Yes, contributes to the death of all the sounds that might be inside the box. But with board (and other materials for that matter), don't line the walls but just toss sheets into the middle space.
Some disputes about what is the right amount, esp re sealed boxes. And cross-bar bracing is likely the priority (old broomsticks* held by epoxy is simple). But enhancing deadness and removing ringing by any means is good for a music reproducer.
B.
*of course in Canada, we always use broken maple hockey sticks available by the dozen at your local rink
Some disputes about what is the right amount, esp re sealed boxes. And cross-bar bracing is likely the priority (old broomsticks* held by epoxy is simple). But enhancing deadness and removing ringing by any means is good for a music reproducer.
B.
*of course in Canada, we always use broken maple hockey sticks available by the dozen at your local rink
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I believe there can be substantial air pressure in a small sub, i'm sure some polyester fill can make the sub box perform better
http://bgavinsound.com/Reference/Sp... Sealed Cabinets/adiabatic vs. isothermal.txt
http://bgavinsound.com/Reference/Sp... Sealed Cabinets/adiabatic vs. isothermal.txt
1/ damping in a reflex box like you are building should only be used to reduce standing waves
and
2/ as Ben says at the frequencies a sub outputs, you will not generate any signal at the frequencies the damping will affect — alou you might find spurious noises that are.
… so damping serves little to no benefit.
dave
and
2/ as Ben says at the frequencies a sub outputs, you will not generate any signal at the frequencies the damping will affect — alou you might find spurious noises that are.
… so damping serves little to no benefit.
dave
As said, damping material at Sub frequencies is of little benefit and can effectively increase the acoustic size of the cabinet which may adversely affect the overall response of the Sub. Bass output may lack some 'punch' with the damping but by all means give it a try, outcomes are not always predictable.
C.M
C.M
Yes, always a great source of data. But the interpretation needs some attention.
1. Fill damps and enlarges the box. This can throw off the BR or PR tuning unless anticipated in the design.
2. The internal echoes north of the crossover point do matter because drivers make distortion and this is relatively more audible due to Fletcher-Munson than the fundamental and these upper resonances can get stimulated and need to be damped.
3. What the link calls loss of "efficiency" is really loss of crap. The fill has improved the transient behaviour of the boxes and pared away false sound. Sure sounds like a trade-off I'd want to take to get better quality sound.
B.
A tight box may ring like a bell. Not only because of it's own drivers, but because others in the room are exciting it. Much like central heating radiators and random item's of furniture often become sounders, even though they have no drivers of their own. I note your just building one sub, but often people build two, then sit mid/top boxes upon them. Perhaps yours will form a TV stand with center speaker upon it?
I don't think it would hurt to chuck a pillow or two in there. I lined mine with rubber crumb carpet underlay, knowing mid/top boxes were part of the design. It does indeed lower the output. By removing noise that shouldn't be there. Which for hifi is right, but for PA systems where the punch is paramount, damping out the echo is hard to justify.
I don't think it would hurt to chuck a pillow or two in there. I lined mine with rubber crumb carpet underlay, knowing mid/top boxes were part of the design. It does indeed lower the output. By removing noise that shouldn't be there. Which for hifi is right, but for PA systems where the punch is paramount, damping out the echo is hard to justify.
Thanks again Ben,
How’s the weather in Delray ?
Unfortunately fall is definitely upon us in the Chicago area.
Friendly1uk - I’m just starting to assembly a home theater system. I do plan on another subwoofer. I still need to build the left and right channel speakers. I already have the components (Apollo MTM by Pete Schumacher). Designing the cabinets at work to take advantage of the CAD system. Other components still up in the air. I have come to realize that I may need to add 1 or 2 dedicated 15 amp circuits for the amplifiers.
Thanks
How’s the weather in Delray ?
Unfortunately fall is definitely upon us in the Chicago area.
Friendly1uk - I’m just starting to assembly a home theater system. I do plan on another subwoofer. I still need to build the left and right channel speakers. I already have the components (Apollo MTM by Pete Schumacher). Designing the cabinets at work to take advantage of the CAD system. Other components still up in the air. I have come to realize that I may need to add 1 or 2 dedicated 15 amp circuits for the amplifiers.
Thanks
This was my experience exactly, when testing both a sealed sub (3 cubic ft, single 18") and several ported designs.
My preconception was that the guys saying "no fill is better" were crazy, but my results proved them right. In all three cases, the subs lost punch and fullness with the fill, and IMO this was not a case of them simply getting tighter. They just plain sounded worse. (and I expected them to sound better, so no psychological effect going on with this test.)
YMMV.
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