[murf]

Hello Audio Experts!
  I have some big 3-way speakers that I want to tweak further.  My latest idea is to put some absorber/difuser on the back of the woofer & mid magnets to diminish the effect of the returning sound waves.   
1) Good idea?
2) What is best?
  I think something like Whispermat WM2 might be best.  It has 1/4" of foam (magnet side?), a barrier layer, then 1" of foam (enclosure side?).  The wave would be lessened by the 1", then hit the barrier, which would be decoupled from the magnet by the 1/4" foam.  I figure this to be better than a Deflex panel which is my second choice, or No-Rez which would put the barrier layer right on the magnet.  Third choice, modeling clay!
All suggestions welcome!

TIA,  Murf   

[Letitroll98]

The only product designed for this application is the Deflex Magnapads.  They are certainly cheap enough and come in any size you could need.  http://www.partsconnexion.com/damping_specdyn.html

[chrisby]

also when enclosure depth is sufficient, some folks use conical, bullet shaped or even stepped stacked discs* on magnet to further deflect the reflected waves


* cutouts from couple of sizes of hole saws works great for this

[murf]

Hi Chris,
What would these discs be made of, pls?

Murf

[tomagardner]

How about placing them on the back of the cabinet behind the speaker?

[Letitroll98]

How about placing them on the back of the cabinet behind the speaker?

I haven't used them myself, but from what I gather they are specifically used to shield the driver from the backwave, not deaden the cabinet so much that there is no reflections.  i.e Instead of damping the cabinet to the point of lifelessness, you bring a little clarity to the driver in question.

[chrisby]

Hi Chris,
What would these discs be made of, pls?

Murf

sorry for the delayed reply -

I've seen several different types of material used - depending on location.

including hand carved rigid styro-foam on back of magnets, stacked rings / hole saw cutouts on rear panel behind drivers (scraps of whatever construction  material is at hand)  , and then of course the (now discontinued?) Fostex reflectors

keep in mind that some of these devices might consume enough space to require adjustment of enclosure volume