Sealed box sounding bad. need some help.

[Amart88]

Hey guys, Just finished my under seat box for 2 Fi 10" ssd's with high qts option. Powered by an Ampere 2000.1

Just played for the first time and it sounds terrible... Very low volume sounds ok but when i turn it up, everything say below 40 hz sounds like I am playing below tuning on a ported. Just sounds muddy or distorted or like woofers are out of phase (they are not). 50-70hz is audibly way louder. There is also a lot of excursion for so little sound. As far as i can tell there are no leaks. The box is totally PL'ed, glassed and bedlined.

Fi's site says 0.2-0.4 cubes per sealed. I have around 0.5 cubes per net. That is the absolute max I can fit. I have the lpf set at 80hz.

I usually do ported but there is absolutely no room in this truck for it. Just spent a few days on this thing. and now I am kind of annoyed.

Thanks.

[DTS909]

How much space between seat and the woofer? Do the seats have the hard plastic bottoms?

[Amart88]

How much space between seat and the woofer? Do the seats have the hard plastic bottoms?

Woofers are down firing. About 1 inch from the floor. The seat is all carpet. I tried with the box standing up and with only one woofer. same result

[Esgedi]

Are they in a common chamber? High QTS drivers aren't going to sound stellareither way, but if they're in a common chamber they're probably throwing each other out of phase a ton. The reason they're so quiet is probably because they are a relatively inefficient driver that's been stuck into a small box, at best all you can hope for is low end reinforcement. Any idea what the FS is on the high QTS drivers?

[Amart88]

They are in seperate chambers. Not sure on high qts. fs. i heard it is not a huge change from normal

[Esgedi]

What amp do you have running them? Just curious.

[Skullz]

Did you use any polyfill or poly batting?

Often times a box will make noise that is louder than what the sub produces, and to combat that issue, you will need to line the enclosure with some poly batting or polyfill.

[Triticum Agricolam]

Are they in a common chamber? High QTS drivers aren't going to sound stellareither way, but if they're in a common chamber they're probably throwing each other out of phase a ton. The reason they're so quiet is probably because they are a relatively inefficient driver that's been stuck into a small box, at best all you can hope for is low end reinforcement. Any idea what the FS is on the high QTS drivers?

What? There is no reason higher QTS drivers can't sound good. There is no way the subs are "throwing each other out of phase", unless they are wired out of phase.

I agree with Skullz and the OP should try putting some polyfill in the box. I'd also suggest pulling the box completely out of the vehicle and trying it out. See if its something to do with the acoustic environment of the truck.

[Kyblack76]

Are they in a common chamber? High QTS drivers aren't going to sound stellareither way, but if they're in a common chamber they're probably throwing each other out of phase a ton. The reason they're so quiet is probably because they are a relatively inefficient driver that's been stuck into a small box, at best all you can hope for is low end reinforcement. Any idea what the FS is on the high QTS drivers?

What? There is no reason higher QTS drivers can't sound good. There is no way the subs are "throwing each other out of phase", unless they are wired out of phase.

I agree with Skullz and the OP should try putting some polyfill in the box. I'd also suggest pulling the box completely out of the vehicle and trying it out. See if its something to do with the acoustic environment of the truck.

Was hoping youd chime in and help.

He pm'd me on FB, and im not a box guy. Id think that box (sealed, with the fi q's) should sound hella good.

Would adding poly make it sub think its even in a LARGER box? I think hes losing some mechanical also. Why i bring that up.

[Esgedi]

Are they in a common chamber? High QTS drivers aren't going to sound stellareither way, but if they're in a common chamber they're probably throwing each other out of phase a ton. The reason they're so quiet is probably because they are a relatively inefficient driver that's been stuck into a small box, at best all you can hope for is low end reinforcement. Any idea what the FS is on the high QTS drivers?

What? There is no reason higher QTS drivers can't sound good. There is no way the subs are "throwing each other out of phase", unless they are wired out of phase.

I agree with Skullz and the OP should try putting some polyfill in the box. I'd also suggest pulling the box completely out of the vehicle and trying it out. See if its something to do with the acoustic environment of the truck.

QTS directly implies how good a driver is at being a transducer, turning power into linear movement. It's also VERY possible for two drivers in a sealed common chamber to be running out of phase, which is why i asked. I'm not talking about 180deg out of phase, i'm talking about a progressively going out of phase throughout the frequency and power range due to the standing and rearward waves hitting each other, essentially changing the suspension compliance of the driver. Every driver gets progressively out of phase throughout the frequency range unless you apply some form of correction filter device for it.

I don't see how polyfill is going the change the fact that it sounds muddy and out of phase since since the drivers are in their own chambers, all it's going to change is the speed of the rearward waves... but it's a cheap solution and everyone has some laying around, so no harm in trying it out.

Op, to me it sounds like you have one of the drivers wired backwards. I've corrected the same thing a dozen times and it sounds exactly like what you described. Let's hope that's it, because a 15 minute fix is obviously optimal.