you have a stock-looking rear deck.

It takes five minutes, and, hey, it's free. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[mattf 5,000+ posts]

I took my rear speakers out and took out the carpet on the rear deck. It made a huge difference from before.

 

[helotaxi 5,000+ posts]

He wants to keep the rear speakers, so it sounds like he and an airsaw, jigsaw, sawzall, or plasma cutter are goint to get aquainted.

 

[neonrt 10+ year member]

i removed all the stock deadener from my rear deck, replaced the carpet for a stock look, and my bass in the cabin improved dramatically. almost as good as the seats down. i have no deadener yet though, so that could be your problem.

 

[HondAudio 10+ year member]

I forgot to mention that I also put 2 layers of deadener on the rear deck, and cut it out where the holes existed in the sheet metal. It was a fairly strong, resonance-free piece because it was a key part of the unibody, and it had undulations and uneven stamping to make it have the anti-flex properties of fiberglass (which is strong on curves but flexible on large flat expanses).

 

[PowerNaudio 10+ year member]

Setup:1000/1 & 12w7 in 1.9 cube, 27hz tuned, ported box. Trunk lid is deadened with 2 layers (probably will do one more later), and the rear deck (cabin side trunk lid) has one layer of deadener along with some foam stripping on the VERY edge next to the window to help with possible rattles.

My problem is that I'm having to turn up my bass on the h/u to 10/15 to get the sound I'm wanting. I used to run it at 6/15, but either the deadening on the trunk lid has hindered the process or my ears just aren't the same. I'd like to keep my rear fill since I *might* do 5.1 later and I quite often have riders in the back seat. If not for that, I'd remove them altogether. Is there something I can do to allow the air from the trunk into the cabin such as adding "ports" or some kind of blow through? If I have to, I suppose I could cut a hole in the rear deck, but I'm not sure what good it would do since the deck lid would cover it? I think I'm kind of at a loss here, but does anyone have any suggestions?

well you sound deaden your car, which is a good thing, but now some of the panels that used to be invisible to sound waves and had some rattle are now absorbing the sound waves instead of letting them pass trough.

the good thing is that you still get the sound you used to!, by only raising the gain level on your player, which is not a real bad exchange since you get cleaner bass anyways. or are you getting distortion now, by clipping the cd player signal to the subwoofer amp?

have you tried raising the gains on your amp just a bit so that you dont have to raise the gains on your player as much, i know its just a band aid.

but it cures your gain issues on the player.

now if you would just like to gain the sound level you have lost from sound deadening your vehicle.

you can get an enclosure designed/built that will get you more spl from the current subwoofer and amp.

since right now its obvious that your enclosure was designed for SQ by tuning low. the same enclosure of 2cuft tuned to 33Hz on that sub will still get you a deep low end bass at about 3db increase 32Hz on up, yeah you'll lose a bit from 29Hz on down but it wont be that critical, it will be more of an improvement then a loss.

does your seat fold down?

are your subs facing the trunk or the back seats?

are the gains on your amp at 100%, 75%, 50%?

have you made any changes to the subsonic filter? like raising the level to 30Hz and above?

there could be other alternative to gaining bass in the cab cutting up your car and loosing resale value if you ever decide to sell the car.

 

[iamamp3pimp 5,000+ posts]

He wants to keep the rear speakers, so it sounds like he and an airsaw, jigsaw, sawzall, or plasma cutter are goint to get aquainted.

You forgot an angle grinder.

 

[bikinpunk 10+ year member]

well you sound deaden your car, which is a good thing, but now some of the panels that used to be invisible to sound waves and had some rattle are now absorbing the sound waves instead of letting them pass trough.
the good thing is that you still get the sound you used to!, by only raising the gain level on your player, which is not a real bad exchange since you get cleaner bass anyways. or are you getting distortion now, by clipping the cd player signal to the subwoofer amp?

have you tried raising the gains on your amp just a bit so that you dont have to raise the gains on your player as much, i know its just a band aid.

but it cures your gain issues on the player.

now if you would just like to gain the sound level you have lost from sound deadening your vehicle.

you can get an enclosure designed/built that will get you more spl from the current subwoofer and amp.

since right now its obvious that your enclosure was designed for SQ by tuning low. the same enclosure of 2cuft tuned to 33Hz on that sub will still get you a deep low end bass at about 3db increase 32Hz on up, yeah you'll lose a bit from 29Hz on down but it wont be that critical, it will be more of an improvement then a loss.

does your seat fold down?

are your subs facing the trunk or the back seats?

are the gains on your amp at 100%, 75%, 50%?

have you made any changes to the subsonic filter? like raising the level to 30Hz and above?

there could be other alternative to gaining bass in the cab cutting up your car and loosing resale value if you ever decide to sell the car.

does your seat fold down? yes

are your subs facing the trunk or the back seats? no

are the gains on your amp at 100%, 75%, 50%? 50%

have you made any changes to the subsonic filter? like raising the level to 30Hz and above? no

I increased the bass boost to +3db on the amp and it has solved the issue. I still keep the gain on the h/u @ 6/15 mainly for more "headroom".

I do have one question though. You said I get cleaner bass at full voltage from the headunit? I would assume that if you keep the gain setting on the h/u it would help the amp's life. Is this not valid?

As far as using the same volume with higher tuning, I've tried that and really didn't like it. I tuned to 34hz and it sounded horrible IMO. I like it tuned low and don't really plan on chaning unless I get a larger vehicle that would enable me to build a bigger box.

Thanks for the feedback. Probalby the most useful info I've gotten here.