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Old 20th September 2015, 08:19 PM   #11
tomchr is offline tomchr  Canada
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As far as I understand it, all drivers will exhibit cone breakup when standing waves develop across the cone. The only question is how well-controlled the breakup is. Larger cone -> lower frequency for the onset of breakup. You can usually tell from the data sheet when this happens as the directivity will start to suffer. This means the various SPL curves for, say, 15, 30, 45, etc. will start to diverge. This is all physics in action. The speaker driver designer is up against a pretty hard wall on that one.

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Old 20th September 2015, 09:26 PM   #12
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Jeff,

The 12PW might work for the lower midrange or as an extended midrange. But there is zero tolerance for cone breakup or the reported distortion issue of that driver at 500hz. Or any driver with audible cone breakup in its usable range, for that matter.
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Old 20th September 2015, 09:28 PM   #13
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Originally Posted by tomchr View Post
As far as I understand it, all drivers will exhibit cone breakup when standing waves develop across the cone. The only question is how well-controlled the breakup is. Larger cone -> lower frequency for the onset of breakup. You can usually tell from the data sheet when this happens as the directivity will start to suffer. This means the various SPL curves for, say, 15, 30, 45, etc. will start to diverge. This is all physics in action. The speaker driver designer is up against a pretty hard wall on that one.

Tom
Yes. The question is audibility.
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Old 20th September 2015, 10:34 PM   #14
chrisb is offline chrisb  Canada
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Yup, the 12PW is a decent wide band woofer by what I can hear

Dave -apologies to Bob, I must have conflated those tweets with the the ERT26 in my most recent micro-tower build- I've been a bit distracted lately
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Old 22nd September 2015, 06:55 PM   #15
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As far as I understand it, all drivers will exhibit cone breakup when standing waves develop across the cone. The only question is how well-controlled the breakup is. Larger cone -> lower frequency for the onset of breakup. You can usually tell from the data sheet when this happens as the directivity will start to suffer. This means the various SPL curves for, say, 15, 30, 45, etc. will start to diverge. This is all physics in action. The speaker driver designer is up against a pretty hard wall on that one.

Tom
Not sure I completely agree with you statements. Directivity is a matter of cone size vs. frequency. As the wavelength approaches the cone diameter, the driver will start to beam. As the frequency increases, beaming gets worse. It can be used to an advantage in certain designs.

I did not experience a beaming problem with the A10.2 or A10.3, but the cone breakup was "very evident" in both. I'm guessing breakup was around 400hz - 500hz, well below the 2Khz to 3khz point where beaming should start to kick in.

And some of the larger SEAS metal-cone drivers break up over 3K. That's well above the point where they start beaming.

Cone breakup and its severity seems to me to be more based on cone material. Beaming is generally cone diameter vs frequency. Two different animals.

Last edited by silverhairbp; 22nd September 2015 at 06:57 PM.
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Old 22nd September 2015, 07:05 PM   #16
chrisb is offline chrisb  Canada
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cone shape/profile also plays a significant factor in the calculus, particularly so in the case of wide band drivers without whizzers or phase plugs
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Old 24th September 2015, 02:08 AM   #17
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Tried the A7.3 last evening as a midrange / upper midrange. I've been generally satisfied with the driver in a 7.3 Pensil at low levels in a nearfield arrangement and was hoping that it would perform well at higher levels in a large system. But the ringing was evident, particularly on vocals. No a lot, but at an audible level.

If once I hear it, it will become an annoying distraction.
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Old 1st July 2016, 05:33 PM   #18
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I know this is an older thread, but if anyone's still around, would the sealed air cushion between a back to back driver isobaric setup control driver ringing?
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Old 2nd July 2016, 04:39 AM   #19
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How?

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Old 2nd July 2016, 04:58 AM   #20
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I tried an open baffle isobaric years ago, when a buddy gave me 3 weeks with 4 scanspeak revelators to play with.
What struck me was the unexpected lack of deeper bass, and the much improved detail throughout the midrange.
So I've wondered if that sealed cushion of air between the 2 drivers was cushiony (is that a word?) enough to maintain a cones wide pressure against the cones, damping resonances from their breakups.
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