| 4pi - like [message #62463] |
Sun, 02 May 2010 16:06  |
vladimir4
Messages: 22
Registered: May 2009
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Chancellor |
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Hello,
I'm trying to define my principal speakers based on 2225H and 2425H + 2370A and I'd like they covers 35Hz-16kHz in +- 3dB with an ability to shake the house for occasional parties.
For the 2225H I'm limited to dimension: 67" x 18" x 25" (w x h x d) and I plan to place the 2425H/2370A in a separate box on the top of this huge cabinet, at the ear level.
After a lot of reading my feeling is to build some kind of BLH or BIB - in order to get the adequate bass, and to cross the 2225/2425+2370A at 800Hz - to stay in great sounding area of both speakers.
As you are experts on use of the professional loudspeakers for the home hifi use, I'm open to any suggestion.
Thank you in advance,
vlad.
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| Re: 4pi - like [message #62491 is a reply to message #62489] |
Mon, 03 May 2010 19:36  |
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Wayne Parham
Messages: 18789
Registered: January 2001
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Illuminati (33rd Degree) |
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Crossover is not really at 1.6kHz, although I've called it that sometimes because that's the approximate corner frequency of the high-pass. Actual acoustic crossover is done where the horizontal directivity of the midwoofer and tweeter horn match, around 1.3kHz. There is naturally some overlap in that region where both woofer and tweeter are playing simultaneously, which is the cause of the vertical nulls, spaced about 25° above and below the forward axis. That's the position of the nulls with the drivers mounted as shown in the plans. If you move the sound sources further apart, the nulls draw closer together and compromise the forward lobe.If you're going to mount the horn outboard, I'd suggest moving the woofer up in the box so it's position is closer to the horn, maintaining the close vertical spacing between them. You can basically just flip the box over, and move the woofer up just a smidge, like an inch. This will allow you to position the tweeter directly over the woofer, instead of slightly offset to the left or the right to allow space for the port.
About the compression drivers, personally, I like the sound of the 2425 and 2426 but I think the DE250 sounds a little better. Both the JBL and the DE250 are very smooth sounding, but the JBL has a bit less output in the top octave. The DE250 is just as smooth to my ears but it has better reach. You get the shimmer without harshness, so its a win/win and since it costs less, I guess that makes it a win/win/win. Still, the JBL driver is very nice sounding and I've enjoyed several speakers with 2426 compression drivers.
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| Hornsubs verses direct radiators [message #62510 is a reply to message #62505] |
Wed, 05 May 2010 09:28 |
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Wayne Parham
Messages: 18789
Registered: January 2001
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Illuminati (33rd Degree) |
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I love horns, as you may know. And I think basshorns are some of the most challenging and exciting to build. The problem is, they have to be large to be good. That makes them difficult to use in a home hifi environment. Maybe in a batchelor pad or man cave. But when you can't have an absolutely huge box (at least 20ft3), I'd prefer bass-reflex boxes. In my opinion, a good direct radiator is better than a compromised hornsub, especially when you run them in a multisub arrangement.
All the physically small hornsubs I've seen come in two varieties: compromised efficiency or compromised response. Most of them have horribly peaky response, like 10dB peaks and valleys. I've seen a lot of hornsubs like that, popular because they're small and easy to build. But the response is terrible. Others use a horn/pipe approach, more a transmission line than a horn. That's fine, better than peaky response, in my opinion, but it comes with lower efficiency. They're pretty much the same as a bass-reflex box in terms of performance, but larger and more complex. I'd personally rather have a nice simple Helmholtz resonator.
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