The J horn is close to his size requirements and has potential to cover the range 150 to 1k he needs to cover. It's really not so big in the horn world. it's about as small as it's going to be to get where he is proposing to go.
Based on what 15" horn loaded drivers and horns you've used with what mid treble horn at what crossover frequency?
As an experiment I did this, and it made a huge improvement in the sound especially piano.
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First picture I've ever seen of the quadratic throat guide. Nice that the foam is flush with the surface.
I often wondered what a waveguide/horn made entirely of foam would sound like. Framework could easily be fabricated of steel rods to support a mounting plate and throat with the actual body being 1 1/2-2" thick open cell foam. The foam could be made rigid by drenching it in epoxy resin before final assembly.
The late Lee Neidow of the old "Bass List" had made foam horns for his speakers and claimed they were quite nice. I never heard them myself, so I can't say.
Best Regards,
TerryO
All the horns I have produced have been made of high density polyurethane foam. Not something that most people can do, it takes high quality tooling and expensive machinery to produce with these materials. Sounds like a carved wooden horn but you can do shapes that are very difficult to do with wood and not something you would do on a production basis.
I think the absorptive material wave guide is an interesting idea, somehow I recall I mentioned somewhere in the Geddes thread. Lot of ideas floating around.
To bring things down to Earth with a thump, both DDS DVB-15H and the Auto-Tech J-Horn (which looks an awful lot like an Altec A5/A7 horn) are off-the-shelf candidates for the 150 Hz to 700 Hz range. The DDS DVB-15H has a claimed efficiency gain of 3.5 dB, and I bet the Auto-Tech J-Horn is pretty close to that as well.
3.5 dB is just about the same efficiency gain as using a pair of 15" drivers in a vertical or horizontal array. In the working passband, the horn would be more directive than the twin drivers, but would also probably need some equalization, which erases part of the efficiency gain. (No, I'm not going to use digital equalization.)
Subjectively, I'm sure the horn and the array would sound different, maybe as a result of the different directivity patterns. Most direct-radiator loudspeakers are near-omnidirectional below 400 Hz, and the horn retains at least some pattern control an octave below that, so that's a big difference right there.
It's interesting that both bass horn and dipole loudspeakers have controlled directivity at low frequencies, which sets them apart from most other loudspeakers.
3.5 dB is just about the same efficiency gain as using a pair of 15" drivers in a vertical or horizontal array. In the working passband, the horn would be more directive than the twin drivers, but would also probably need some equalization, which erases part of the efficiency gain. (No, I'm not going to use digital equalization.)
Subjectively, I'm sure the horn and the array would sound different, maybe as a result of the different directivity patterns. Most direct-radiator loudspeakers are near-omnidirectional below 400 Hz, and the horn retains at least some pattern control an octave below that, so that's a big difference right there.
It's interesting that both bass horn and dipole loudspeakers have controlled directivity at low frequencies, which sets them apart from most other loudspeakers.
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Yes this is what I love about my array. It fills the room in a relaxed near-omnidirectional way. Works with every kind of music. Sound is more like the producer intended it to sound. But oh so dull. I am always a little happier with the midbass horns playing.
When you combine two 15's in an array and listen 8-15 feet back they interfere with each other when you cross them high. It's nasty interference to me but to each their own. Sure there are big dollar soffit mounted twin 15 hybrid systems that bandpass the 15's but they really aren't any more efficient then a single 15 they just have better bass.
The autotech horns appears to be more of a horn then the DDS, it should deliver more like 6 db gain in the upper bass low mid. Horns like the autotech work best with a driver that has a rising response like the JBL 2225
http://www.jblpro.com/pub/obsolete/2225hj.pdf
The autotech horns appears to be more of a horn then the DDS, it should deliver more like 6 db gain in the upper bass low mid. Horns like the autotech work best with a driver that has a rising response like the JBL 2225
http://www.jblpro.com/pub/obsolete/2225hj.pdf
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What is too high? I may end up with a 12db slope at 560Hz on my 12" drivers. Are you sure it is not just 15" drivers that can't go very high? Maybe you are experiencing comb filtering.
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Comb filtering = interference. The spacing from the 15s to the MF/HF section would be a problem sooner than the spacing between the two 15s. You can use this little program instead of doing the math: Tolvan Data
yes it's comb filtering interference- I like to keep twin 15's or lines of 15's below 300 cycles. A pair of 12's should be good to 400 or so I'd guess - keep them real close and use a sharp filter helps
Yes, but sometimes two problems are worse then one. the problem between the two woofers and then the problem between the two woofers and the mid horn - double trouble
If you use a driver that has a rising response there is no need for EQ, if you do venture into midbass horns try and get a driver that wll go to 1.2K flat in the horn because I think you'll find your mid horn will sound better crossed above 1K
Any midbass horn is going to have trouble getting up to 700Hz easily, especially if the lower cutoff is below 100Hz, or the driver is 15in. Inlow has a 100Hz horn that might get close using a 12in driver.
http://inlowsound.com/
http://inlowsound.com/