Personal computing discussed
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nerdrage wrote:I used R-11 fiberglass insulation inside the speakers and subwoofer I built and it makes a major difference in the sound quality.
Deanjo wrote:You should NOT use fibreglass insulation for filler. What happens is the glass particulates often find their way into the spider and voice coil causing rubbing and wear.
Chrispy_ wrote:I've done what Ludi has said to do - a foam anechoic surface.
I did it using plain old sofa foam and cutting a block in half with a sawtooth pattern, made a pretty big difference to the resonant boomy/muddiness of the speakers.
nerdrage wrote:Deanjo wrote:You should NOT use fibreglass insulation for filler. What happens is the glass particulates often find their way into the spider and voice coil causing rubbing and wear.
I've been using three speakers with fiberglass in them since 1996, without issue. It was the recommended filler material according to the Loudspeaker Design Cookbook.
Regardless, polyfill is admittedly easier to work with and cheaper.
Deanjo wrote:nerdrage wrote:Deanjo wrote:You should NOT use fibreglass insulation for filler. What happens is the glass particulates often find their way into the spider and voice coil causing rubbing and wear.
I've been using three speakers with fiberglass in them since 1996, without issue. It was the recommended filler material according to the Loudspeaker Design Cookbook.
Regardless, polyfill is admittedly easier to work with and cheaper.
Oh I know the LDC all to well. It also has a bunch of outdated information and was written before most speakers had a vented coil. Also using fibreglass insulation is a large health hazard when used in a vented enclosure. There is a reason why masks are required when handling the stuff.
ludi wrote:There are two modifications that would improve the sound -- the fiberglass or polyfill approach will help with the bass range, since it works by reducing the standing waves that form within the cabinet.
For the upper-bass and midrage frequencies, you need acoustic foam with the usual "eggcrate" anechoic surface. The favorite supplier for all things DIY audio is Parts Express, and a suitable block of foam is available here. One sheet per cabinet should do the trick. Cut sections and glue them to the interior walls. The front baffle can be omitted.
The result of completing these mods should be a speaker that sounds noticeably tighter and more defined across the audio spectrum, but which will also seem to lose some of its former bass response. Once you adjust to the change in the sound, and/or adjust your tone controls to compensate, they should be significantly improved.
However, there are two potential problems that won't be solved:
1) Woofer surrounds -- A quick GIS suggests these units use foam. Are they getting dry, or already starting to crack and break up? If so, rapid deterioration will follow.
2) Crossover -- most cheaper commercial speakers use very cheap crossover designs and have electrolytic capacitors that dry out with age.
There are repairs that can be done, but if it looks like you're going to be spending at least $50 to resurrect an old and relatively low-quality speaker system, you might want to look into the Overnight Sensations that alloyD linked. The complete kit, assuming you can do some basic soldering, is $120. They will completely blow away the Yamaha set, and you have the luxury of choosing how to finish the cabinet.
PenGun wrote:I built fish boats for a while, fiberglass ones. You cannot inhale normal fiberglass, it's long fibers just hang up in your nose and respiratory system. Now fiberglass that has been powdered and grindings from set up fiberglass parts can be a real problem.
The Swamp wrote:I checked the speakers, hoping the back has screws that would allow me to remove the back panel. There's none, so it looks like accessing the interior of the speakers is going to be a bit of a pain. I guess I am supposed to go in through the woofer opening. The crossovers are just caps. I'm guessing I need to replace those?
Deanjo wrote:PenGun wrote:I built fish boats for a while, fiberglass ones. You cannot inhale normal fiberglass, it's long fibers just hang up in your nose and respiratory system. Now fiberglass that has been powdered and grindings from set up fiberglass parts can be a real problem.
Helped run a fibreglass factory myself with my brother inlaw (building/designing boats, water/septic tanks, van camper tops, etc). As you should know by building fibreglass boats that fibreglass comes in many forms (not only in fibre spools which is then fed into the chop gun where it is mixed with the catalyst and resin and chopped up into smaller strands and millions of microscopic glass particles in the process). Fibreglass insulation itself contains many many many small glass particles.
Just google shuttlecraft if you want to see the boats we built (they docked with pwc's).
https://www.google.ca/search?q=shuttlec ... f&tbm=isch
http://www.nachi.org/fiberglass-insulat ... atives.htm
PenGun wrote:A chopper gun. Oh my, low grade. We did all hand layup on our stuff.
The Swamp wrote:I did that with a pair of speakers given to me by a friend. Both woofers were blown, so I ordered some appropriate ones from Parts Express and screwed 'em in. They sounded just fine. More tinkering wasn't worth the time per improvement ratio. I think the total cost was under $100.I put the speaker back together and tried it out. It does seem to sound a bit richer and fuller, but it was hard to tell from just the TV signal. I've been thinking of getting a pair of woofers from Parts Express. I think even cheap ones would be an improvement over the ones in there now. I'd like to use them for surrounds, maybe.
The Swamp wrote:I was able to get a huge sheet of foam carpet padding from a local flooring store. I opened up one of the Yamaha speakers by removing the woofer. There's not much to the woofer. It was much lighter than I expected, with a fairly small magnet. I unplugged it and looked inside the cabinet. Sure enough, it was completely empty. Shouting into it created a loud pronounced echo/reverb. I was thinking that cannot be very good. I cut a fitted sheet of padding and glued it to the back wall, then rolled up two sheets (top to bottom length) and put them into the enclosure. The echo/reverb was gone after that.
The Swamp wrote:I knew the padding was not the best material, but that can be offset by using more of it. The echo in the cabinet was pretty sharp since it's a fairly deep cabinet. I was surprised about how light the woofer was. There's just not much to it at all. I'm guessing the other components are also not of...ahem... great quality as well?
The Swamp wrote:The caps for the specific drivers seem to be 4.7uf for the midrange speaker and 1.5uf for the tweeter. The woofer does not have a cap. Should it have one?