Polk Recommends Minimal Polyfill, How much?

Im adding a second sheet of mdf to the top of my box for my mm1040 svc. Just wondering how much polyfill I need? Should the box be half full, full to the top, bursting with polyfill?
Post edited by phil65 on
Comments
I would try filling it 1/3 to half way with densely packed fill.
Kenwood X595
Polk MM6501
Polk MM1240
Mtx 704x
Alpine MRX50
In my car
(1) corner loaded - firing towards back of trunk in the back corner results in lower bass but bad integration with mids.
(2) Firing rear - midway between seat and trunk lid is ok
(3) Back corner side firing to opposite side of trunk sounds best to me because there is really good low extension but I can get good upper end response to integrate well.
Kenwood X595
Polk MM6501
Polk MM1240
Mtx 704x
Alpine MRX50
Its mounted where its at due to lack of mounting options, still need my rear seat and leg room.
Kenwood DNX 5140
Arc Audio IDX and XEQ
Polk Audio SR6500 active and SR124-dvc sealed
Polk Audio PA500.4 and PA1200.1
Up pulls attention to the rear, and for some weird reason firing forward is usually the worst sound.
Polyfill won't give you more bass, it will actually reduce your efficiency. I suspect what you are lacking is more due to location and phase issues. Try reversing phase of sub if you haven't already
Kenwood X595
Polk MM6501
Polk MM1240
Mtx 704x
Alpine MRX50
Vital, im not really sure, ive heard of people doing it and that It helps reduce resonancies. Might just add the second sheet of 3/4 mdf to the top panel and be done with it.
If polyfill reduces efficiency what exactly is it used for? My understanding is that it makes the speaker think there is more volume in the box than what there really is? What does that do?
How much airspace do you have in your box?
Where do you have your gain on the amp set? What LPF are you using for the sub?
Is there not enough bass or is the bass muddy? What type of EQ do you have on the headunit? Are you sure its sealed properly? Leaks will kill the bass and cause noise.
Kenwood X595
Polk MM6501
Polk MM1240
Mtx 704x
Alpine MRX50
Dynamat isn't going to do jack to make 3/4 mdf enclosure stronger. It's just not made to be stronger then wood or add strength to it.
Adding another piece of wood will help with resonating since it'll make your box (or at least one side of it) stronger but sounds to me like your problem is something else. Answer questions asked by pentoncm, this should give us something to start with.
Where did you get this box from?? How much airspace does it have? Custom built? Got it from Best Buy? New/used???....
Kenwood DNX 5140
Arc Audio IDX and XEQ
Polk Audio SR6500 active and SR124-dvc sealed
Polk Audio PA500.4 and PA1200.1
After installing my speakers im pretty sure im going to have to dynamat my doors to fill in the 4x6" hole directly below the speaker, and the other holes around the speaker allowing the waves off the back of the speaker to come through, the mid bass definitely isnt there. Thanks for the help guys, you've really improved the install, as has some other members on this site, pretty awsome.