Bottlehead Forum

General Category => Technical topics => Topic started by: Jamier on May 27, 2019, 08:24:29 AM

Title: Closed Cell Foam Ring?
Post by: Jamier on May 27, 2019, 08:24:29 AM

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

Title: Re: Closed Cell Foam Ring?
Post by: Paul Birkeland on May 27, 2019, 10:16:49 AM

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

Title: Re: Closed Cell Foam Ring?
Post by: Jamier on May 27, 2019, 02:35:15 PM

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

Title: Re: Closed Cell Foam Ring?
Post by: Doc B. on May 27, 2019, 06:08:38 PM

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

Title: Re: Closed Cell Foam Ring?
Post by: Paul Birkeland on May 27, 2019, 06:52:13 PM

Quote from: Jamier on May 27, 2019, 02:35:15 PM

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.