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Author Topic: B&C 14" coax for wedges ?  (Read 5177 times)

Uwe Riemer2

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Re: B&C 14" coax for wedges ?
« Reply #10 on: February 13, 2019, 01:45:21 PM »

That was a part of what prompted me to ask if anyone had experience with these coaxes.  The fact that they are depending on the cone surface as a waveguide extension for the HF is not encouraging.

Well, Danley uses a 12" cousin and we all heard, how capable this box is.

I cannot tell you something about this specific driver, but I have designed a wedge with the 14CXN76.
My box is good, as long as I dont need serious ( 3x 4x12" Marshall on stage ) kick and snare out of it.

So if you want to wait a year or so, I am pretty sure, that I will have an opinion about the 14CXN88
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Riley Casey

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Re: B&C 14" coax for wedges ?
« Reply #11 on: February 13, 2019, 07:52:56 PM »

Only way to find out is to rattle Bennettís cage.  No retail links coming up.  Makes me think itís not getting a lot of traction.

Frank Koenig

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Re: B&C 14" coax for wedges ?
« Reply #12 on: February 13, 2019, 09:01:38 PM »

The fact that they are depending on the cone surface as a waveguide extension for the HF is not encouraging.

Riley, I'm not sure where you're getting that. I'm not a driver designer but I have built systems around three modern coaxes, two of which have rigid horns that extend beyond the woofer dust cap and one where the horn melds into the woofer cone, as is the case with this diver and the similar one that Danley uses in the much celebrated (here at least) SM80. I've also looked at a lot of published response curves. My observation is that the coaxes with protruding horns have less overlap between the passbands and are generally more challenging to design crossovers for.

I presume the extended horn can get you a narrower pattern at the highest frequencies and perhaps a bit more efficiency. But given that newer B&C (as well as other) HF compression drivers can get stupid loud and sound pretty good doing it, horn efficiency sufficient to keep up with a single 12 to 15 in. cone driver is not likely an issue. (The SH96 uses a single B&C Ti diaphragm driver in a conical horn crossed at ~1kHz to keep up with 4 15 in. woofers, for example.) To be sure, these coax speakers are used in applications where precise, wideband pattern control is not required.

Way back in the day I believe Urie built a studio monitor around the Altec 604 coax. They ended up cutting holes in the walls of the HF horn to get it to work. I've got a paper on it somewhere that I can dig up if anyone is interested.

Something I've wondered about is whether using the woofer cone as part of the HF horn results in any funny sort of frequency/phase modulation distortion as the horn walls move a significant fraction of a wavelength when the woofer is working at high level. It appears not to be a problem in practice but I'd be interested to hear any observations on this.

I'll be looking at this driver when I next get the speaker building bug.

--Frank
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"Nature abhors a vacuum tube." -- John Pierce, Bell Labs

Uwe Riemer2

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Re: B&C 14" coax for wedges ?
« Reply #13 on: February 14, 2019, 03:42:23 AM »

...  No retail links coming up.  Makes me think itís not getting a lot of traction.
That is easy to explain:
The price of the 88 is 30% more than the 76, which puts it beyond the wallet of most DIY folks,
there are not many like Peter Morris.
And then you will need an amp to exploit the low/mid capabilities , for me that means 44M10, Delta 100DSP, PLM12K44
also not exactly cheap

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Helge A Bentsen

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Re: B&C 14" coax for wedges ?
« Reply #14 on: May 17, 2021, 10:05:00 AM »

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John Halliburton

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Re: B&C 14" coax for wedges ?
« Reply #15 on: May 18, 2021, 08:54:31 AM »

Old thread alert!

B&C has a design for this driver.
https://www.bcspeakers.com/media/W1siZiIsIjIwMjEvMDIvMDIvMTVfNDdfMTFfNjMyX0NYMTQucGRmIl1d

I like the polar projections, no major pinching in coverage at certain frequencies.  Some get nasty at times.

Best regards,

John
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Riley Casey

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Re: B&C 14" coax for wedges ?
« Reply #16 on: May 18, 2021, 09:16:17 AM »

Yup, I'm exploring the mysteries of turning out documentation for a modified version to send to a local CNC shop to make flat pack parts for the two B&Cs I bought before the world changed.  I'm not sure their choice of 1800 hz for a crossover point isn't based more on reducing warranty clams than on the best performance at least based on my testing of the drivers. 1100 Hz low pass and 1250 high pass 4th order was the sweet spot for me.

Old thread alert!

B&C has a design for this driver.
https://www.bcspeakers.com/media/W1siZiIsIjIwMjEvMDIvMDIvMTVfNDdfMTFfNjMyX0NYMTQucGRmIl1d

Jim McKeveny

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Re: B&C 14" coax for wedges ?
« Reply #17 on: May 18, 2021, 09:57:51 AM »

I'm not sure their choice of 1800 hz for a crossover point isn't based more on reducing warranty clams than on the best performance at least based on my testing of the drivers. 1100 Hz low pass and 1250 high pass 4th order was the sweet spot for me.

Nice thing about coax's is eliminating the time alignment needs. This also makes passive crossover an option. The asymmetry in the crossover is also do-able passively. Many amps w/dsp don't allow it. Where are you headed with this?
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Helge A Bentsen

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Re: B&C 14" coax for wedges ?
« Reply #18 on: May 18, 2021, 10:30:25 AM »

Yup, I'm exploring the mysteries of turning out documentation for a modified version to send to a local CNC shop to make flat pack parts for the two B&Cs I bought before the world changed.  I'm not sure their choice of 1800 hz for a crossover point isn't based more on reducing warranty clams than on the best performance at least based on my testing of the drivers. 1100 Hz low pass and 1250 high pass 4th order was the sweet spot for me.

Interesting, please keep us updated with your progress :)
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Peter Morris

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Re: B&C 14" coax for wedges ?
« Reply #19 on: May 19, 2021, 02:11:46 AM »

I suspect this project is capable of producing a great result with the correct processing. Easy to see why ;-)
« Last Edit: May 19, 2021, 08:01:50 AM by Peter Morris »
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Re: B&C 14" coax for wedges ?
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