lydon Posted January 5, 2016 Report Share Posted January 5, 2016 Hi all, So recently I decided to go for a subwoofer and purchased an Infinity Reference 1262w (300w rms) and decided to build the box myself with limited woodwork skills. Being relatively new to the audio scene, Is 22mm (approx 7/8") plywood good enough, Is it necessary to double baffle the front side of the box? also, should I add polyfill to the enclosure? Note: Box is sealed Thanks! Link to comment Share on other sites More sharing options...
ckeeler11 Posted January 5, 2016 Report Share Posted January 5, 2016 7/8" is plenty think. most people use 3/4". not necessary to double baffle the front but would be better. no need to polyfil if box is built to specs. Link to comment Share on other sites More sharing options...
bman8891 Posted January 5, 2016 Report Share Posted January 5, 2016 ^ correct Link to comment Share on other sites More sharing options...
ShadeTreeMechanic Posted January 5, 2016 Report Share Posted January 5, 2016 If the box is sealed I would stuff it at least half to 3/4 full of poly fill and if ported I would line the inside with egg crate foam to keep it from sounding hollow. 91 C350 Centurion conversion ( Four Door One Ton Bronco) 250A Alternator (Second Alternator Coming Soon) G65 AGM Up Front / Two G31 AGM in Back Pioneer 80PRS CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon) Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon) Link to comment Share on other sites More sharing options...
lydon Posted January 5, 2016 Author Report Share Posted January 5, 2016 Thanks all for the feedback ! If the box is sealed I would stuff it at least half to 3/4 full of poly fill and if ported I would line the inside with egg crate foam to keep it from sounding hollow. Even if the box is built in accordance to manufacturer specs (box is sealed)? Link to comment Share on other sites More sharing options...
ShadeTreeMechanic Posted January 5, 2016 Report Share Posted January 5, 2016 From what I have read and my experience with poly fill, It prevents the sound waves inside the box from reflecting off of the back wall and acting against the drivers cone thus making it sound hollow. Egg crate foam in a ported box will do the same thing. I have seen recommendations based on studies that say one pound of poly per cubic foot. This also changes the compliance of the box so the box's resonant frequency is effectively lower. Some people use the amount of poly to fine tune the box frequency and can also help somewhat if the box is too small for the driver. I usually just fluff it up then stuff it half full. My 2 cents. 91 C350 Centurion conversion ( Four Door One Ton Bronco) 250A Alternator (Second Alternator Coming Soon) G65 AGM Up Front / Two G31 AGM in Back Pioneer 80PRS CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon) Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon) Link to comment Share on other sites More sharing options...
bmwking Posted January 5, 2016 Report Share Posted January 5, 2016 Thanks all for the feedback ! If the box is sealed I would stuff it at least half to 3/4 full of poly fill and if ported I would line the inside with egg crate foam to keep it from sounding hollow. Even if the box is built in accordance to manufacturer specs (box is sealed)? no need for filler if you build to manufacturer spec. Link to comment Share on other sites More sharing options...
MotorCityFats13 Posted January 5, 2016 Report Share Posted January 5, 2016 From what I have read and my experience with poly fill, It prevents the sound waves inside the box from reflecting off of the back wall and acting against the drivers cone thus making it sound hollow. Egg crate foam in a ported box will do the same thing. I have seen recommendations based on studies that say one pound of poly per cubic foot. This also changes the compliance of the box so the box's resonant frequency is effectively lower. Some people use the amount of poly to fine tune the box frequency and can also help somewhat if the box is too small for the driver. I usually just fluff it up then stuff it half full. My 2 cents. sound waves move slower through the fill so it increases the size of the box... if the box is built to correct size then there is no benifit to using polyfill.....also the fibers have to be able to vibrate so over packing it will just make the box smaller.... 1lb / cuft will yeild a box that thinks its 20% larger so this has to be figured in because you might not need 20%.... anyother physics from polyfill are pretty much void in most peoples uses Link to comment Share on other sites More sharing options...
Chris Braun Posted January 6, 2016 Report Share Posted January 6, 2016 Honestly I use polyfill in all of my boxes now. It just has a better sound and I had a box that was built to spec, sounded great, was curious and added fill and it came alive. My 10 sounded like a 12 and bumped so hard, like night and day. I didn't even add much either, maybe 1 inch pieces all around (ported). The sound waves are going hard inside a sub box, and they shouldn't be, its the other side of the sub obviously where sound waves should be going ham. Hasn't anyone ever noticed most home audio subs always have some sort of fill inside? Even if it's manufactured to perfect spec? It's for better quality bass and it just works. Link to comment Share on other sites More sharing options...
Bayuk89 Posted January 6, 2016 Report Share Posted January 6, 2016 Hi all, So recently I decided to go for a subwoofer and purchased an Infinity Reference 1262w (300w rms) and decided to build the box myself with limited woodwork skills. Being relatively new to the audio scene, Is 22mm (approx 7/8") plywood good enough, Is it necessary to double baffle the front side of the box? also, should I add polyfill to the enclosure? Note: Box is sealedThanks! Have you considered using 3/4 MDF wood instead of plywood ? Mdf is smoother and might sound better than plywood, i never used plywood before so i have no idea how it sounds. i had two infinity 1052w subs and another time i had a infinity 1252w sub and i liked them both. Go on the google play store and download "ultimate car audio app" it has a box maker calculater on it u have to put in length height and depth and it will tell u ur measurements to cut and tell you what ur net volume is Link to comment Share on other sites More sharing options...
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