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Advent Speaker Stuffing Options

guptonr

guptonr

Active Member
I've recently acquired a pair of original Advent Loudspeakers (utility cabs/masonite ring woofer) that I'm going to recap, refoam, and cover with veneer. During disassembly, I realized I had two different versions. The cap difference in the crossover will be taken care of with the recap. One speaker had foam pads as stuffing and the other had pink fiberglass. I read on this sight that the pink fiberglass is preferred.

I happen to have several sheets of 48x24x2 Owens Corning 703 and 705. Does anyone have any thoughts on using this instead of pink insulation? The 703 and 705 are much better at sound absorption than the standard fiberglass insulation. Would this improve or degrade the speakers' output. I'm reluctant to cut up a couple of panels just for experimenting.
 
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I don't see a problem with the 703 or the 705. You could always use fiberfill that you can pick up at Walmart.
 
I'd recommend that you utilize the original damping material that Advent so diligently applied to tune the low frequencies.
 
I advise against using the panels for an acustic suspension application. They might work well in a vented cabinet to dampen the back wave, but the purpose of the loose FG in an AS cabinet is different. The mass of fibers slows down the speed of sound and changes the energy into low level heat thus making the cabinet seem larger than it really is.

Weigh the amount of loose FG you pulled from one of the speakers and match that weight with some comparable loose stuff you can purchase from Home Depot or other haome supply stores in the other cabinet that had the foam.

As a rule of thumb, I usually stuff at a rate of 1 lb. OC pink FG per cubic foot of internal volume.
 
Thanks for the advice. AK has always been quick to enlighten me. I'll go with what Kloss intended and use the pink fiberglass for both.
 
To my knowledge Original Large Advents never had those foam blocks but they were frequently used in the New Large Advents. I could be wrong. Anyway I would use the fiberglass.
 
archie2 said:
To my knowledge Original Large Advents never had those foam blocks but they were frequently used in the New Large Advents. I could be wrong. Anyway I would use the fiberglass.
Click to expand...

I found an excellent site on the web, http://baselaudiolab.com/ADVENT_LA_XO.html that described three versions of the original Advent Loudspeaker and had some reverse engineered schematics. I found another reference, can't find the site, that said the original version had foam blocks and revision one and two, along with the cap and resistor value differences, had been stuffed with fiberglass. Externally, each is identical. Mine appear to be a Revision 0, 1st version, and Revision 2 (third version). My go.al is to get them to match.
 
The Advent Loudspeaker originally had fiberglass in the cabinets, not foam.

They switched to foam around 1975.

I have some of each and they sound the same.

People just like to pick on the foam.

Doug
 
I have read that before.

I'm just saying that the audibility is apparently debatable.

I mean, the Fc difference is less than 2 dB and that is after bracing the cabinet with the FG version.

My different versions sound the same.

Doug
 
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