The BMS group buy thread!!! - Page 16

So it's safe to assume this will be the last BMS group buy?

Evaaaar. I have some 4550's for sale for $1,000,000 each.

I hope not. BMS drivers are excellent. I look forward to testing them more thoroughly vs the DE250 and DNA360's that I have. There are certainly differences in technology between the BMS and more conventional CDs like the B&C and Denovos. Whether that translates into advantages for HT and hifi applications remains to be seen.

Jack, thanks for the pics. Those are some of the best cutaways of BMS coax drivers that I have seen. Do you happen to know if the JBL D2430K (aka the the JBL D2 in the new M2...also in the VTX arrays) is a BMS sourced driver? It is a dual diaphragm annular coax and I know JBL has rebranded BMS drivers in the past.

No, this is the first group buy.

Just a couple of kinks to work out.

Good to hear!

Thanks. I am guessing its also the only one you have seen. It's quite rough as I just ran it through the table saw.
It was for a trade show, and is a good visual that people can hold in their hands.

I have no new information on the D2. It has been over a year since I last talked with BMS in person at the Pro Light and Sound.

I've seen some cutaway drawings but I haven't seen an actual 3D cut like that.

After posting about the D2 I did some searching and found that it is not related to BMS...at least not directly. It uses 2 diaphragms in a sort of push-pull and doesn't seem to require a crossover. It appears to be an advancement on the BMS tech to be honest. I heard JBL lists them at $2k per driver and that you can't actually buy them.

I've been following along, merely for informational purposes.

I defer to you in all things CD, but push-pull isn't correct as I understand it..and I may be wrong.

I believe it's more to the tune of a co-entrant, dual driver scenario. Not unlike a mini dual opposed IB manifold, whereby the energy pushes in phase towards each other then is routed out the exit. I immediately think of it this way ... because I also describe/think of my quad, dual opposed IB manifold as not unlike a compression driver system when someone inquires.

But the D2, the twin, it's said the anular drives lower moving mass, yet maintain overall radiating area as their typical CD approach. Thus, increased power handling, etc, and supposedly better HF characteristics (smoothness, extension, distortion, blah blah). It would be interesting to determine the genesis of the JBL team pursuing this approach.


I'll stop, and continue following along, it's been interesting for sure.
Best of luck to all involved.

You are right FOH. I don't think I had been looking at this driver the right way at all. I think I had wanted to view it as a modification of the BMS design when the only real similarity is the use of two annular diaphragms. Instead they are using two smaller, but equal sized diaphragms playing the same range in close proximity. It is actually more similar to a Danley paraline, but in miniature. It is quite an amazing design in fact. I'd like to see them shoot for a different range to be honest and use larger diaphragms. Extension to 40khz is nice to spec sheets but pretty meaningless. I'd rather see extension to 18khz AND the ability to play as low as 400hz without using a metal diaphragm OR a coaxial like the BMS. I could see that as being the next step for JBL. They could probably ditch the mid horns on their ScreenArray's with the exceptional power handling afforded by the dual VCs.

Here is the article that does the best job explaining: http://www.prosoundweb.com/article/designer_notebook_an_in-depth_look_at_the_new_jbl_vtx_series_line_array/P2/

"As seen in Figure 1, two diaphragms (3 and 6) are vibrating in “push-push” mode, and are loaded by their corresponding phasing plugs (4 and 5)."

Sorry about the OT.

Diaphragm, BMS related,co-use of and exit JBL. And no crossover because they are running the same bandwidth through both diaphragms.

I have seen other references recently on the internets that describe it as you do, but not in as good of detail.

Well now I have, figure 3.

It is an amazing design. It's exciting seeing what's achievable in these SOTA designs from BMS, JBL, etc.

You're right, it would be fascinating to see them implement this tech in the top side of a two way. The annular component of the design limiting break-up and controlling motion quite well, but the engineering only starts there...and the manner the acoustic energy in handled is interesting. Also, regarding how the VTX' three D2 drivers output coalesces, is really something. I'd seen the add copy, but not payed close attention. However the care taken in path length integrity and summation after leaving the driver throat, and prior to summing at the waveguide baffle face, is pretty cool. There's a hell of a lot of tech loaded in that VTX cab.

I've said it before, but concert goers these days have little idea about the amazing technology involved in every facet of a high quality live production. There's some phenomenally high quality audio out there .. but like all things audio, it's about the room. That said, if you've got a seat in the front third of the house, or a decent place equidistant L-to-R at an outdoor venue, you could experience some superb sound.

A lot of amazing gear out there.


Thank you sir. I do enjoy my compression sub system

Agree...looks like the VTX-V25 uses three of the 3" coil/1.5" exit version. Oh to get my hands on three of those drivers!

Well, all you have to do is buy a VTX line array cabinet.

~$13k and they're yours. Surely you could part it out and use the pair of neodym/diff drive 15s, the quad set of neo/diff drive 8s, along with the electronics and even salvage a little multi-ply Russian birch! Who says you can't get those D2 drivers, huh...?

You could reverse engineer something in that box and implement it in the Octagon. Or better yet; JBL could reverse engineer your Octagon, and employ some of your approaches. Yep, true story.

Anyone know what 1" CD the JTR Noesis 228 uses? I read the big noesis uses BMS coax CD. Based on some reviews the 228 noesis did pretty well vs the 212 for movies.

I haven't seen anything you might try searching the BMS forum. That is where I was able to find a pic toidentify which coax model was being used.

OK just found a pic on the JTR forum and it looks like a 4547nd with an XR1064 horn. Any idea what the exit angle is on the 4547nd? It's a fairly new CD so not much info out there. I'm curious if it will work well with a SEOS.

What is the exit angle on the XR1064?

The XR1064 is an 18Sound horn with a proprietary profile. I've not seen them publish any specs regarding entry angle. Unless they use some sort of a catenary that attempts to match a specific exit angle it likely doesn't have a specific entry angle. It is likely engineered to work with some specific 18Sound driver.

Do you know the exit angle of the 4547nd?

The 4547 is 26.3 degrees, and the 4545 is 16 deg.
Also, the crossover points seem to be wrong on the BMS site.
Like the 4552, the 4547 can be crossed to 1Khz.

Regards, Jack

The 4550 remains the best BMS driver to use with the SEOS12/15/18 horns then. You could use the 4545 but it would require adapter. I would not use a threaded adapter unless you have no other alternative.

Edit: Yes, all CD manufacturers are conservative as to how low their CDs can play. Of course they are more concerned about the pro guys who will be pushing these drivers to the limits of excursion. In a home setting you could run most of these drivers with a 500hz 12db cross and never damage them.
Edited by coctostan - 4/13/13 at 12:11pm

coctostan, you have (a long winded) pm. Thanks.

- Nate

Erich, when will these drivers begin shipping out to the participants in the group buy? How are the shipping costs to be handled?

At least 2 of the higher end 18 sound 1” CDs (NSD1095N & ND1090, no info on others) have an exit angle of 27 deg so it’s probably no coincidence that the 4547nd with an exit angle of 26.3 deg was used with the XR1064 in the 228 noesis.

Jack, do you know the exit angles of the 4593nd and 4594nd?

Erich,
I sent you a PM regarding the shipping of these BMS products to the buyers.

Erich,

I know it's your busy time of the year.... but can you give an overall update of where we are with the BMS group buy shipments, the Poland pallet shipments, and how it all flows in with regular DIY Sound Group orders? Are you 1 week behind clearing just regular DIY sound group orders? 2 weeks? more?

Have you found a box solution for the BMS stuff that came volume packed? Is everything in your possession now (crossovers coming from Jack direct based on what I see posted in this thread to go with stuff that came from Germany)?

When should we expect the BMS and Poland stuff to start shipping?

Thank you.

Got my 4550s today. Thanks Jack and Erich!

They are hefty suckers. Well built, beautiful, sexy looking CDs. Looking forward to any crossover designs that get built around them. I'm definitely interested in trying these out.