Beyma 12CX - PA only of usable for hifi ?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi !


I'm thinking of buying Beyma 12CX co-axial speakers,
but I cannot seem to find any 'user-reviews' on the internet

I can however find stuff like guitar-cabs, PA-monitor use,
and some guys who have them in Karlson enclosures.
But are they usable as quality hi-fi speakers ?

I plan to use them on single ended triodes

If you have / had them, please tell me what you think of 'em,
and please tell me what cabinets you use(d)


Cheers,

Empee
 
I haven't heard this driver, but judging from the datasheet only the raw responses from the drivers seem a bit problematic for Hi-Fi use. The tweeters response falls too early to be crossed over low enough to the 12" midrange.

In order to achieve reasonable off-axis response you generally need to cross these large coaxials in the 1-1.5 kHz region.

If you want a ridiculously cheap and acceptably sensitive 12" coaxial, the finnish website audiovideo.fi recently published a series of DIY-loudspeakers based on the Eminence Beta coaxials, including the 12" Beta 12CX, which also gave the best sound quality of them all. I haven't yet heard this, but the editor told me it is surprisingly good sounding.

For something a bit more exotic (read: expensive) I've had quite good results with the BMS 12C362, but I will not recommend it until I've heard it head on with the Eminence, costing about a quarter of the BMS's price. I want to know whether the BMS really justifies spending the extra dosh.
 
Moderator
Joined 2002
Paid Member
As one example, Emerald Physics uses the driver in the CS2.7, which is in itself an upgrade from the CS2.3, which uses the Beta 12CX.

I've heard both and I prefer the Beyma. It has slightly lower distortion, IINM because it sounds smoother. Unfortunately this driver does not work on open baffle without bass support as the Q is too low (thus the absence of an upgrade to the CS3.0 which continues to use the Beta). Both speakers use a custom crossover between the drivers, and I could certainly not hear anything that indicated very high levels of distortion. I suspect some crossover work is necessary to get the best out of these.

The Eminence driver is good too, but the APT50 is even worse than the Beyma's compression driver wrt a low crossover point, it does not like to be crossed below 3k, ideally 4k. This can be somewhat avoided by using a different compression driver.

Both have the nasty 10k dip inherent to these kind of coaxials due to the discontinuity in the throat. There is some EQ required to smooth response of both drivers, the EP speakers are accompanied by a Behringer DCX 24/96 for this purpose.

The big advantage of the Beta is that you can buy it (at least here) without the compression driver and use one of your choosing. For the Beyma, it comes pre-fitted and sold as a single driver unit.
 
Still surprisingly the designer was able to cross the APT50 at a low enough crossover point for the 12". And the crossover region looks quite clean. The big dip centered at around 8kHz is still there, of course, but is absent from the off-axis response, which is probably what saves the sound in real life listening.

It's only in finnish, though, but you can find the crossovers and responses from here:

Kaiutinrakennusohje Yksisilmäiset veljekset - hifi-PA-kaiuttimet Eminence Beta-8CX, Beta-10CX ja Beta-12CX -koaksiaalielementeistä | AudioVideo.fi

Google translate usually makes only miserable gobbledigook trying to translate anything finnish, so I might also answer questions.

As I said, I've yet to hear the outcome in real life, but apparently they sound nice.

Regarding those dips in the treble response, the BMS I mentioned is probably the cleanest driver I've ever measured in that respect. Noticeably cleaner than the Seas 6,5" coaxial. Only minor dips here and there, but they're quite shallow and narrow. Oh, and it's one of the few drivers I've encountered that measures actually better than the datasheet suggests.
 
We measured some 18 Sound coaxials, but I can't remember whether it was the 12CX800 or the 12NCX750, but nevertheless it had a more ragged response in the upper regions. Then again, I don't believe one can judge the sound of a driver based on the FR alone. Surprisingly ragged responses can still sound quite good.

I like the bigger Tannoys, but they're off limits for DIY purposes now. And I actually slightly prefer the BMS to the 15" Monitor Golds. Oh well, maybe this should be it's own thread, since the OP was about Beyma, not BMS...
 

Interesting they recommend aiming the drivers towards the ceiling up to 20 degrees.


The flooder approach is also very nice:

kaiutinrakennusohje-yksisilmaiset-veljekset-beta-8cx-ymparisateileva-2809.jpg



.
 

Attachments

  • kaiutinrakennusohje-yksisilmaiset-veljekset-beta-8cx-ymparisateileva-2809.jpg
    kaiutinrakennusohje-yksisilmaiset-veljekset-beta-8cx-ymparisateileva-2809.jpg
    23.2 KB · Views: 398
anyone here have a passive crossover suggestion for Beyma 12cx? IIRC the factory suggested "textbook" 4500Hz ->5000Hz 12dB per octave coil and cap values.

Eminence had a "3K5" network which seemed to xover around 2K8 - that may half-ways work - but might stress the little compression driver

a guy on Youtube is using 0.18mH/2.84uf on his Beyma 12cx - I'll give that a try - I don't want to fry the tweeter

Beyma's 12cx woofer is quite extended on axis

Qts on my units measured quite a bit higher than factory spec

pEi1tIg.jpg

sJJ9wtL.jpg

1yy1Y8f.jpg
 
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.