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Old 6th May 2010, 01:52 AM   #21
soongsc is offline soongsc  Taiwan
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I don't think you can get anything for live performance within 9KG.
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Old 6th May 2010, 04:48 AM   #22
ScottG is offline ScottG  United States
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Quote:
Originally Posted by Dogue View Post
In this design would it be advisable to have a tweeter to make up for the loss of highs by placing the B200 off axis?

And, relating to my earlier question, would the B200 be able to handle power from an instrument amp?
No tweeter.. The driver is full-range and has a strongly elevated treble region (which should offset its use as a "walsh" driver). You might need a shelving network however to "flatten-out" the response, but it really depends on how the driver behaves when listened to inverted as a radial driver (..or "walsh" style).

The driver can handle 32 watts continuous, 64 peak. That amounts to 15db of gain from the 90 db average of the driver, or 105 at 1 meter (108 peak). This isn't it's *linear* range, but an increase in harmonic distortion shouldn't be a problem for your intended use. The amplifier could have 1000 watts at 8 ohms; the only real requirement is that it has 64 watts for the 5 to 6 ohms (nominal) of the driver.
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Old 6th May 2010, 08:44 AM   #23
el`Ol is offline el`Ol  Germany
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The 12" Beyma has an EBP (Fs/Qe) of 70. In my simulations the 12" B&C fullrange and the 8 Ohm Ciare with an EBP of 160/150 were already a bit too weak. One could try a larger cross-section with these drivers, but then the size becomes unmanagable.
From the specs (if one can trust those at the Lowther website) the Lowther PM2C would be OK, but 1) ridiculously expensive an 2) maybe too low displacement to deliver enough bass.
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Old 6th May 2010, 09:34 AM   #24
el`Ol is offline el`Ol  Germany
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Quote:
Originally Posted by Dogue View Post
In this design would it be advisable to have a tweeter to make up for the loss of highs by placing the B200 off axis?

And, relating to my earlier question, would the B200 be able to handle power from an instrument amp?
I had very natural results (even more natural than with the reflector cone) with a similar driver (Ciare HX201) facing the ceiling without any correction. The treble rise is compensated by the reflection loss. But from theory with a delay higher than 20 ms the ceiling reflection is perceived as an echo and the two frequency responses are no longer combined. The direct sound is perceived as lacking treble then. Could be a problem in large auditoriums. The HX201 is capable of delivering 8-9 dB more SPL than the Visaton. In theory it works in a reasonably sized BR enclosure, but people were not so happy with it (displacement?). It became popular in Germany as driver in a really large and heavy horn (facing the listener and corrected).
If you mount the driver inverted what you get is more a midwoofer than a fullrange driver.
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Old 6th May 2010, 03:51 PM   #25
Dogue is offline Dogue  United States
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Originally Posted by el`Ol View Post
I had very natural results (even more natural than with the reflector cone) with a similar driver (Ciare HX201) facing the ceiling without any correction.
To clarify, this was mounted in a standard fashion, in the enclosure, rather than with exposed sides (like a reverse Walsh)?
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Old 6th May 2010, 04:02 PM   #26
Dogue is offline Dogue  United States
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Thanks, everyone, for the further thoughts.

I wish I knew more, and I also wish I had more resources available so that I could experiment at will.

The main designs proffered appear to be:

1) Full-range pointed up, with or without diffuser
2) Full-range pointed down, like a Walsh driver

The main question is, given limited resources, which design has the greatest chance to succeed in this application?

To summarize and clarify:

I am seeking similar output capability as my current keyboard amp, which is rated at 2x50W, going into 2 Eminence Alpha 8s (125W RMS / 250W music) and 2 80W 3.5x3.5 horns.

I am considering using as an amplifier something like this: 41Hz Audio:AMP10-BASIC kit which is rated at 2x60W at 8 ohms.

This will be most often used it small to medium-sized rooms and performance spaces. For large spaces I would just use a house PA.

Omni-directionality, frequency response around 60-18000Hz, relatively low cost, ease of construction, and being lightweight are other primary concerns. Thanks again for all suggestions; I'm sorry I do not know more, and I appreciate as much detail as you can provide.

(As we now seem to be talking full-range, mods, please feel free to move this thread).
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Old 6th May 2010, 07:37 PM   #27
Ron E is offline Ron E  United States
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Why not just mount your pair of eminence speakers with a back corner together and the fronts facing at different angles? If this gets you what you want, think about DIY...
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Old 6th May 2010, 07:56 PM   #28
MaVo is offline MaVo  Germany
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Maybe something like this? Solid Acoustics dodecahedron speakers Should solve the low spl problem of fullrangers, since you will use 12
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Old 6th May 2010, 08:10 PM   #29
el`Ol is offline el`Ol  Germany
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Quote:
Originally Posted by Dogue View Post
To clarify, this was mounted in a standard fashion, in the enclosure, rather than with exposed sides (like a reverse Walsh)?
Standard mounting, driver on ear-height, facing the ceiling, no reflector, sealed enclosure, TQWT, later very large open back enclosure together with a 15" bass driver.
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Old 6th May 2010, 09:10 PM   #30
el`Ol is offline el`Ol  Germany
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I just see the Tangband W8-1772 is much cheaper in the US than over here.
Parts-Express.com:Tang Band W8-1772B 8" Neodymium Full Range Driver | Tang Band W8-1772 8" Full Range Driver full range tb speakers neodymium driver line array point source midrange home theater computer speaker center channel set tube amplifier
It has a strongly rising frequency response, good for ceiling flooding. Displacement is more than usual for a fullrange driver, and with an enclosure size of merely 40 l a BR should do the 60 Hz. Port dimensions would be 4" diameter, 5" length. I took the measurement data of the K+T magazine, where the Qts is a bit higher than the value published by the manufacturer. Sensitivity is comparable with the Alpha-8 and two of these enclosures are still quite small. It has 60 W max, not RMS, but if your music has dynamics and you don't use the amps to fight loudness wars this should be OK.

Last edited by el`Ol; 6th May 2010 at 09:21 PM.
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