poly fill, why then dynamat

westmassguy

leftwinger57 wrote: »

Z3rOs, your last paragraph where your assessing BH-5 is really spot on. Like I already said the stuff works as advertised and one should know what to expect and the amount or size of the panels. I don't even think M5s or Jrs. are worthy of the stuff because of their size. When I did my 2Bs at the right height, length, and spacing and did not enter the passive cavity, it was still so dramatically different I really wasn't sure if it was the thing to do. If used incorrectly or in abundance you will kill the performance of those speakers. I think I might have asked this ages ago but if you have a speaker w/o the poly- fill that's supposed to be there would Corning Pink house insulation work in it's place ?

You can Lew, but why would you want to? Bonded Dacron Batting is available just about everywhere. I picked up some for a CRS+ Project I'm doing with Darryl.

leftwinger57

Thanks Dave, I live near a new construction housing site and the stuff is readily available. You know me, if I can get stuff that works for free then I'll do that. If it's the wrong application I would take your advice and go w/ the batting. In both my Polks the poly fill appears to be full original rolls and kept lily white clean.

drumminman

ZLTFUL wrote: »

drumminman wrote: »

One more time and I'm done: "Product: A 5 layer high efficiency acoustical absorption pad with a pressure sensitive adhesive back. Use: to provide the best complete acoustic damping for speaker and subwoofer enclosures."

It absorbs sound waves, not air, in order to prevent them from bouncing around inside the cabinet and hitting the back of the MW's. It may have a secondary function of dampening speaker wall vibrations, but it's primary purpose is absorption.

I think you're confused. That's exactly what I said.
Polyfill isn't there to dampen anything. It is there to help disperse air molecules which then makes the enclosure appear larger to the drivers.

BH5 is absorption and dampening/damping.

2 different materials doing 2 completely different things.
Your original post said they were doing the same thing but they are most assuredly are not. One is damping/absorption (BH5) the other is dispersion (Polyfill).

But your above quote contradicts what you said here:

drumminman wrote: »

BH also makes the cabinet appear larger to the drivers. It's not really for deadening.

Which is the part that I have said and will continue to say is incorrect.
The quote at the top is spot on. This isn't meant as an insult but when you compare the 2, you flip-flopped from what you originally said to now.

Now, we are on the same page.

I haven't changed what I said at all, just said it in a different way. By absorbing the energy from the back wave and not allowing it to bounce back and hit the MW's, the cabinet appears "larger" to them. It's a similar effect to the cabinet sides and back being so far away from the MW's that the back wave loses energy before it can reach a surface to bounce off.

ZLTFUL

O...k...

On3s&Z3r0s

westmassguy wrote: »

leftwinger57 wrote: »

Z3rOs, your last paragraph where your assessing BH-5 is really spot on. Like I already said the stuff works as advertised and one should know what to expect and the amount or size of the panels. I don't even think M5s or Jrs. are worthy of the stuff because of their size. When I did my 2Bs at the right height, length, and spacing and did not enter the passive cavity, it was still so dramatically different I really wasn't sure if it was the thing to do. If used incorrectly or in abundance you will kill the performance of those speakers. I think I might have asked this ages ago but if you have a speaker w/o the poly- fill that's supposed to be there would Corning Pink house insulation work in it's place ?

You can Lew, but why would you want to? Bonded Dacron Batting is available just about everywhere. I picked up some for a CRS+ Project I'm doing with Darryl.

The batting I've been able to find has always looked way thinner (at least in its retail packaging) than the stuff that has come in the speakers. Even the "ultra high loft" quilting stuff. Does it fluff up after you take it out of the bag? The last time I added some beyond stock I stole some loose polyfill my wife uses to stuff things like throw pillows. I just put it behind the tweeter and stapled the stock batting under it so I didn't have to worry too much about the loose stuff falling down.

Maybe I should tell my wife to get into quilting so I can try the batting.

With all the kitchen and needlework content this thread is turning downright Martha Stewart.

westmassguy

This is what I bought: http://www.ebay.com/itm/310173880013?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT