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How much Poly-fil should be needed in these speaker cabinets?

Mr Creosote

Mr Creosote

Super Member
I have been working on restoring a set of ESS AMT 1s. I'm ready to assemble everything back into the cabinets. when I took them apart the Poly-fil filled barely half the cabinet. It was matted down, mice had been in there. Should I fill it to about mid point, about to the bottom of the woofers? Fill the whole cabinet? Any suggestions for material other than Poly-fil? TIA...

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Beautiful enclosed refurbishment! They look absolutely nothing like mouse habitats! Make sure and share the final results! Looks like you’ve got a new HUGE Dayton poly cap in there. What’s the uf rating on that bad boy!?!
 
turnitup said:
Beautiful enclosed refurbishment! They look absolutely nothing like mouse habitats! Make sure and share the final results! Looks like you’ve got a new HUGE Dayton poly cap in there. What’s the uf rating on that bad boy!?!
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Thanks, I have another thread following my work

ESS AMT 1 Restoration project. Xover Capacitor suggestions.

I have a set of early 1st generation ESS AMT1 speakers. My brother bought them new sometime 1970-71. They been stored in his garage for about 30 years. well, cleaning out his garage I dragged them home. Sitting in a garage that long was not kind to them to say the least. Mice got into them and...
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I would put a piece of cloth over the crossovers, then fill them all the way up- try to not jam the fill in (too tightly packed) and not too loose either. My ancient Infinity RS4b speakers (big empty box) were stuffed full.
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painttoad said:
i would look at online pics of the cabinets with no woofers. they do not appear stuffed but they appear to be lined. ported speakers should not be stuffed full ime.
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Ooops didn't realize they were ported until now that I see the tube coming up from the bottom... then they should be about 1/2 full.
 
I wouldn't guess, or take generic advice. It should be possible to find the weight used in the original fill. If you can't find a reliable number online, weigh the original if you still have it. Speakers are designed and optimized for a specific amount of fill.
 
Thanks guys. The cabinets are about 1.5 cubic feet. I can't weigh the original because mice had nested in it, it got pulled out with a mask and gloves straight into a trash bag. They where about half full. I picked up 3 pounds today, looks like more than enough. I'll fluff it a little and fill to close to the bottom of the woofer. Eye balling the bags looks like a pound will be enough for a cabinet. I have an extra pound if not. I'll see if I can find the original specs, but being 50+ years old, wish me luck.
 
Thanks painttoad! What is that stuff? When I opened these up they had fiber-fil in them, It was the first time they had been opened. My AMT 1s are a very early model. I can't make out any date codes, but they where purchased in 1971 or 2. I thought about the fill being blown out the port. covering the port with a screen crossed my mind.
 
Mr Creosote said:
This is a tad less than a pound


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You need to get some on the sides and top, like a blanket. Most new speakers use thick foam on the sides, top, and bottom because it is easier to get it to stay in place with a dab of glue on the back side - you may want to try that instead (??) or maybe some sound absorbent pads like these:

 
@painttoad :thumbsup:

You have to leave the port clear to move the interior air. I assume there is a tube on it? If so just make sure the inner end of the tube is above any lining.

If you can find 2" Fiberglass insulation, that is what I've seen for most ported and even sealed speakers of that vintage, attached using just a few staples. to all four sides, top, and bottom.
 
Cotton batting, quilt lining. It's what was used originally in many speakers.

Can be bought very cheap at Joanne's fabrics right now on closeout.
 
I get my insulin via mail order and it comes in insulated packages filled with 1.5" thick sheets of this insulation/sound absorbent material made from cloth remnants. I've been saving it up over time and finally had enough to line the inside of my old Infinity RS4b speakers, which are big empty boxes stuffed with fiber fill. I lined them with this stuff then repacked the fiber fill... drums & bass guitar are nicely improved! I'll have them out in the main living room stereo for awhile: these speakers have a wide on axis sound, so the "sweet spot" is pretty wide. I've ordered some new diaphragms for the EMIT tweeters from American Vintage Audio - the glue holding the membranes down is now 40 years old and not holding any longer, so they are getting a little buzzy with high pitched voices when turned up to moderate levels.

My Monitor Audio Silver 500's are in the office and are sounding spectacular in there, as their on axis sound is pretty narrow but it works well in the smaller room since there is only one listening spot.
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