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In Reply to: RE: Choose a Low Pass posted by Bill Fitzmaurice on July 05, 2015 at 08:31:18
"The usual choice of the low pass frequency is based on where off-axis response falls off, typically by no more than 6dB at 30 degrees off-axis, while axial response is still flat."
Okay I get it. Can I ask you one question I've had for a while? What do you recommend as the upper cutoff for your horns, like the HT Tuba. The curves you post show 200hz and beyond, but I want to know it they go all the way up to 250hz?
Thanks,
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Big speakers and little amps blew my mind!
Follow Ups:
They go to 200Hz and beyond, but I wouldn't use them that high. As a general rule discreet subs should not be run high enough so that they're directionally locatable.
I would say in the context of this thread that they would be used as bass bins, not as discrete subs.
That brings us back to the choices of 140hz, 175hz, and 250hz. Which would you choose for the HT Tuba? Don't be coy.
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Big speakers and little amps blew my mind!
> That brings us back to the choices of 140hz, 175hz, and 250hz. Which would you choose for the HT Tuba?
No higher than 140Hz, as it was not designed with that intent. Horn loaded subs, or any horns for that matter, with parallel walls start to sound boxy if run too high. That's why my DR series of wide bandwidth horns have no parallel walls.
I like the sound of my HT Tubas crossed over at 160 Hz, but that is with a 96dB/octave crossover slope accomplished with a DEQX.
Thanks, that's an answer I can understand.
Your comments about parallel walls are interesting. I remember Bruce Edgar writing that folded horns should not have 90 degree angles. I look at my La Scalas and see lots of parallel walls.
For the benefit of the forum readers I will piece together a little horn system;
Use a BF DR-300 cab. It's 30" wide and that matches the width of the Danley Fig. 7 horn. You could probably cover 80hz to 15khz at -3db, and maybe 60hz to 20khz at -10db. That ain't bad for what is essentially a two-way speaker. Overall system efficiency would be around 108db.
Not too shabby if you ask me.
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Big speakers and little amps blew my mind!
Even 180 degree bends work fine, if properly configured. I wouldn't use the DR300 other than in its intended use, pro-touring PA. Even DR280 is overkill in a home, but there are those who like overkill.
Well the way I look at it; If you have a 30" wide mid horn, you might as well have a 30" wide bass bin. The space has already been set aside.
Let's see. The DR300 is about the size of the Klipsch Belle. The DR280 is the same size as my La Scalas.
Really I see your point. Might as well use the smallest DR250 and fill in the bottom with a sub. That's what most people would do with all three.
Myself, I could get by with two 80hz mid/bass horns and no sub. I could live with that. Not putting it forward as best.
Since I've got you on the line. Can I ask how high you would use your DR series? 350/400/500hz?
And that's the rub. These three low pass options are very low in my experience. There would be too much bandwidth overlap with a folded W horn. Wasted bandwidth really.
The solution for these crossover points I'm looking for are more like an HT Tuba at 140hz. That is; you are getting very close to the max top end of the bass driver. That should translate to good bass extension on the other end. Little or no wasted overlap. Why use a folded W horn to cover just 120hz to 250hz? Just one octave.
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Big speakers and little amps blew my mind!
> Can I ask how high you would use your DR series? 350/400/500hzThe DR200-280 woofer horns are good up to 2kHz, the DR300 up to 1.2kHz, but 31 band EQ is an absolute necessity. They are, after all, PA speakers, and in pro-sound 31 band EQ is SOP.
> To my knowledge no one has ever made a wide range acoustic horn sound good. Audiophile good.
Read this:
http://www.avsforum.com/avs-vb/showthread.php?t=1353217
Edits: 07/06/15
Yes I use a Yamaha 31 band eq for my Synergy-style horn. Have to. I prefer to go easy on the eq and cut but not boost. I'll just go with 500hz is okay.
Mr. Danley has proposed an acoustic horn that would cover something like 140hz to 15khz. That's more than two decades. That's what I meant by a wide-range acoustic horn.
Your DR280 would certainly be considered a wide-range acoustic horn at 100hz to 2,000hz. But that's only one decade and one octave. More than one decade is excellent by anyone's standards. But your horn would have to go from 100hz to 10khz to be comparable to Danley's proposed horn, which is theoretical.
Putting it in those terms I know you realize the enormity of the problem.
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Big speakers and little amps blew my mind!
> Your DR280 would certainly be considered a wide-range acoustic horn at 100hz to 2,000hz. But that's only one decade and one octave.
That's also just the woofer.
I realize that.
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Big speakers and little amps blew my mind!
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