Rare and unusual wooden horn.

[Walloffound]

I just purchased this speaker. The back has a stamp saying "applied for patent" I could not find out much about what this is anywhere on the web. The driver said "Utah made In Salt Lake City" the wooden horn starts in the middle, looks like some early model PA speaker?
Anyone have some guesses about what this is? How do I test it without damaging it?

 

[kb2wyl]

Aren't University Speakers made there? Pretty sure, try looking that up 🙂

 

[Rev. Billy Bob]

Did it look like this?

1930's Utah Wooden Speaker Horn.

 

[Walloffound]

Yes that's the listing I picked up. What do you guys think ?

 

[kb2wyl]

Oh that's a compression driver, I was thinking more of a shallow horn with a full range. University made some excellent speakers, similar (some almost identical) to Altecs. I wouldn't be surprised if they made those as well. Google it, the company is still in business.

 

[Walloffound]

Can I use it as a tweeter?

 

[bwaslo]

That's an "offset horn", the same principle by which Danley Synergy or Unity speakers combine midrange into a horn that also has a tweeter at its apex. Offset horns can be modeled in HornResponse, if you want to get into software modeling and see how it behaves.

One of the characteristics of an offset horn is that the output from the offset driver will have a (very) sharp null at a frequency range that is 1/4 wave from the apex. I imagine the utility of that in the horn show above is to get rid of some nasty HF resonances from that driver or scratchy sounds from a phonograph driving it.

 

[Walloffound]

I am not able to post photos for some reason but if you look at all the photos you can see that there are two sections to the horn inside

 

[freddi]

so its folded and the first section of expansion points at the rear of the structure, giving a pretty long path

 

[Godzilla]

This is cool. It's like a folded back horn for a tweeter.

 

[bwaslo]

I am not able to post photos for some reason but if you look at all the photos you can see that there are two sections to the horn inside

Oop. You're right, I didn't catch that.

 

[GM]

Can I use it as a tweeter?

Well, the mouth area is around 800 Hz, so with a conical flare, >1600 Hz is OK if the driver will handle it once you either figure out the field coil supply required or replace the driver to a more modern one.

GM

 

[Rev. Billy Bob]

Wouldn't the sharp, nearly 180 degree bend filter out a lot of the higher frequencies?

 

[freddi]

there will be interference I think - ever put a tweeter compression driver on a Cobraflex horn? John Inlow warns of folded midbass horns and he's probably right even in that range. If the Utah's compression driver can be removed in non destructive way, then it should be easy to mount a modern driver then measure the combo.

 

[GM]

Yes, it's most likely designed to roll off the highest octave and maybe then some since tweeter horns were originally only required to work to 9 k or so due to signal limitations, so most vintage ones don't really go any higher without significant EQ and why supertweeters were developed to cover the > 5-7 kHz BW as the upper BW limit was extended.

GM