Flat compression drivers

[holger honda]

Im looking for some input on compression drivers.
It will be mounted in a emenence beta 10cx (coax)
Id like a unit with a flat freq response and a neutral sound.
I have heard good things about the B&C dt25.
Any other candidates?

[ScottG]

Flat freq. response is product of driver and horn.

(note that the freq. response of the driver here is elevated as freq.s decrease because of the horn used..)

BMS 4540ND

I doubt there is a better compresion driver in this freq. range (including offerings from more expensive sources like TAD and ALE). Structurally the design is quite different than others, and then there is the gauss of the magnet which is awesome.

http://www.assistanceaudio.com/02_bms.html

http://www.woodhorn.com/prices.htm

The dealer for woodhorn says that this is the best of all the BMS drivers.

[simon5]

You could also look at the Adire Audio ACD1 Mark II.

Frequency response is flat up to 20 kHz and the FR curves they give on the website is when mounted on a Eminence Beta 10CX.

You need to design the crossover well because the short horn on the 10CX create a hump in the lower end.

[Brett]

Lots of the phenolic beymas are very good too like the CP380M, but I bet the BMS is easier to get. I'm rather fond of my 4590's.

[holger honda]

Scott,thank you for link and advice.
the acd1 is what im replacing,due to it not being able to handle the power im feeding it.
This is the best uve ssen so far,and I can deal with the price.

[dooper]

Chico CA Land of the fooled

Now known as the pyrite state?

dooper

[Variac]

Very exciting, Scott. At a very reasonable price!!

You like this coax driver? Sure has the bells and whistles!
Looks cool and prob lightweight also.
Know anything about it?

http://www.assistanceaudio.com/15_Assaudcoaxial.html

[ScottG]

Originally posted by Variac
Very exciting, Scott. At a very reasonable price!!

You like this coax driver? Sure has the bells and whistles!
Looks cool and prob lightweight also.
Know anything about it?

http://www.assistanceaudio.com/15_Assaudcoaxial.html

Thats a new one to me. But Ciare does make good OEM drivers, and neo magnet drivers tend to sound better than ceramic magnet drivers for a given gauss. (btw, I'm guessing the response is 1/24 octave smoothing so the graph looks "worse" than what it might otherwise look like with 1/3 smoothing..)

What I don't like is the gauss of the driver (at only 1.15), this is hardly better than an average ceramic magnet. The driver's mass is good (for its fs) but is still relativly average considering the nearly non-existant dustcap, (ex. - extraordinary can be found from Supravox). Finally there is no baffle step "bump" included. Meaning you'll either have a bass driver working up to this region (see below) or you'll have to rearhorn load the driver. (and then there is the cost that seems exhorbitant..)

On the other hand I don't see the need for this driver. Considering the baffle step problem (unless you rearhorn load it), you'll need to purchase a bass driver (actually bass-to-mid). With that in mind you should look for a mid driver and then crossover to a bass driver (typically with only a lowpass on the bass driver). Though I've never heard it, my suggestion for such a mid co-axial driver would be:

McCauley C326CX (with the dust cap removed);

Alternativly find a bass (mid-bass in this case) driver that extends higher (in freq.) and then do what Brett does - use the BMS compression coaxial (but instead use the neo version: 4592ND). For the mid-bass I rather like the specs and the graph on the 12.64NdW1 OEM Ciare (Assistance Audio) - when considering the cost. It would be better though if two of these could be purchased (and used per side) with 16ohm VC's (parrallel to 8 ohms). Use a 1st order low pass on them at around 400 Hz and expect a crossover (summed point) around 800 Hz.

[Variac]

So you think $280 for the woofer and horn driver together is high?


Here are some BMS coax's one with neo at $364:

http://www.assistanceaudio.com/17_BMSC%26C.html

they have a nice long horn for the compression driver, BUT that might create some resonances since it is in front of the woofer cone.
Not a lot of info on these that I could find, maybe the BMS website.
One model is neo. I guess no particular reason to go with BMS woofers unless the coax bass driver is designed to work well with their horn driver...

[ScottG]

To high, no - but not as good a value as the McCauley I mentioned with the BMS 4540ND. Essentially they are charging aprox. 150 US for the 12 inch coax.

As for the 15 inch coax from BMS - I think its kinda lame. Dispersion will be pathetic (on the horn) and you'll have early reflections (and resonances) from the horn/driver combo. To a substantial degree the early reflections and resonances can be reduced with a silicon borscilate paint on the outer profile of the horn, but you'll still have a dispersion patter around 60 degrees (guess). If its up to 90 degrees or more then it might not be so lame..