Help with subs
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 6,097
Likes: 0
From: High Plains Drifter Fayetteville, AR
Ok, from some rudimentary calculations, the interior volume of the enclosure is .67ft^3. That doesn't take into account the displacement of the speaker assembly.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 6,097
Likes: 0
From: High Plains Drifter Fayetteville, AR
Resealed the woofer to the baffle last night and that made a HUGE difference. I also added a little more polyfill. Both of those together made the lower bass much louder than it had been. Now I have even more rattles to chase, lol.
Did some more searching and reading last night and it seems like the enclosure volume I have is right at the recommened volume for the ported eclosure and about double the recommended volume of the sealed enclosure. Would I be better off adding some material to displace more air and drop the volume of the enclosure? I was thinking that I could add some modeling clay or something like playdoh that wouldn't dry out and become hard and then rattle. Suggestions?
Or I could try to put a port in there. A 1" port ~1.5" long would give me a resonant freq of ~35hz. I just don't think I have enough room to put a port in there, but will look more closely.
Sounds good the way it is now, but we all know how that goes.
Did some more searching and reading last night and it seems like the enclosure volume I have is right at the recommened volume for the ported eclosure and about double the recommended volume of the sealed enclosure. Would I be better off adding some material to displace more air and drop the volume of the enclosure? I was thinking that I could add some modeling clay or something like playdoh that wouldn't dry out and become hard and then rattle. Suggestions?
Or I could try to put a port in there. A 1" port ~1.5" long would give me a resonant freq of ~35hz. I just don't think I have enough room to put a port in there, but will look more closely.
Sounds good the way it is now, but we all know how that goes.
Drifting
Joined: Sep 2004
Posts: 1,961
Likes: 2
From: Fort Knox
JMO, but Id doubt you'll get any more than a neglidgeable difference between porting and sealed. You can only get so much out of a pair of PA 8's. And im also willing to bet that those cubby holes arent 100% sealed, so they're already "slightly" ported by just air leakage...even if that is incalculatable. Im sure it sounds great the way it is. 
snoopdan
snoopdan
Racer
Joined: Jul 2001
Posts: 399
Likes: 1
From: Toronto Ontario
If the enclosure is too big, the alignment will be overdamped (low Q) and bass response starts rolling off at a higher than optimum frequency. Insulation makes the enclosure appear larger ( lowers the Q) so that would reduce output in the 45-70ish region. I sure it still sounds reasonably good because of the 12db/oct low frequency boost due the car interior volume.
If you want more low end, add a parametric or shelfing EQ and dial in 4-8 dB of boost at 20 or 30Hz.
I'd stay away from trying to port such a small box. The air speed through a 1" port will cause too much port noise. If you go with a larger port, you may not have room for the length required. That's precisely why most very small home subs use passive radiators.
If you want more low end, add a parametric or shelfing EQ and dial in 4-8 dB of boost at 20 or 30Hz.
I'd stay away from trying to port such a small box. The air speed through a 1" port will cause too much port noise. If you go with a larger port, you may not have room for the length required. That's precisely why most very small home subs use passive radiators.
Le Mans Master
Joined: Apr 2003
Posts: 6,059
Likes: 2
From: Texas
Originally Posted by vette_tweak
I'd stay away from trying to port such a small box. The air speed through a 1" port will cause too much port noise. If you go with a larger port, you may not have room for the length required. That's precisely why most very small home subs use passive radiators.
you will get nasty port noise with such a small port
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 6,097
Likes: 0
From: High Plains Drifter Fayetteville, AR
Thanks for all the help guys. I'll keep it sealed. When I feel like playing with it, I might try some things out to vary the volume of the enclosure and see what that does, but it sounds damn good for now.
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Also, try setting your HU bass setting and volume to 50% and then start turning up the gain on your amp "a little" at a time from 0 until you start hearing some decent bass. Turn up the volume a little more and listen for muddieness. If it dosen't sound muddy, then turn up the gain a little more ect. ect. Sooner or later you will have found the sound quality limit for your system. If it isn't loud enough for you, you'll have to add more or bigger subs and more watts if you still want to keep the sound quality.
It's easy to overdrive a little 8" sub with too much gain.
It's easy to overdrive a little 8" sub with too much gain.
