We don't like diffraction slots for the most part- but look at the angles in this instance- very mild changes in the throat, and overall, relatively smooth from what I can tell in the pictures. For those of us with screw-on drivers that can play low like JBL 2426, these may be a good option for 500-5khz, particularly with a little effort on damping around the mouth, since the step there is a little more pronounced and there's no proper termination.
Inexpensive 500Hz (Claimed) horn
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Inexpensive 500Hz (Claimed) horn
We don't like diffraction slots for the most part- but look at the angles in this instance- very mild changes in the throat, and overall, relatively smooth from what I can tell in the pictures. For those of us with screw-on drivers that can play low like JBL 2426, these may be a good option for 500-5khz, particularly with a little effort on damping around the mouth, since the step there is a little more pronounced and there's no proper termination.Tags: None -
Non-buyouts- for repeatability/availability? I guess that makes sense as a "for the community" project- I tend not to think about it that way as even well known designers often only have a handful of people (if any) replicate their work, so I view posting designs as more of a thought exercise/creative outlet for the most part- but building a synergy is so much work I can see really wanting to have people be able to follow in your footsteps.Comment
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Agreed that it would be nice for others to follow. The other perspective is I'd like to try different divers without destroying what I built. Also the build process last time was pretty destructive, so having the ability to get more horns would be an advantage.Comment
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So, the good first- the throats are as smooth as they look. It's a very mild profile expansion at the first flare, done gently. There's a substantial amount of depth to them, which should help them operate lower.
The bad- the ridge closer to the mouth is pretty sharp.
The Ugly. Build quality. Some rough seams where sections were joined are the least of it. Cheap threads, a throat input that for some reason is angled (tapers into the throat instead of a step for the driver to couple to), plastic molten on the threads that made getting the driver properly screwed on a pain.
So there's definitely room for improvement, by lining the horn starting a bit before the mouth flare with some absorption, that ridge should be able to be mitigated. More material around and on the mouth itself would soften any edge diffraction. The throat can use some love, primarily with just smoothing the driver-horn interface (it's angled, so a little fillet of modeling clay would smooth it out).
They're not awful in terms of materials used, the threads may be bronze and the plastic is of okay enough quality. The throat is the hardest part and these seem to get that right (given using a little tweaking right at the driver coupling). I'm interested to see how they shake out when I get a mic on them.Comment
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So, I got the first of my 2374 delivered yesterday. The comparison is pretty stark. The two horns have a similar effective width and depth, but the 2374 is substantially larger, mostly due to the large flange/roundover, and a significantly larger vertical thanks to being a relatively straight, vs. stepped, expansion. Both do indeed load down into the 500hz region, but the 2374 maintains better pattern control both down low and up in the top octave.
The 2426 makes good sound on either, though, with an XO around 750 for the moment. Both need substantial shaping of the response, the 2374 moreso due to the more constant directivity (which mimics plane wave response)
Last edited by badman; 11-15-2019, 12:04 PM.Comment
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Added a pic with each horn, there's a bit of 30ppi foam stuck in the throat of the budget horn. No graphs to share just yet- need to gank them out of WT3 for impedance, and get a good acoustic measurement to share, right now I'm judging by moving the mic around and watching response changes. I actually was able to design a very functional XO pretty quickly that way last night, as you may be able to see I'm multi-amped, using a DBX Venu360. The horns, 15"s, and subs (dual 12"s per side hidden along the rear wall, the 15" enclosures hide them quite well!) are XO'd at 90 and 750.Comment
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At the end of the day, the mouth dimensions sort of dictate the lowest reasonable crossover, if pattern control is at all important to your design. I'll also point out that the horn has to reproduce significant sound for about an octave below its crossover point, assuming (say) a 4th order acoustic high pass response. I like it to have horn loading all the way down to that point.FrancisComment
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At the end of the day, the mouth dimensions sort of dictate the lowest reasonable crossover, if pattern control is at all important to your design. I'll also point out that the horn has to reproduce significant sound for about an octave below its crossover point, assuming (say) a 4th order acoustic high pass response. I like it to have horn loading all the way down to that point.Comment
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Agree totally. Horns should always be "oversized" relative to how they're typically used. 750 isn't an octave above where they fully unload, but the filters below cutoff are very steep on the horn side- there's a natural rolloff in power response of course, but also, because I'm active, at the moment it's actually 48db/o (Yes, I know there's drawbacks to super-steep filters). I have refinement left to do naturally, it's easy to do effective elliptical filters actively, and I can vary phase per-driver.FrancisComment
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Agreed. With how hard horns can be to integrate right, minimizing real overlap bandwidth, or at least controlling that range carefully, is much better than going simple textbook. I have to run steep regardless as I'm using the 2374/2426 instead of 2384/2453H-SL, so substantially higher diaphragm displacement for a given SPL (and thus LF is important to avoid). The 2426h is very robust but it's still only a 1.75" VC driver.Comment
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Agreed. With how hard horns can be to integrate right, minimizing real overlap bandwidth, or at least controlling that range carefully, is much better than going simple textbook. I have to run steep regardless as I'm using the 2374/2426 instead of 2384/2453H-SL, so substantially higher diaphragm displacement for a given SPL (and thus LF is important to avoid). The 2426h is very robust but it's still only a 1.75" VC driver.FrancisComment
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