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In the Forum: Horn-Loaded Speakers
In the Thread: Chinese upperbass horn.
Post Subject: Greets, Romy.. I built some 48Hz straight horns... Posted by Jeffrey Jackson on: 8/14/2005
first post... but I recognize quite a few friends here..
so, my straight horns... I like them very much.. I built mine similar in style to what Greg B linked, but obviously much smaller.. mine are just under eight feet long (length of a sheet of plywood) and have a mouth roughly three feet by four feet each.. throat is nine inches by nine inches.. I used the ubiquitous EVM-12l as it's specs were just perfect for such a horn.. I have quite a few other drivers that I wish I would ever get to trying.. some nice field coil units. :^)
I LOVE the sound.. it does fall a bit short of what I wanted in the 200 to 300 Hz range, but I suspect that is the woofer.. I did have to add quite a bit of 1/4" all thread rod as bracing across the panels.. it worked very well... I also had to resize the back chamber (sealed) quite a few times to get the resonance down to the proper frequency.. it made a huge differerence...
The reason I think the driver is the weak point is because as a proof of concept I built a seven foot extension to them to try a JBL 2" exit compression driver - the alnico monster 2482... it sounded wonderful in the lower mids, but my initial throat expansion wasn't stiff enough and that came through in the blunting of bass transients in the 80 Hz area.. long horns have to be very stiff... it played quite flat down to 50, however...
you wouldn't fully approve of my system these days.. I am using a digital eq/crossover/delay unit to allow experimenting with lots of different horn and driver combinations.. it makes for quick learning, but, of course, the system sounds like it needs me to finish that phono stage and get vinyl spinning in my main room again..
I am currently listening to vintage alnico/phenolic RCA comperession drivers in the mids, and alnico/aluminum altecs for tweeters.. all horns homebrew.. I have a nice small lathe and a large lathe that needs a few improvements..
thanks for providing the forum...
Peace,
Jeffrey
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