Horn Honk and Towels

[Sheldon]

The key is what PPI (Pores per inch) are you guys using and do you re-EQ the devices after the foam insertion?

I do have a bulk of foam that I am not going to be able (no more Summas) to use and I would be glad to sell, but the stuff is very expensive, even when buy in bulk.

I don't know the pore size, but I got it from the good Dr. himself (and since he let the cat out of the bag, I guess there is no reason to be coy), so I guess it's the good stuff.

By the way. Dr. Geddes sent me two cubes dimensioned to the size of the mouth. If you are willing to do some cutting and carving, you can get away with quite a bit less than that. You'd dimensions big enough to have one continuous piece for the mouth, just for appearances sake. But I don't see any reason that the inside can't be put together from smaller pieces. As the foam is quite pliable, absolute perfect matching of the cuts shouldn't be necessary.

Sheldon

 

[gedlee]

Hello,

I'd like to try some if it's not too much trouble or $$. I need enough for a 2" throat 300 Hz round tractrix horn. It's about 14" in diameter

Please email: mochamike@neo.rr.com

The pieces that I have are cut at 12", so that is the largest dimension. A 12" X 12" x 8" block is $25.

I can't sell anything until I return in September.

 

[gedlee]

No more Summas?! This is unfortunate, and news to me.

I am going to stop making them by hand because we are making them in quantities in Thailand. They will be available from Ai as the ESP line. It might be a while before we get them imported into the US through dealers, but they are always availbale from Thailand. The ones made there are actually a lot better.

I have two sets left here that were hand made - the last of their kind if anyone is interested.

 

[dwk123]

At the risk of exposing myself as having made a colossal blunder, I used this stuff (scroll down to the 'speaker foam' entry at the bottom of the page)

http://www.foambymail.com/Hi-FlowFoam.html

30 ppi reticulated open cell polyurethane foam. This may not be the exact stuff that Earl used in the Summa, but it sure looks like what I remember seeing at RMAF. The downside of this source is having to cut and stack slices to build up a larger plug. I got the largest piece (2"x6'x4') and used about half of it for my U15s. Not exactly cheap, but much cheaper than McMaster, and a screaming bargain considering the result.

 

[Patrick Bateman]

To me the problem with the Unity is exactly that the sound is injected radially which will tend to set up strong Higher Order Modes (HOM). To me the idea is to reduce the HOM and the mouth reflections as much as possible through design. The unity horn does not fit this criteria.

You and Sheldon may be interested in one of my new waveguides. It's an OS curve with one exception. The compression driver isn't mounted axially, it's mounted a bit closer to the wall of the waveguide.

Picture a cross between the Unity with the mids on the horn sides, and an OS waveguide with the compression driver at the throat, and you'll get the general idea.

I needed a waveguide which fit in a very confined space, and it was good to see that this unorthodox mounting method appears to work.

I'll post measurements and pictures in the next few days.

 

[Soldermizer]

In honor of the 12th anniversary of this thread, may I suggest the towel trick be named, in honor of the Hitch-Hiker's Guide reference, to be "The Ravenous Bugblatter Beast of Traal Towel Mod"?

 

[jo-briggs]

Surely the correct number of pores per inch is 42...

 

[AllenB]

Sorry, what was the question?

 

[wolf_teeth]

'If I told you, you wouldn't like it.'

Wolf

 

[Bigun]

In honor of the 12th anniversary of this thread, may I suggest the towel trick be named, in honor of the Hitch-Hiker's Guide reference, to be "The Ravenous Bugblatter Beast of Traal Towel Mod"?

I’d support that.