Pair of Beyma 15XA38ND Pro Coaxial Woofers with Compression Tweeters. One Pair Only, like new, used for a few hours of testing. Woofers rated at 350 watts AES, 700w program; tweeters rated at 90 watts AES 180W program. Woofers 8 ohms, tweeters 16 ohms. Powerful lightweight neodymium magnets.
I tested these for use in the Bitches Brew Live Edge Dipoles (link goes to forum thread here on DiyAudio) to cover the range 110Hz to 20KHz. I ended up choosing the B&C 15CXN88's instead, which are 2X as expensive, because the B&Cs have a more consistent directivity pattern than the Beymas from 4K to 7K.
For applications where you want a Coax (ie Tannoy concentric) these drivers are superb and also quite affordable. New units sell for a good bit more.
They can be used as a bass-mid in Open Baffle; with a good bit of EQ they could be used Open Baffle down to about 50Hz in a U-shaped configuration like you see here; in a reflex or transmission line they will go down to 30Hz with 115dB+ output.
WOOFERS 15 inch, 98dB SPL, Fs 38Hz, 6.7 ohm DCR, Qms 6.4, Qes 0.31, Qts 0.30, Vas 238 liters, BL 20.4, Sd 880 cm^2, Xmax 6mm. 4 inch voice coil. See the manufacturer's data sheet for frequency response and impedance curves. Outside diameter 15.28 inches, cutout 13.85 inches.
I used these in a bi-ampified active system with MiniDSP digital crossovers. They sound absolutely fantastic. For my final design I opted for a B&C 15CNX88 driver with slightly wider dispersion pattern. The dynamic range is spectacular and the sonic texture is silky-smooth with a good crossover design.
The tweeters have an incisive, detailed and sharply focused timbre. If you want a tight sound radiation pattern with strong directional control, these are ideal. Perfect for creating Tannoy-style or Constant-Directivity Open Baffle (dipole) high-end monitors. Excellent for stage monitors and compact professional sound reinforcement speakers in churches and auditoriums.
$749 / pair plus shipping.
I only ship to the lower 48 states in the USA.
I tested these for use in the Bitches Brew Live Edge Dipoles (link goes to forum thread here on DiyAudio) to cover the range 110Hz to 20KHz. I ended up choosing the B&C 15CXN88's instead, which are 2X as expensive, because the B&Cs have a more consistent directivity pattern than the Beymas from 4K to 7K.
For applications where you want a Coax (ie Tannoy concentric) these drivers are superb and also quite affordable. New units sell for a good bit more.
They can be used as a bass-mid in Open Baffle; with a good bit of EQ they could be used Open Baffle down to about 50Hz in a U-shaped configuration like you see here; in a reflex or transmission line they will go down to 30Hz with 115dB+ output.
WOOFERS 15 inch, 98dB SPL, Fs 38Hz, 6.7 ohm DCR, Qms 6.4, Qes 0.31, Qts 0.30, Vas 238 liters, BL 20.4, Sd 880 cm^2, Xmax 6mm. 4 inch voice coil. See the manufacturer's data sheet for frequency response and impedance curves. Outside diameter 15.28 inches, cutout 13.85 inches.
I used these in a bi-ampified active system with MiniDSP digital crossovers. They sound absolutely fantastic. For my final design I opted for a B&C 15CNX88 driver with slightly wider dispersion pattern. The dynamic range is spectacular and the sonic texture is silky-smooth with a good crossover design.
The tweeters have an incisive, detailed and sharply focused timbre. If you want a tight sound radiation pattern with strong directional control, these are ideal. Perfect for creating Tannoy-style or Constant-Directivity Open Baffle (dipole) high-end monitors. Excellent for stage monitors and compact professional sound reinforcement speakers in churches and auditoriums.
$749 / pair plus shipping.
I only ship to the lower 48 states in the USA.
Very tempting.
Although I don’t think these will work in a small space. I’ve been searching for an active diy speaker build for quite some time. I would consider using these open baffle utilizing the “bitches brew” design.
Your thoughts please.
Although I don’t think these will work in a small space. I’ve been searching for an active diy speaker build for quite some time. I would consider using these open baffle utilizing the “bitches brew” design.
Your thoughts please.
@intojazz Hi, can you tell me what a "small space" is in your situation? Do you have a specific frequency range requirement? Have you decided what kind of baffle to use? You might be able to use dipole or acoustic suspension with this driver in a very compact design, depending on your EQ situation. Is active EQ possible? Active or passive crossover? Will 1 cubic foot work for you?
@intojazz I'm going to make some guesses based on what you briefly mentioned, I'm assuming that you would be willing to try these with a small dipole and active EQ. Above I linked to this system I built a few years ago:
"Live Edge Beryllium Dipoles"
https://psma-website-assets.s3.amazonaws.com/live_edge_beryllium_dipoles.pdf
Imagine making a similar system but with the Beyma coax instead of separate tweeter.
The smallest you could make with the 15XA38NDs would be a baffle about 20" x 20" and you could make a u-frame maybe as little as 10" deep, which would extend the low end some. That system would start rolling off at around 150Hz. If you wanted it to go down to 50Hz you would need about +15dB of EQ to make it sound right.
The system linked above goes down to 40Hz and has +17dB of EQ.
If you made a cabinet identical to the Live Edge Beryllium Dipoles [36H x 18W x 12D] you could run these down to 40Hz, because the overall limitations would be identical. Both woofers have roughly the same output capability.
Take a close look at the PDF linked above and see the electronic EQ graph near the end. The +17dB bass boost around 40Hz (referenced to 500Hz) sounds a little ridiculous to the mindset of the average speaker designer, but please remember a few things:
1) these drivers have natural SPL of 97-99dB to begin with, they are super efficient. This means that the extra power is only needed between 50-80Hz and even after EQ they are not really that inefficient compared to any other speaker. In fact they are as efficient as the laws of physics allow them to be, regardless of baffle type.
2) These drivers can move a lot of air because a 15" woofer has a lot of surface area (880 cm^2) and the Xmax is about 6mm. So they will play fairly loud - as loud as the typical "stereophile reader" probably wants them to play, anyway.
For my personal tastes, the Beryllium Dipoles play almost as loud as I ever want them to play. If a song has got lots of bass and heavy drums they do sound strained at high volumes; and they don't have any "super deep below 40Hz" bass. They do have enough bass to satisfy 90% of rock and jazz. They don't sound like anything is obviously missing unless you're listening to a recording that you already know has 25Hz super low bass.
If you have a 25-50 watt amp that will be enough. You just need active EQ as in MiniDSP or similar to pull it off.
So yes you could make a compact version similar to the Live Edge Beryillium Dipoles and you will find that the Beyma coax arrangement gives great stereo imaging and the crossover can be very seamless. I recommend 1200-1500Hz crossover.
You will need to run measurements to get the EQ the way you want it, as any coax / horn driver combo is going to have to be "tamed" in order to work well.
If you add a muscular sub with a 80hz crossover, then they will easily run down to 80Hz with a little EQ boost around 100Hz, AND play as loud as most people would ever want. They're so efficient you could use a 3 watt single ended tube amp and they would probably play loud enough with a separate powered sub.
My experience is that high efficiency speakers produce a realism and dynamic expression that low efficiency speakers can't match and that's part of the magic of using these pro drivers.
"Live Edge Beryllium Dipoles"
https://psma-website-assets.s3.amazonaws.com/live_edge_beryllium_dipoles.pdf
Imagine making a similar system but with the Beyma coax instead of separate tweeter.
The smallest you could make with the 15XA38NDs would be a baffle about 20" x 20" and you could make a u-frame maybe as little as 10" deep, which would extend the low end some. That system would start rolling off at around 150Hz. If you wanted it to go down to 50Hz you would need about +15dB of EQ to make it sound right.
The system linked above goes down to 40Hz and has +17dB of EQ.
If you made a cabinet identical to the Live Edge Beryllium Dipoles [36H x 18W x 12D] you could run these down to 40Hz, because the overall limitations would be identical. Both woofers have roughly the same output capability.
Take a close look at the PDF linked above and see the electronic EQ graph near the end. The +17dB bass boost around 40Hz (referenced to 500Hz) sounds a little ridiculous to the mindset of the average speaker designer, but please remember a few things:
1) these drivers have natural SPL of 97-99dB to begin with, they are super efficient. This means that the extra power is only needed between 50-80Hz and even after EQ they are not really that inefficient compared to any other speaker. In fact they are as efficient as the laws of physics allow them to be, regardless of baffle type.
2) These drivers can move a lot of air because a 15" woofer has a lot of surface area (880 cm^2) and the Xmax is about 6mm. So they will play fairly loud - as loud as the typical "stereophile reader" probably wants them to play, anyway.
For my personal tastes, the Beryllium Dipoles play almost as loud as I ever want them to play. If a song has got lots of bass and heavy drums they do sound strained at high volumes; and they don't have any "super deep below 40Hz" bass. They do have enough bass to satisfy 90% of rock and jazz. They don't sound like anything is obviously missing unless you're listening to a recording that you already know has 25Hz super low bass.
If you have a 25-50 watt amp that will be enough. You just need active EQ as in MiniDSP or similar to pull it off.
So yes you could make a compact version similar to the Live Edge Beryillium Dipoles and you will find that the Beyma coax arrangement gives great stereo imaging and the crossover can be very seamless. I recommend 1200-1500Hz crossover.
You will need to run measurements to get the EQ the way you want it, as any coax / horn driver combo is going to have to be "tamed" in order to work well.
If you add a muscular sub with a 80hz crossover, then they will easily run down to 80Hz with a little EQ boost around 100Hz, AND play as loud as most people would ever want. They're so efficient you could use a 3 watt single ended tube amp and they would probably play loud enough with a separate powered sub.
My experience is that high efficiency speakers produce a realism and dynamic expression that low efficiency speakers can't match and that's part of the magic of using these pro drivers.
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Perry,
To answer your questions:
The room is 13’x13’x8’ and I sit about 6 ‘ from the speakers. Frequency range 50 hz to 20 khz, although I’m not sure how good my hearing is. Baffle type probably just go with baltic birch at 1 1/2”. I’m not looking for pretty, just suitable.
I’ve never heard a dipole. MiniDsp 2x4 HD for sure. I currently use a Pass F6 class A at 25 watts per channel and my source is a cdp or a Mac. 50’s and 60’s Jazz is what I listen to most but appreciate blues , classic rock and many other genres. I rarely listen at high volume so details at low volume is important.
The coax dipole triangles with the Faital 12HX 230’s look interesting.
I appreciate your considerable response
To answer your questions:
The room is 13’x13’x8’ and I sit about 6 ‘ from the speakers. Frequency range 50 hz to 20 khz, although I’m not sure how good my hearing is. Baffle type probably just go with baltic birch at 1 1/2”. I’m not looking for pretty, just suitable.
I’ve never heard a dipole. MiniDsp 2x4 HD for sure. I currently use a Pass F6 class A at 25 watts per channel and my source is a cdp or a Mac. 50’s and 60’s Jazz is what I listen to most but appreciate blues , classic rock and many other genres. I rarely listen at high volume so details at low volume is important.
The coax dipole triangles with the Faital 12HX 230’s look interesting.
I appreciate your considerable response
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Yes the Faital 12” triangles would be very similar except the Beymas will have more bass output. Your amp situation sounds great. Your room is pretty similar to mine. Baltic birch is a good choice.
Hi Perry,
clarifying: you are pitching these drivers as a single driver solution on open baffle w/ DSP to help balance out response? If I'm interpreting that correctly, what does the (2) way dipole that you designed achieve that the single Beyma driver is unable to deliver? FYI - i'm not far from you & have been considering building one of your designs for a while now....
clarifying: you are pitching these drivers as a single driver solution on open baffle w/ DSP to help balance out response? If I'm interpreting that correctly, what does the (2) way dipole that you designed achieve that the single Beyma driver is unable to deliver? FYI - i'm not far from you & have been considering building one of your designs for a while now....
@soltung yes the Beyma is a single driver solution for an OB with DSP. Pros and cons:
The Beryllium dipoles with SB29 waveguide tweeter are a good deal more expensive to build (2X) and they are excellent. The Be SB tweeters are better than the Beyma tweeters.
The Beymas are less expensive and have the coax advantage of not having lobing problems in the crossover region.
The reason that I chose the much more expensive B&Cs for the Bitches Brew is that the Beymas have a somewhat erratic radiation pattern in the range of 4K to 7K. The Beyma tweeters are sort of omnidirectional across that range instead of being constant directivity with a narrow horn pattern. It’s not a big problem, and in fact, most people would never think about it or notice, but the B&C is better in that regard. I don’t know of any other 15 inch coaxial with a high build quality that you can buy for the price of the Beyma.
Re being local you can message me. Also doing an open house for the Chicago Audio Society on June 25 2023 and will be showing off several of these designs.
The Beryllium dipoles with SB29 waveguide tweeter are a good deal more expensive to build (2X) and they are excellent. The Be SB tweeters are better than the Beyma tweeters.
The Beymas are less expensive and have the coax advantage of not having lobing problems in the crossover region.
The reason that I chose the much more expensive B&Cs for the Bitches Brew is that the Beymas have a somewhat erratic radiation pattern in the range of 4K to 7K. The Beyma tweeters are sort of omnidirectional across that range instead of being constant directivity with a narrow horn pattern. It’s not a big problem, and in fact, most people would never think about it or notice, but the B&C is better in that regard. I don’t know of any other 15 inch coaxial with a high build quality that you can buy for the price of the Beyma.
Re being local you can message me. Also doing an open house for the Chicago Audio Society on June 25 2023 and will be showing off several of these designs.
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Thanks Perry - I'm putting that date on the calendar. I'm looking forward to it, provided my schedule remains clear. Your Live Edge Dipoles have been on my radar for some time as a potential project.