Using reticulated foam with waveguide loaded soft dome tweeters

[Westy37]

I've recently loaded some seas 27tdfc soft domes in MCM6.5" waveguides ala Zaph audio:

Zaph|Audio

I'm just curious whether anyone has experimented using reticulated foam in such shallow waveguides? Would there be any advantage? I've seen it done in deeper waveguides and compression driver based set ups but not with soft domes.

For those unfamiliar with this idea of using foam in waveguides see this site:
Red Spade Audio: Waveguide foam mod

[sreten]

Hi, I can't see any issues it would address for that combination, rgds, sreten.

[norman bates]

I agree with sreten. I wouldn't bother with foam in the throat on that horn (it's lovely). If anything, wrap the edges of the horn with thicker foam (or felt) to prevent some highs from hitting the baffle edges.

check out post 3, long read but worth it for a free improvement. Granted, the conical has a steep edge, while the mcm goes smooth into the baffle. Foam around the edge works for my ev hr90, klipsch rb 75, and mcm 6.5" round horn.

Geddes on Waveguides

Conical Horn Dip

Norman

[dirkwright]

Originally Posted by Westy37

I'm just curious whether anyone has experimented using reticulated foam in such shallow waveguides? Would there be any advantage? I've seen it done in deeper waveguides and compression driver based set ups but not with soft domes.

For those unfamiliar with this idea of using foam in waveguides see this site:
Red Spade Audio: Waveguide foam mod

Just so you know, Dr. Geddes has patented this idea of using reticulated foam in waveguides... You have to ask his permission to make, use, or sell anything with this feature in the U.S. I don't know if he has any international patents on it though...

[Ile]

Originally Posted by dirkwright

Just so you know, Dr. Geddes has patented this idea of using reticulated foam in waveguides... You have to ask his permission to make, use, or sell anything with this feature in the U.S. I don't know if he has any international patents on it though...

Patent doesn't mean nothing if he makes those for his own use, patents only try to protect agains commersial copying.

[jcx]

Originally Posted by Ile

Patent doesn't mean nothing if he makes those for his own use, patents only try to protect agains commersial copying.

not true in the US

practically there's little chance of being caught but US patents prevent "...make, use, sell"

there can be argument over "investigational use" - but bragging on the web about daily "use" in your home theater system could in principle get you a lawsuit

[dirkwright]

Originally Posted by jcx

not true in the US

practically there's little chance of being caught but US patents prevent "...make, use, sell"

there can be argument over "investigational use" - but bragging on the web about daily "use" in your home theater system could in principle get you a lawsuit

That is correct. The patent enables the owner to prevent anyone from making, using or selling their invention. It's called an infringement suit. So, if you want to do this and talk about it openly, I would suggest getting permission from Dr. Geddes first, in addition to reading his patent. At the very least, it is the polite thing to do. He worked hard on that invention and another person's making, using or selling it amounts to stealing of intellectual property.

[badman]

Just for completeness sake- his patent I believe only covers >80% fill rates, a small amount just in the throat pre-dates his use.

[Westy37]

Thanks for the informative replies. Have some SAE-11 felt on the way to experiment with baffle diffraction so may end up using some around the transition from the waveguide to the baffle.

[norman bates]

you will notice a sharpness. You can really hear what a recording studio does to a woman's voice (reverb, sustain, etc). We look forward to your results (don't forget the pics).

Norman