# Subs and Rear Speakers



## Sentra5646 (Jan 2, 2004)

I just put in 2 kappa perfects and i put a pair of infinity 6.5s in the rear deck. My subs push my speakers up and are making them pop because of it. What should i do. A local store told me that people use plastic bowls to seal off the rear speakers. The trunk bar thing is in the way though. It seems like anyone in a b13 chasis would have this problem with subs because of the way the speakers are designed. But please help if you can. Thanks.


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## danifilth (May 14, 2003)

you best bet is posting in the audio section.


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## sno (Oct 4, 2002)

i don't have that problem. i purposly used speakers that were too small for the holes in the back deck so that air from the subs could move past the speakers.


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## SentraFourplay (May 11, 2004)

I installed 6x9's in my rear deck (with a bit of metal cutting) and I have tow xtant subs in the trunk with no problems. As far as the trunk torsion rod things all I did was took a piece of 2x4 and wedged it inbetween the rods and the trunk roof and that made way for the 6x9 magnets and you cant see the wood anyways.


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## tomd (Oct 18, 2002)

are all the speakers in phase? meaning, all the + are + and - are -, because if they aren't, could cause cencelation, or waht you are describing, with my subs and infinity kappas, no problems with popping (that i've noticed in the past year).


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## Philippe (Feb 5, 2004)

*toss'em*

The plastic things are called baffles. I can only find them instock at custom audio shops. They come in plastic and foam. I had a similar problem. My sub is a single 10" in a ported box and my back speakers sounded like garbage so I took them out and I don't miss them at all. Up front I have a kappa components and It sounds great. Driving towards the highs with the lows massaging your back.


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## glowsentra (May 27, 2003)

Dynomat speaker insulation might help, you could custom fab those bowls using common materials, and use the dynomat over them....


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## LimitedEdition (May 31, 2004)

I just installed a 1400watt Power Acoustik SQ-10 powered by a 520watt PA amp. I don't have the problem with the deck speakers, but man 'o man was that 3rd brake light dancing. Nothing a small peace of vacume hose couldn't fix.


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## sr20dem0n (Mar 19, 2003)

Yeah that's from the pressure in the trunk, some people have had their rear speakers completely destroyed because of it (tore the surrounds completely apart). Not much you can do about it at all. In order to do anything about it with a baffle, you would have to get something strong and COMPLETELY seal it to the rear deck, otherwise it wouldn't make any difference. Well by doing that you basically make super small sealed enclosures for your rear speakers, which will cut the efficiency down a huge amount and cut nearly all your low frequency reproduction. I say just remove the rears, the holes let the sub(s) breathe into the cabin anyway and it will noticably increase your spl.


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## Winterz (Jun 3, 2003)

Well, what you could do is put a port behind your back seat cushion, and force all your sub air flow through it...Don't cut all the way through the seat, just enough to get past the backing. Chances are high nobody will notice when sitting back there, except for the back rub with bassy songs. make sure it's pretty big PVC or you'll get some port noise. 5" should do the trick.


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## sr20dem0n (Mar 19, 2003)

Winterz said:


> Well, what you could do is put a port behind your back seat cushion, and force all your sub air flow through it...Don't cut all the way through the seat, just enough to get past the backing. Chances are high nobody will notice when sitting back there, except for the back rub with bassy songs. make sure it's pretty big PVC or you'll get some port noise. 5" should do the trick.



Don't do that, if you add a port through your rear seats, it will basically make your trunk a ported enclosure. With the sub in a box already, and inside this "ported" trunk, you will end up with some type of screwed up bandpass result. Holes are fine, ports are not


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## Winterz (Jun 3, 2003)

sr20dem0n said:


> Don't do that, if you add a port through your rear seats, it will basically make your trunk a ported enclosure. With the sub in a box already, and inside this "ported" trunk, you will end up with some type of screwed up bandpass result. Holes are fine, ports are not



Umm...nope.... a 5" port will have minimal, if any, accoustic properties in this set up. The resonant frequency (fs) of a 5" port is quite low, depending on length. The Rear deck speakers are already in a poor man's infinite baffle, the port (of this size) will not effect them greatly. Additionally, the seat cushion material is going to act as a baffle. There will be no "screwed up bandpass result", because the trunk volume is sufficient to have no audible resonant frequency (well, the trunk lid may resonate, but that's a different matter entirely ). 


All you're doing with a hole/port (doesn't really matter which in this instance) is allowing air to pass through the opening. In your case, you want as much air as possible to pass through the opening, so that your rear deck cones are not being forced to flex by the air movement of the subs.

Regards,
-W


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## sr20dem0n (Mar 19, 2003)

Winterz said:


> Umm...nope.... a 5" port will have minimal, if any, accoustic properties in this set up. The resonant frequency (fs) of a 5" port is quite low, depending on length. The Rear deck speakers are already in a poor man's infinite baffle, the port (of this size) will not effect them greatly. Additionally, the seat cushion material is going to act as a baffle. There will be no "screwed up bandpass result", because the trunk volume is sufficient to have no audible resonant frequency (well, the trunk lid may resonate, but that's a different matter entirely ).
> 
> 
> All you're doing with a hole/port (doesn't really matter which in this instance) is allowing air to pass through the opening. In your case, you want as much air as possible to pass through the opening, so that your rear deck cones are not being forced to flex by the air movement of the subs.
> ...


You never said how long you were planning on making this port. If it was an inch long you would be right, but the longer you get the more risk there is. Chances are there wouldn't be a problem if it was only 2-3" long (the length required to go through the rear seats), but just telling someone to port it with some pvc is a bad idea, because you KNOW some dumbass out there will put a 20" long piece thinking it would have some kind of funnel effect and make it sound better.


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## Winterz (Jun 3, 2003)

True.


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