I am looking to use my JBL2425 from 1kHz. 12dB slope. I will be using my flea amps, so no danger of damaging the driver even with only a 12dB slope.
There are many horns in that range, but I wonder if there is any benefit from using an over size horn? There are some horns with 1" entrances that go down to 500Hz, quite a few 800Hz.
I would still XO at 1kHz even if the horn cutoff is lower.
Any comments?
Any suggestions for a horn for this driver?
Ditto about a diy (wood) horn?
Thanks
There are many horns in that range, but I wonder if there is any benefit from using an over size horn? There are some horns with 1" entrances that go down to 500Hz, quite a few 800Hz.
I would still XO at 1kHz even if the horn cutoff is lower.
Any comments?
Any suggestions for a horn for this driver?
Ditto about a diy (wood) horn?
Thanks
I know a friend use the P-Audio PH-2513 and cut at about 900Hz for hifi with this driver. It's a short throw horn with a 90) horizontal x 65° vertical radiation pattern. The woofer used with it is a 12" Beyma SM112 and 4th order crossover at 900Hz (with dsp)
ok thanks. JBL horns are out of my financial reach.
Apparently a too low cut off gives a horn with higher distortion in the high end. But I'd think the low end benefits from the extra low extension of a bigger horn.?
Apparently a too low cut off gives a horn with higher distortion in the high end. But I'd think the low end benefits from the extra low extension of a bigger horn.?
JBL says you can cut it to 800Hz on low power (<70w). And it can work to 500Hz. So cutting it at 1kHz is no issue. I also did not hear distortion when i heared it at 900Hz crossover in the set of my friend. I would use a higher order crossover (active analog or dsp) with this altough and also put a cap tuned to 800 to 500Hz to protect your driver.
And a horn that tunes to low is no issue for a tweeter. It's done often, like in the unity horns and so. Better tuned to low then to high i think for horns for compression drivers.
Btw: that P-audio horn i mentioned is like 15€ max down here and used a lot for 1" compression drivers, even tuned higher than you would...
True, but XO'd an octave above a horn's rating = much less compression distortion due to being more of a WG over all of its BW.
The ATH4 designed ST260 is a free design to 3D print and is as good as it can get. Or ES800 by Joseph Crowe for more traditional design. Both are relatively easy prints and both work great with my DE500. The downside is that for great looks, you need to make a nice finish.
SemperFi,
1) A larger, lower cut-off horn will generally also have pattern control to a lower frequency.
2) Desired pattern would be helpful for suggestions.
3) The "Smith" DSH (Distributed Source Horn) is an easy to build DIY project, and also easy to convert to different horizontal angles and low frequency cut-off. It can be made to any finish you want, using aluminum fins with dark or hardwood or black paint top and bottom can really make a visual statement, or the horn can be hidden behind a grill.
Although some don't care for a diffraction based horn's sonic purity, the DSH does produce good sound, and was very popular in many homes and studio monitors from the 1950s through the 1970s.
It will also will make a JBL 2425 output near flat from cut-off to around 16kHz with little or no EQ required, simplifying crossover design.
Art
Attachments
Thanks all. The Smith horn sure looks like a fun project. Any known good plans out there? A quick search gives some poor scans of old prints.
The 2370 should be a good match in terms of throat angle, as they were used together in the 4671 model. Besides, the more or less flat response (picture) also reduces the EQ to a simple hi-shelf, which could be an advantage in a domestic application.
Here are 2D and 3D CAD files (Autocad format) in case the P-Audio copy is not available for some reason. Please rename the TXT files to .DXF after downloading.SemperFi said:
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This one looks pretty close to the original:
Reconstructed Smith Horn Plans
Just don't put the "plug" in, which was just an alignment in the original "Popular Mechanics" DSH plans.
Having used many variations of the Smith and the JBL 2370 and other bi-radials, not sure I'd have a decided preference for either, though building the Smith from wood is a lot (like four times) easier than a bi-radial.
Art
thanks. I will try and build the Smith Horn as the fins are similar to the ribs I used to make when I build model airplanes, way back. Should be easy enough.
This horn (see pdf) seems like a hybrid with 'smith' type throat going over to a different type of mouth (not sure what it's called).
This horn (see pdf) seems like a hybrid with 'smith' type throat going over to a different type of mouth (not sure what it's called).
The feature of the Smith is the mouth. The fins are found on horns with one fixed dimension and they create a narrow but expanding throat.
What you have there is a small Yuichi. It is a Hyp/Ex horn that has been held at 90 degrees horizontal.
What you have there is a small Yuichi. It is a Hyp/Ex horn that has been held at 90 degrees horizontal.
You have to have a JBL 2327 throat to use a 2425 with the 2397 horn.. it doesn’t work without it.
You can build the horn, also several sellers on Ebay making new ones, but the 2327 is a cast metal throat.
You can build the horn, also several sellers on Ebay making new ones, but the 2327 is a cast metal throat.
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If anyone is interested, it the attachment is a DXF file traced from the bitmaps (by hand). It is maybe not 100 % exact, but should be good enough. I am tempted to cut one on my CNC out of 12 mm plywood, the fins would be in two layers.