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Aric
Aric, Engineer
Category: Home Theater-Stereo
Satisfied Customers: 43056
Experience:  15+ years in the field. Owner of AV Installation, OEM and Repair company
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LOUDSPEAKER CONSTRUCTION: I am rebuilding an old bookshelf

Customer Question

LOUDSPEAKER CONSTRUCTION: I am rebuilding an old bookshelf Cerwin Vega 12" set of speakers. I MUST replace the Kapok or loosefill in it. Is standard pink house insulation an adequate substitute for whatever the factory uses? I am not a sound purist. I just want lots of BASS. The ideal / correct amount of base for me is "TOO MUCH BASS" if you get my drift. I love pipe organ music and hard rock. $25.00 a pound seems WAY overpriced for the material specifically labeled for loudspeaker use. Note: the particular I am rebuilding is a ported enclosure. It is a Cerwin Vega 12" model 1230 HED cabinet with a L121-4 12" woofer. SECOND part of question. This system uses an old fashioned red button mechanical resettable breaker. Wouldn't it be far better to replace that relatively slow acting with either a slo-blo standard fuse or perhaps even a standard fuse of approximately the same amperage?
Submitted: 1 year ago.
Category: Home Theater-Stereo
Expert:  Aric replied 1 year ago.

Hello, I've been building loudspeakers for the better part of 20 years and can help. Do not use fiberglass insulation, it will blow fibers through the port and can also stick to the back of the woofer cone as it is not stagnant and the fibers will blow around inside of the cabinet. Use the inexpensive "egg-crate" foam they sell at Wal-Mart and line the back, sides, top and bottom of the cabinet with it using hot glue. Do not line the back of the baffle that the woofer mounts to.

Regarding the breaker- lose it. The CV breakers always trip prematurely, and they are designed to trip when the first instance of DC is sensed at your amplifier output. I would lose the breaker altogether and simply make sure you don't clip your amp. If you wanted to use a fuse a slo-blo will work of the same amperage rating.

If you need further assistance let me know. Please do not forget to click the 5 STAR RATING, at the top of the page for my efforts. It is my livelihood and you can follow up at any time if needed.

Customer: replied 1 year ago.

Please expand on your description of the Walmart product you are speaking about. Can you go to their website and locate it then give me their sku number so I get the right thing? Ideally I should put it on all 4 sides and just not the rear wall? Or, as I have seen some just top and one side? Obviously cost is not important if I;m buying it from wally world so please tell me what you consider ideal coverage. And, how thick? 2 to 3 inches or so? Oh, if you need some FREE precision resistors and similar let me know. I;m donating kits to ppl that are interested in component level construction. 5 stars upon your reply of course. Len

Expert:  Aric replied 1 year ago.

Thanks for the reply Len. The 1.25-3" thick material, on the back, sides top and bottom wall of the enclosure work best for ported boxes. I've always used the 1.25" material for 6-10" woofers, and 3" for 12" up to 18". It's sold as "egg-crate" foam- or "convoluted mattress foam" (at the link below):

1.25"

http://www.walmart.com/ip/Mainstays-1.25-Convoluted-Foam-Topper-Twin/10055840

3"

http://www.walmart.com/ip/Simmons-Beautyrest-BigSleep-3-Convoluted-Foam-Topper/34961198

I wish I could take you up on the resistors, but site rules state I cannot contact you outside of the site unfortunately. Thank you for the offer though- it's much appreciated.

If you need further assistance let me know. Please do not forget to click the 5 STAR RATING, at the top of the page for my efforts. It is my livelihood and you can follow up at any time if needed.