Okay I'm getting a box and the mtx site says they should have 1.25qft of airspace for the sub. Now does this mean the chamber has to have 1.25qft AFTER the sub is inside, or just 1.25qft for putting the sub into?
thx
Replies (9)
lewis on 04/12/2006 22:39:15
usually thats the space thats needed besides what the speaker takes up (add the speaker dispacement usually listed in the specs)
lakecityransom on 04/12/2006 23:24:37
Okay, I have the T5512-04 shown here http://www.mtx.com/caraudio/products/subwoofers/thunder5500.cfm
That makes sense, but whats port displacement? Ported boxes only or something I need to factor in?
Another question, is going under or over the limit particularly harmful or just degrading of bass? Either way, how does going over affect the bass? I know under affects the deep bass ability.
With that info the closest thing I can get to 1.25+0.7 is this 1.30 box:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9710131925&fromMakeTrack=true
look good or would you recommend me get one thats perfect?
lewis on 04/12/2006 23:49:45
port displacement is for ported boxes only....usually the box size you just want as close as possible to the manufacturers specs. you can go a little over or under without any problems and you can fine tune with poly fill or similar materials (for boxes too small) or blocks of wood (for boxes too big). prefab boxes in most cases arent that great but they will work if you dont want to build your own. if you decided to go with that box it would work pretty good with your subs (thats about as close as i would expect to get on box size)
hope that helps
swez on 04/13/2006 11:13:02
Agreed! We really have a window of +/- 10% on sub enclosures.
The larger the box is over woofer specs, the more boominess we often get and some sloppy bass as well. I have found the older MTX subs to work best in slightly smaller enclosures than specified. If they say 1.25 cf sealed, I have noted better results in 1.1 cf, with some polyfill, will tighten up the bass and still get plenty good lows.
As noted by Lewis, if you get a larger box and it sounds boomy or sloppy, adding a few 2x4's of the proper length, will bring the box down in air space. Just remember, in "dimensional lumber", a 2" x 4" board is actually 1-1/2" x 3-1/2". Be sure to glue and screw these in as needed. (2" dry wall screws are perfect)
Swez
lakecityransom on 04/13/2006 11:21:41
I just started hearing about this polyfill stuff, where should you buy this stuff and how do you go about putting it in the box? How can you tell how much airspace increases? How much can it fix a box? Surely stuffing a small box full of poly fill doesnt work? I guess it slows down the waves but wont it sound different from the correct sized box?
Sorry Im a huge noob
lewis on 04/13/2006 18:45:13
never used the stuff myself but heres what i think i know about it...
polyfill is pretty much just a padding material (like you would find in some pillows). you can usually buy it at walmart or a fabric store. it will usually be in a roll and you can just unroll it and fold until you have the ammount you need then stuff it in the box through the speaker hole.
i would assume that it could make big differences because it would slow down the air movement inside the box (so it would be like a bigger box). ive seen people use just a little and ive also seen boxes that were stuffed completely full. the more you put the slower the air will move inside (to a point anyways). like i said though im pretty much going from how i think it would work.
i wouldnt expect a major change in sound when you compare a smaller box with (the right amount of) polyfill to the actual size box because you are essentially tricking the sub into thinking its in the bigger box.
hopefully im pretty close on this but im sure if i said something wrong there will be someone to correct me. im trying to learn as much as possible here too so if anyone has any corrections or additions please post them.
swez on 04/16/2006 17:11:09
Polyfill has a lot of air pockets and it does slow down the rear cone wave reflections in the box. However, it's not a cure all for a poorly matched box/woofer combo.
How much to use? For a single 12"sub, 12-16 ounces of loose fill is generally appropriate. If you find it in sheet goods form, (for quilts) look for enough to give about 1-1/2" thickness, cut pieces as needed to fit on back, top/bot and side panels. Then, staple it in so it does not float about in the box.
Swez
Ash on 04/16/2006 18:34:22
Fill is not normally applied the same in ported as it is in sealed. This is even debatable. Batten affixed to the walls is usually better in ported so it won't move around and enter the port. Loose fill is okay for sealed.
Like Swez states, it is better to shoot for a proper tuned enclosure for the results from fill is usually minimal and can cause for retuning.
lakecityransom on 04/17/2006 00:31:34
Okay thanks fellas I was just looking for a miracle cure. Obviously not possible as thought. Well thanks this place is the best.
thx
Replies (9)
lewis on 04/12/2006 22:39:15
usually thats the space thats needed besides what the speaker takes up (add the speaker dispacement usually listed in the specs)
lakecityransom on 04/12/2006 23:24:37
Okay, I have the T5512-04 shown here http://www.mtx.com/caraudio/products/subwoofers/thunder5500.cfm
That makes sense, but whats port displacement? Ported boxes only or something I need to factor in?
Another question, is going under or over the limit particularly harmful or just degrading of bass? Either way, how does going over affect the bass? I know under affects the deep bass ability.
With that info the closest thing I can get to 1.25+0.7 is this 1.30 box:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9710131925&fromMakeTrack=true
look good or would you recommend me get one thats perfect?
lewis on 04/12/2006 23:49:45
port displacement is for ported boxes only....usually the box size you just want as close as possible to the manufacturers specs. you can go a little over or under without any problems and you can fine tune with poly fill or similar materials (for boxes too small) or blocks of wood (for boxes too big). prefab boxes in most cases arent that great but they will work if you dont want to build your own. if you decided to go with that box it would work pretty good with your subs (thats about as close as i would expect to get on box size)
hope that helps
swez on 04/13/2006 11:13:02
Agreed! We really have a window of +/- 10% on sub enclosures.
The larger the box is over woofer specs, the more boominess we often get and some sloppy bass as well. I have found the older MTX subs to work best in slightly smaller enclosures than specified. If they say 1.25 cf sealed, I have noted better results in 1.1 cf, with some polyfill, will tighten up the bass and still get plenty good lows.
As noted by Lewis, if you get a larger box and it sounds boomy or sloppy, adding a few 2x4's of the proper length, will bring the box down in air space. Just remember, in "dimensional lumber", a 2" x 4" board is actually 1-1/2" x 3-1/2". Be sure to glue and screw these in as needed. (2" dry wall screws are perfect)
Swez
lakecityransom on 04/13/2006 11:21:41
I just started hearing about this polyfill stuff, where should you buy this stuff and how do you go about putting it in the box? How can you tell how much airspace increases? How much can it fix a box? Surely stuffing a small box full of poly fill doesnt work? I guess it slows down the waves but wont it sound different from the correct sized box?
Sorry Im a huge noob
lewis on 04/13/2006 18:45:13
never used the stuff myself but heres what i think i know about it...
polyfill is pretty much just a padding material (like you would find in some pillows). you can usually buy it at walmart or a fabric store. it will usually be in a roll and you can just unroll it and fold until you have the ammount you need then stuff it in the box through the speaker hole.
i would assume that it could make big differences because it would slow down the air movement inside the box (so it would be like a bigger box). ive seen people use just a little and ive also seen boxes that were stuffed completely full. the more you put the slower the air will move inside (to a point anyways). like i said though im pretty much going from how i think it would work.
i wouldnt expect a major change in sound when you compare a smaller box with (the right amount of) polyfill to the actual size box because you are essentially tricking the sub into thinking its in the bigger box.
hopefully im pretty close on this but im sure if i said something wrong there will be someone to correct me. im trying to learn as much as possible here too so if anyone has any corrections or additions please post them.
swez on 04/16/2006 17:11:09
Polyfill has a lot of air pockets and it does slow down the rear cone wave reflections in the box. However, it's not a cure all for a poorly matched box/woofer combo.
How much to use? For a single 12"sub, 12-16 ounces of loose fill is generally appropriate. If you find it in sheet goods form, (for quilts) look for enough to give about 1-1/2" thickness, cut pieces as needed to fit on back, top/bot and side panels. Then, staple it in so it does not float about in the box.
Swez
Ash on 04/16/2006 18:34:22
Fill is not normally applied the same in ported as it is in sealed. This is even debatable. Batten affixed to the walls is usually better in ported so it won't move around and enter the port. Loose fill is okay for sealed.
Like Swez states, it is better to shoot for a proper tuned enclosure for the results from fill is usually minimal and can cause for retuning.
lakecityransom on 04/17/2006 00:31:34
Okay thanks fellas I was just looking for a miracle cure. Obviously not possible as thought. Well thanks this place is the best.
Copyright ClubKnowledge 2009 * All Rights Reserved
