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Would you consider this an OB?
Would you consider this an OB?
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Old 21st October 2011, 12:49 PM   #1
talaerts is offline talaerts  Belgium
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Default Would you consider this an OB?

All, at 6 Moons they cover a speaker that interested me as it uses 4 FR drivers and a ribbon tweeter:

6moons audio reviews: J.A.F. Bombard

Click the image to open in full size.

The thing is, it is marketed as an innovative kind of open baffle.
Now, considering that there are 4 drivers, and a narrow open slit at the back, wouldn't it behave more like a bass reflex box?
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Old 21st October 2011, 12:58 PM   #2
tinitus is offline tinitus  Europe
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Would you consider this an OB?
Quote:
Originally Posted by talaerts View Post
The thing is, it is marketed as an innovative kind of open baffle.
--------wouldn't it behave more like a bass reflex box?
neither
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Old 21st October 2011, 02:12 PM   #3
Godzilla is offline Godzilla  United States
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I wonder how the slot contributes to the overall sound? At first i thought it would be interesting if the speaker opened and closed at the back to adjust the 'wings.'
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Old 21st October 2011, 02:14 PM   #4
norman bates is offline norman bates  United States
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I see it as an ob. That design would not have a double spiked Z-plot similar to a ported box.

I may have another future project.

Norman
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Old 21st October 2011, 02:51 PM   #5
Cal Weldon is offline Cal Weldon  Canada
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Would you consider this an OB?
It's a back loaded horn that uses a corner to complete the flare.
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Old 21st October 2011, 06:00 PM   #6
Godzilla is offline Godzilla  United States
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>>> It's a back loaded horn that uses a corner to complete the flare.

Like a BVR.

I hear ya Norman... i think it's a cool idea too.
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Old 22nd October 2011, 12:13 AM   #7
norman bates is offline norman bates  United States
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8" drivers don't have squat dispersion, so multiples (vertically) shouldn't interfere with each other. The hemptone climbs past 1khz (from posts I've seen), so that should help off axis not falling off too badly. And lastly the impedence of the tweet (and cap) stays low while the impedence of the fullrangers skyrocket as it goes higher, so the response of the fullrangers will be rolling (higher than if run wide open) off due to the energy flowing to the lower resistance load. And they use a coil to roll off some more from the woofs.

Seeing from earlier thread on "whizzers and intelligibility", I suppose we need the whizzer to help the off axis a bit past 2khz (for an 8" driver), but maybe use a flatish 8" but add a 3" phase plug ?

Neat neat idea. But how nicely does the hemptone do for 1-5khz ? That would be the question. People have liked them, but I'm not sure I want to drop $420 to find out. Maybe I'll run 4 x silver flute but add a phase plug. Then I'd need a stout tweet also (96db or so)

Norman
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Old 22nd October 2011, 01:39 AM   #8
chrisb is offline chrisb
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as wonderful as these may sound, and as "revolutionary" (my word) as this "proprietary folded version of the oldest 'patent' in loudspeaker construction" may be, it's pretty hard to think of it as an OB
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Old 22nd October 2011, 02:56 AM   #9
rjbond3rd is offline rjbond3rd
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Viewed from above, it's a tapered (~10-to-1) TL with a line length of ~12" and no driver offset

GM blew my mind with this:

Quote:
Originally Posted by GM View Post
Viewed another way, an OB is the inverse of a high gain TL, so as the long TL that only has the same pipe area as the driver's effective piston area (Sd) wants a strong motor (low Qts), the unfolded TL (OB) wants a proportionally weaker motor (higher Qts) and smaller baffle.
Link: http://www.diyaudio.com/forums/full-...ml#post2191638
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Old 22nd October 2011, 04:05 AM   #10
GM is offline GM  United States
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Quote:
Originally Posted by Cal Weldon View Post
It's a back loaded horn that uses a corner to complete the flare.
Yeah, what was once old is yet new again. As a standalone, it's ~aperiodically loaded like the Fonken series.

GM
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