# Beyma CP380M - any experience with this driver?



## mdrake (Jan 31, 2008)

I lost one of my selenium t compression horn drivers and need to find a replacement. I really did not want to spend what they are asking for the Beyma CP380M but if the driver is worth it, then I will. Does any one have experience with compression drivers? I tired a Vifa soft dome and that lasted two weeks before she let go. The Vifa did not have nearly the dynamics as the selenium ti. :R I am open to other suggestions besides compression drivers if they will perform comparably or at least close. 

Matt


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## mdrake (Jan 31, 2008)

I guess some clarification is in order.  I am working on a speaker similar in design to the emerald physics CS2. I have the Eminence 15's and the DCX2496 but I am missing the compression driver. 

I am also having staging issues do the the close proximity of the side and rear walls. The baffles are mounted only 8 inches away from the wall. Any ideas on creating a stage with speakers in close proximity to the wall? I have added a substantial amount of toe in which seems to help considerably. 

I think I might have located the compression driver. I found a BMS 4540ND compression driver for 70.00 which seems to fit my budget nicely. http://www.assistanceaudio.com/02_bms.html#cost

P.S. Warning after watching Sherlock Holmes one has a tendency to use large words. :dumbcrazy:

Matt


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## Lucky7! (Jan 7, 2008)

It's an excellent driver. I've used them at home and have a set loaned out, it seems permanently.

There was a build by a member on another forum using these on the QSC 152 WG and a TD15M. I've heard them and thought they sounded excellent.

BMS drivers are very good (I really like my 4590 but have no application for them ATM), the B&C DE250 (used in Geddes Summa) I have used (they're going in my surrounds) and the 18Sound ND1090 (first Ti driver I like) are worth looking at.


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## mdrake (Jan 31, 2008)

*Re: Beyma CP380M or BMS 4552ND to build a 2-way speaker*

Thanks, that was VERY helpful! Any ideas on how to get a hold of the QSC waveguides? 
Do you think I can order directly from QSC? 

Seems the QSC waveguide is able to work well at 1k, which allows me to follow the golden rule of 1 octave up from minimum freq. for the BMS 4552ND. This should help limit beaming from the 15. 

The BMS is half the cost of the Bemya, do you really think the Bemya is worth extra money? 

Matt


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## Lucky7! (Jan 7, 2008)

*Re: Beyma CP380M or BMS 4552ND to build a 2-way speaker*



mdrake said:


> Thanks, that was VERY helpful! Any ideas on how to get a hold of the QSC waveguides?


Glad to help. I've had quite a few horns, WG's and CD's over the years.


mdrake said:


> Do you think I can order directly from QSC?


Yep.
Round 122i and rectangular 152i. Brandon did some measurements on some WGs and CD's; the QSC 044 is the 152i and the Pyle is the JBL Ewave WG and is also used in the Audiokinesis Rhythm Prism's (Celestion 1731 as CD)



mdrake said:


> Seems the QSC waveguide is able to work well at 1k, which allows me to follow the golden rule of 1 octave up from minimum freq. for the BMS 4552ND. This should help limit beaming from the 15.


Wayne Parnham of Pi speakers has an excellent article on DI matching of speakers here. The big question is more like which 15 will do 1k _well_. The TD15M will, and so apparently will the JBL 2226, though I have never used them that high. Wayne does in his designs.

Here is one of Doug's TD12M/152 WG threads, with a link to the build thread in the first post.
Brandon's No Quarter 
thread.

There are a couple of others at AVS, but it's hanging for me ATM and can't get the URL's. Got guests soon, so I'll try again in the morning.


mdrake said:


> The BMS is half the cost of the Bemya, do you really think the Bemya is worth extra money?
> 
> Matt


That's a tough call on SQ as I haven't used the BMS. However quite a few other DIYers have and it's getting good raps, so my gut says go with it especially with the savings.


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## Lucky7! (Jan 7, 2008)

Here is Dave's thread, as mentioned in post 3.


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## mdrake (Jan 31, 2008)

Thanks and THANKS!!! I think I will give the BMS a try. Those links are really helpful. :T

Matt


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## Lucky7! (Jan 7, 2008)

My pleasure. 
Let us know what WG you get and measurements will add to the general database.


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## Lucky7! (Jan 7, 2008)

Forgot a couple of others that might prove interesting reading.
Opinion's on econowave speakers or other suggestions for mains??
Flex Your PCD Mettle
Huge-mungeous Ewave thread
 AE TD15X + B&C DE500 + QSC Waveguide questions & build thread 
Factors Affecting Sonic Quality of Mid & HF Horns & Waveguides  - this one has been occupying my thoughts a bit recently and some testing is forthcoming WRT mouth termination and my Unity's once I work some bugs out of the new measuring system and build a new mic preamp.
DIY Axially symmetric oblate spheroid CD waveguides, in solid Oak One of my 'inspiration' builds
Horn / Waveguide Contour Comparisons

I expect a two thousand word synopsis on my desk no later than 9am Friday.


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## mdrake (Jan 31, 2008)

AWESOME! Thanks! 
What mic and software are you using for measuring? 



> I expect a two thousand word synopsis on my desk no later than 9am Friday.


 Funny  Although I feel like I could write one with all this research. lol 

I have a feeling the crossover slopes are going to get interesting when I try to match the waveguide/driver to the 15....


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## Lucky7! (Jan 7, 2008)

mdrake said:


> AWESOME! Thanks!


No worries. As I find more, I'll keep adding them, not to overload but maybe to compile into a bit of a High Eff / Waveguide 'wisdom' thread.


mdrake said:


> What mic and software are you using for measuring?


I have an IBK Akustik EMM8 calibrated, same as Illka used for the sub tests. I used to have a neato self designed AD797 based preamp for it but now have to build another (don't ask, I'll start swearing). Also have an ECM8000 and access to some Earthworks mics. Forgot to add, I want to get an ACH01 accelerometer soon to be able to do panel vibration measurements. 

It also occurred to me the other day, that rather than trying to hump all my measuring kit to a field to get some good half space measurements, I have a possibility at home. On the second floor of my apartment (3 stories up, maybe 12m) I have a balcony. If I were to build a stand to get the speakers above the brick railing so they face out, away from my building, and add a stand to support a mic in front of them in the correct position, then (I think) I can do impulse measurements to quite low frequencies.

I'm learning Soundeasy and HOLMImpulse. 



mdrake said:


> Funny  Although I feel like I could write one with all this research. lol


That was my thought when I posted them.



mdrake said:


> I have a feeling the crossover slopes are going to get interesting when I try to match the waveguide/driver to the 15....


Wayne Parnham has a bit of a post here about DI matching and a few others I'll add later as remember where they are.


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## mdrake (Jan 31, 2008)

> No worries. As I find more, I'll keep adding them, not to overload but maybe to compile into a bit of a High Eff / Waveguide 'wisdom' thread.


Great idea :T

Sound Easy is the software I was leaning towards but some report that the GUI is hard to use. So, I have been waiting. Which do you like better? 

That balcony might work just be careful. I would hate to drop an expensive mic from two floors up.  

Matt


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## mdrake (Jan 31, 2008)

*Re: Beyma CP380M or B&C*

Does anyone know if you can remove the back of a B&C DE12 and use it dipole? 

Matt


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## horn-academy (Jul 1, 2010)

mdrake said:


> I lost one of my selenium t compression horn drivers and need to find a replacement. I really did not want to spend what they are asking for the Beyma CP380M but if the driver is worth it, then I will. Does any one have experience with compression drivers? I tired a Vifa soft dome and that lasted two weeks before she let go. The Vifa did not have nearly the dynamics as the selenium ti. :R I am open to other suggestions besides compression drivers if they will perform comparably or at least close.
> 
> Matt


Hello, i used many times a pairs of cp380m compression drivers , very impresive speaker coupling with Iwata horns.
Great sound.
Phil


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