I recall an article about using drivers on horns with smaller entrances than the driver exit in the old EV PA Bible. They said it was a bad idea and showed a response chart with a very rough response compared to the same driver on a proper horn.
I recall an article about using drivers on horns with smaller entrances than the driver exit in the old EV PA Bible. They said it was a bad idea and showed a response chart with a very rough response compared to the same driver on a proper horn.
In Dr. Harry F. Olson's book Elements of Acoustical Engineering, a restriction in a pipe is modeled as being analogous to a series inductor in an electrical circuit. An accompanying graph shows a steeply declining high frequency response.
The effects of using a 1" to 2" adapter in reverse might be quite severe, as the cross section would reduce from 3.14 square inches to .79 square inches, a 75 percent reduction. My guess is that this might alter the driver loading in a frequency dependent way in addition to the h.f. rolloff. Not good.
Putting a glorious large format driver on an undersized high frequency horn doesn't seem like a good idea to me anyway, aside from the reverse throat issues. I discovered about 13 years ago that midrange compression drivers sound best on really large horns, much bigger than are normally used in commercial products except for stadium and theatre sound applications. I went through a succession of Altec and RCA 500Hz. and 300Hz. multicellulars until I discovered the fine listening properties of conical (straight sided) horns. These can require some EQ for flat response, but sound the least horn-like and offer a thrilling listening experience.
I am now using some homebrew rectangular conicals, about 32" long with a mouth of 24" by 32". You should try throwing together a pair of these from cheap plywood and give them a listen!
Steve
Show some pics of your horns
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