Closed Cell Foam Ring?

[Jamier]

I have some Eminence woofers that will be in a speaker that I’m building. They have a closed cell foam ring on the outer face of the frame. I have never worked with a “Pro” driver before and I was wondering why these are there. Is it to reduce diffraction since the frame is stamped and has lip on the outer edge or is it just for the physical protection of the woofer frame?

Jamie

 

[Paul Birkeland]

Often times this is a hold over from when it was extremely common to rear mount drivers inside a cabinet.

 

[Jamier]

PB, thanks for the reply. For best result, should the driver be flush mounted to the level of the foam ring or to the level of the stamped frame, leaving the foam ring proud with respect to the baffle surface?

Jamie

 

[Doc B]

Unless the woofer goes high like a tweeter that foam ring will be inconsequential at the frequencies it emits.

 

[Paul Birkeland]

PB, thanks for the reply. For best result, should the driver be flush mounted to the level of the foam ring or to the level of the stamped frame, leaving the foam ring proud with respect to the baffle surface?

When I have seen these recessed, it has been to the level of the foam ring.