Smoothest throat transition/frequency response in large pro coaxes? - diyAudio
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Old 18th September 2014, 01:18 AM   #1
wowo101 is offline wowo101  Germany
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Default Smoothest throat transition/frequency response in large pro coaxes?

Inspired by this kit: Point P25, I recently began researching 10" pro-sound coax drivers. What I found is that most of the available options still seem to exhibit severe discontinuities between CD, horn throat/center of the pole piece and cone – especially when compared to the highly optimized throat geometries and mouth terminations of e.g. the latest KEF and TAD/Pioneer HiFi coax drivers.

Some of the newer designs (e.g. Radian Audio | 5210 Coaxial Speaker or 0080 10CX650 - Coaxials 10CX650 : Eighteen Sound - professional loudspeakers) claim a smooth transition from CD to throat to cone, but they either show only heavily smoothed FR graphs that don't prove anything (Radian) or the graphs still seem pretty rough (18Sound) – and none of them has any detailed description or diagrams of the driver construction.

Does anyone have a recommendation for a driver that performs (at least reasonably) well in said respects? Or can someone point me to some more detailed information about the design and performance of the more well-known drivers of PHL, Radian, 18Sound et al.? Or maybe there's someone that even has measurements of them that are a bit more meaningful than the factory-provided ones?
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Old 18th September 2014, 03:55 AM   #2
winslow is offline winslow  United States
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Danley likes the B&Cs.
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Old 18th September 2014, 04:54 AM   #3
ErnieM is offline ErnieM  United States
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Also check out the BMS non-waveguided coaxs. Someone around here did measurements of most of the major brands and found them to be the smoothest.

The B&Cs don't look too bad either.
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Old 18th September 2014, 08:28 AM   #4
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"Smoothest throat transition/frequency response in large pro coaxes? "

For a coaxial speaker, if the cone is used as the horn, then the woofer pole piece must be machined to the correct throat shape.
If a separate horn is used in front of the cone, then the bottom throat of that horn can provide the correct shape directly down to the compression driver.

The Radian 5210, 5212, and 5215 coaxial datasheets document:
1) The compression driver mates directly to an identical diameter horn throat machined into the center of the LF pole piece. The horn flare is completed by the cone of the woofer, resulting in excellent polar response at mid range frequencies and beyond.
2) 90º Conical Dispersion


None of the other vendor commercial cone-horn datasheets mention a conical horn throat machined into the center of the LF pole piece.
SO, until specs of another coaxial speaker with a machined throat pole piece arrives, the Radian 5210 seems the one to beat.
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Old 18th September 2014, 04:00 PM   #5
winslow is offline winslow  United States
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All you have to do is look at the FR to see if there are a couple nasty dips in the treble to see how good the transition is...and you really can't do that with the Radian because of the overly smoothed graphs.

I like Radian products, but the shown FR is a bit of fiction IMO.
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Old 19th September 2014, 12:29 AM   #6
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Quote:
Originally Posted by winslow View Post
Danley likes the B&Cs.
If Danley is using B&C coax, they are not very smooth.

The graph below shows the 8" coax DSL SH100 frequency response with "15% smoothing", and my measured response without smoothing.
The 12" coax SM80 uses 18% smoothing, but looks even more ragged than the SH100.
Attached Images
File Type: png DSL SH 100.png (240.1 KB, 557 views)
File Type: png DSL SM 80.png (142.6 KB, 547 views)
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Old 19th September 2014, 02:32 AM   #7
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I believe he uses bms not b&c.
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Old 19th September 2014, 02:49 AM   #8
winslow is offline winslow  United States
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There is a video of the manufacturing plant here in NC out on the web, and you can clearly see the neo B&C 12s...and he has mentioned several times that when he was looking for a coax, the B&C's had the best horn to cone transition he had found at that time.

He does use the BMS 5 for another horn though.

Search his name and coax...it's out there.
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Old 19th September 2014, 02:54 AM   #9
winslow is offline winslow  United States
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Who is Danley Sound Labs - YouTube

Go to 4:08 mark and tell me that's a BMS coax...lol

And the SH-Mini has a 100 degree coverage pattern...same as the B&C, not BMS that is 90.

Last edited by winslow; 19th September 2014 at 03:01 AM.
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Old 19th September 2014, 03:28 PM   #10
wowo101 is offline wowo101  Germany
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Quote:
Originally Posted by weltersys View Post
If Danley is using B&C coax, they are not very smooth.
He wrote about his reasons for choosing the B&C Coax for the SH100 in a number places, including this: Help me pick a coaxial speaker ++ – there he says: "At the time I did the comparative measurements of the available driver choices, the B&C 8CX21 had the smallest acoustic / horn discontinuity between the cone and compression driver portion."

Weltersys's graph just confirms my initial impression – if that's what a coax with "the smallest acoustic / horn discontinuity between the cone and compression driver portion" gets us, then the state of things isn't really good in pro-sound coax world.

On the other hand, I think I read somewhere that Tom Danley made his comparisons back in 2008, so maybe things have changed since then?

Quote:
Originally Posted by winslow View Post
All you have to do is look at the FR to see if there are a couple nasty dips in the treble to see how good the transition is...and you really can't do that with the Radian because of the overly smoothed graphs.

I like Radian products, but the shown FR is a bit of fiction IMO.
My point exactly – and the less smoothed graphs of newer designs from 18Sound et al. still seem pretty ragged.
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