BMS 2" Neodymium Coaxial Compression Drivers - Any Experiences?
Rick M
(http://www.bmselektronik.de/products/h_driver_4594ND_e.html)
Does anyone have any experience with these drivers, or CODA systems
using
these drivers?
http://www.bmselektronik.de/products/h_driver_4594ND_e.html
I'm currently designing some full range (3-way) trap boxes which are
something of a redesigned EAW KF850EF, but with (2) 15" drivers,
1 10" driver, and a 1.4" HF compression driver on a medium format CD
horn.
After hearing about this driver however, I'm considering a redesign
of the trap boxes in order to possibly accomodate a large format CD horn
suitable for use with these drivers.
Any input on these drivers would be appreciated.
-Rick
liquidator
"Rick M" <dis...@ptd.net> wrote in message news:3D46206D...@ptd.net...
Ping Carl Updegraff I think he uses them...
Be aware- in a live situation the simplest solution often works.. the more
complicated you make your cabs the less likely they will work...at least
well in most apps...
Shaun
> I'm curious about these BMS's H4594-ND 2" coaxial compression drivers.
> (http://www.bmselektronik.de/products/h_driver_4594ND_e.html)
The 4594's aren't available yet. I am currently demoing a BMS 4590 in one
of my EAW cab's, A/B'ing with TAD 4002. The BMS is a very nice sounding
driver, no doubt, and I am convinced enough to upgrade. I'm waiting for my
4594's before I convert my rig over.
At first, the TAD 4002 seemed to be more efficient, and sounded better in
the mids, as they are probably the best sounding 2" driver available. The
BMS are certainly capable of being more hi-fi, and had a flatter response,
especially up high. Overall, I think the TAD sounded more "normal" than the
BMS, when using its passive crossover...by normal, I mean it was what we are
used to hearing a 2" driver sound like in a PA application.
The VHF in the BMS has the higher extension of good 1" drivers, which was
immediately evident, but there was a gap or dip in its response at the
crossover, and it seems to skew phase a bit. Putting it thru FFT analysis
confirmed this, but it wasn't as radical as my ears first thought. When I
biamped the driver HMF+VHF sections directly, WOW!
The rolloffs are steep: although it can go VERY low, the HMF has a hard
time above 5.4k, and the VHF doesn't like to go much below 8k without
assistance, but I came up with some DSP settings to make it shine. The
recommended 6.3k crossover point is basically non-negotiable, without a bit
of DSP magic. Getting all the phase responses correct took the most time.
It's nice to have the extra margin of control that a 5-way system offers,
and I should gain many dB of headroom, and have higher HF extension.
I thought it might be possible to run the HMF up high enough to cover up a
blown VHF section in an emergency, but no. In my system, I can move the
crossover points to cover either the LF, LMF, or HMF sections if they went
out, but the VHF is on its own. The BMS website doesn't offer very detailed
spec's for the VHF, but it seems to have the same sensitivity as its HMF
component; my amp gains on both sections are equal.
I was thinking about using a Crest 3301/7001 pair in each rack, with one
driver per channel at 8 ohms. I'm currently running a Crest 4801 for HF,
one TAD 4002 per channel at 16 ohms for quieter shows, and bridged into 8
for rock/metal. Using the 4801 for biamping the BMS lets me run each
section at 4 ohms per channel on one amp, so I'm torn between my first idea,
and using a 3301 stereo for VHF, and running the 4801 bridged into 4 for
HMF.
--
Shaun Wexler,
Hellsgate Sound
http://www.hellsgate-sound.com
sh...@hellsgate-sound.com
Carl Updegraff
In one of my custom passive X-overs for the 4590, I had asymmetric
points.
The LPF was at 5.5khz, and the HPF was at 7.2Khz. This seemed to work
well, and didn't exhibit the phasing anomalies you were mentioning. It
also eliminated the 6khz (ish) peak that is evident w/ the stock
x-over.
Over all, the factory passive is as good as a basic x-over can be. It
can certainly benefit some tweaking, though.
Try running the MHF w/o LPF leg.
I've had two VHF blow on me recently, and w/ my current passive x-over
NOT having a HF roll off on the 2", I still managed to get useable
8khz out of it.
Regardless, the BMS 4590 AND 4594 drivers are the VERY BEST
compression drivers available, at ANY COST.
Amazingly enough, it cost me less to import them than it did to buy
new JBL 2" drivers domestically.
Jack Arnott or Jay Peabody is the guy to talk to (depending on region)
about getting some.
Carl
Rick M
>
> On 7/29/02 10:12 PM, Rick M wrote:
>
> > I'm curious about these BMS's H4594-ND 2" coaxial compression drivers.
> > (http://www.bmselektronik.de/products/h_driver_4594ND_e.html)
>
> The 4594's aren't available yet. I am currently demoing a BMS 4590 in one
> of my EAW cab's, A/B'ing with TAD 4002. The BMS is a very nice sounding
> driver, no doubt, and I am convinced enough to upgrade. I'm waiting for my
> 4594's before I convert my rig over.
What I was wondering with these drivers is their potential in line array
applications. Near perfect phase coherence in the MF/VHF bandpasses.
The only drawback I can see is how to get two horn/driver assemblies
into a 14" high line array element form factor (like McCauley's MLA5s.
:) While I supposed it could be done, I suspect one would have to
compromise the lower f response of the MF portion of the driver with a
compromised dual horn/waveguide. I don't really see that being a major
tradeoff however, as I'm still a bit skeptical about
it's 200-22KHz f_range spec, and pretty much figured a more practical MF
x-over somewhere between 350-800Hz anyway.
> At first, the TAD 4002 seemed to be more efficient, and sounded better in
> the mids, as they are probably the best sounding 2" driver available. The
> BMS are certainly capable of being more hi-fi, and had a flatter response,
> especially up high. Overall, I think the TAD sounded more "normal" than the
> BMS, when using its passive crossover...by normal, I mean it was what we are
> used to hearing a 2" driver sound like in a PA application.
>
> The VHF in the BMS has the higher extension of good 1" drivers, which was
> immediately evident, but there was a gap or dip in its response at the
> crossover, and it seems to skew phase a bit. Putting it thru FFT analysis
> confirmed this, but it wasn't as radical as my ears first thought. When I
> biamped the driver HMF+VHF sections directly, WOW!
This is exactly what I'm interested in hearing about. So MF/VHF phase
coherency is slightly off with it's crossover? I would imagine biamping
would improve this, but am I to assume (by your "WOW!") that by
biamping, phasing is as near perfect as they tout the time alignment as
being?
> The rolloffs are steep: although it can go VERY low, the HMF has a hard
> time above 5.4k, and the VHF doesn't like to go much below 8k without
> assistance, but I came up with some DSP settings to make it shine. The
> recommended 6.3k crossover point is basically non-negotiable, without a bit
> of DSP magic. Getting all the phase responses correct took the most time.
> It's nice to have the extra margin of control that a 5-way system offers,
> and I should gain many dB of headroom, and have higher HF extension.
>
> I thought it might be possible to run the HMF up high enough to cover up a
> blown VHF section in an emergency, but no. In my system, I can move the
> crossover points to cover either the LF, LMF, or HMF sections if they went
> out, but the VHF is on its own. The BMS website doesn't offer very detailed
> spec's for the VHF, but it seems to have the same sensitivity as its HMF
> component; my amp gains on both sections are equal.
I know. :( The only VHF data available seems to be a response
curve/graph of Coda Audio R36 speaker (which uses the 4590) available in
their pdf downloads. The jpeg image of the R36 shows a small format
(aprox 14" x 7"?) CD horn. Dispersion is listed at 90x60 degrees, and
the crossover used is 700 due to the format of the CD horn being used.
This also seems to confirm my notion of a higher MF crossover as being
more practical.
> I was thinking about using a Crest 3301/7001 pair in each rack, with one
> driver per channel at 8 ohms. I'm currently running a Crest 4801 for HF,
> one TAD 4002 per channel at 16 ohms for quieter shows, and bridged into 8
> for rock/metal. Using the 4801 for biamping the BMS lets me run each
> section at 4 ohms per channel on one amp, so I'm torn between my first idea,
> and using a 3301 stereo for VHF, and running the 4801 bridged into 4 for
> HMF.
What I'm wondering is if it's possible to design a line array element
with dual 15" LF drivers, a usable 500Hz MF crossover (and thereby
eliminate MF _cones_), AND find a suitable CD horn with dimensions
allowing a 2 horns to be stacked into an element form factor that
doesn't exceed 14" in height. Volumetrically loading the 15" allows
this, but the MF/VHF horn required for a usable 500 MHz crossover might
prove more difficult to do if one wants to maintain a 1:1 LF/MF-VHF
driver ratio that will also fit into this form factor.
-Rick
Phildo
"Shaun" <see.sign...@email.address> wrote in message
news:B96BFB55.A600%see.sign...@email.address...
> I thought it might be possible to run the HMF up high enough to cover
up a
> blown VHF section in an emergency, but no. In my system, I can move
the
> crossover points to cover either the LF, LMF, or HMF sections if they
went
> out, but the VHF is on its own. The BMS website doesn't offer very
detailed
> spec's for the VHF, but it seems to have the same sensitivity as its
HMF
> component; my amp gains on both sections are equal.
Wow, you can hear VHF? I wish I could. Would be very useful for sorting
out problems with radio mics :-)
Phildo
Shaun
> I'm still a bit skeptical about it's 200-22KHz f_range spec, and pretty much
> figured a more practical MF x-over somewhere between 350-800Hz anyway.
Nope, it's accurate. Not sure how much power it would take using it that
low, but they seem pretty tough. I haven't had a chance to really pour the
coals to it, yet, but I'll give it a REAL workout soon, to see how it sounds
when pushed fairly hard.
> This is exactly what I'm interested in hearing about. So MF/VHF phase
> coherency is slightly off with it's crossover? I would imagine biamping would
> improve this, but am I to assume (by your "WOW!") that by biamping, phasing is
> as near perfect as they tout the time alignment as being?
The passive crossover exhibits phase shift, and the two driver sections are
not perfectly aligned, either. I had to use a 0.045 ms delay; about 1/2".
> I know. :( The only VHF data available seems to be a response
> curve/graph of Coda Audio R36 speaker (which uses the 4590) available in
> their pdf downloads. The jpeg image of the R36 shows a small format
> (aprox 14" x 7"?) CD horn. Dispersion is listed at 90x60 degrees, and
> the crossover used is 700 due to the format of the CD horn being used.
> This also seems to confirm my notion of a higher MF crossover as being
> more practical.
I'm getting an extremely flat response on a 22"x24" CD horn, and it goes as
low as I want it, though I prefer the timbre of paper cones up to 640-800.
I got the best sound crossing out of my 2x10's at around 900 Hz, but it also
sounded nearly as good way down into the 400's.
Mike Diack
<see.sign...@email.address> wrote:
<<lots of useful stuff about the BMS driver>>
How would these things compare in an A/B shootout against, say, a 244x
+ ring (or slot). What is the spares situation like (diaphragms
available and field replacable ?) and most importantly how much do
they cost (drivers & diaphragms) ?.
cheers
M
Shaun
> how much do they cost (drivers & diaphragms)?
Very affordable. A BMS 4594 costs about the same as my TAD 4002, that's 3
times as much as a 4590, which itself costs a bit below par for a 2" driver.
Rick M
Heh... the first time I heard the term 'VHF' applied to the audible
spectrum, it sounded kind of wierd. Especially being a TV/Satellite
guy.
-Rick