JBL goes BMS

RE: JBL goes BMS, posted on May 8, 2012 at 13:20:03
Don Reid Audiophile Posts: 890 Location: Rural NW Georgia Joined: February 2, 2001 Contributor Since: April 1, 2010	JBL certainly makes it sound like great news? Have you heard them yet? I dream of an America where a chicken can cross the road without having it's motives questioned.

BMS, posted on May 8, 2012 at 16:41:06

Kloss

While if JBL is outsourcing to BMS that is a bummer. Still I really enjoy the new 1.5in BMS coaxial and the 4592nd midrange.

http://www.usspeaker.com/bms%204595nd-1.htm

RE: JBL goes BMS, posted on May 8, 2012 at 22:51:28
b.l.zeebub Audiophile Posts: 9361 Location: 52deg 28'N,1deg56'W Joined: April 17, 2006	JBL has been using BMS compression drivers for years now in some of their models of PA speakers.

BMS (not), posted on May 9, 2012 at 00:26:12

djk
Manufacturer

Posts: 6135
Joined: June 17, 2000

The new JBL D2430K is very, very different than the BMS co-axial drivers.

Alex Voishvillo worked for Cerwin Vega for 7 years before joining JBL and worked for Popov R&D Institute for Radio and Acoustics in Russia for 18 years.

If someone has $20 to spare:

"Audio Engineering Society Convention Paper" Dual Diaphragm Compression Drivers, "Author Alex Voishvillo, Preprint 8502, presented at the 131st Convention, New York, Oct 2011"

Has response graphs, etc.

http://images3.freshpatents.com/pdf/US20110085692A1.pdf

RE: JBL goes BMS, posted on May 9, 2012 at 01:25:34
el`Ol Audiophile Posts: 137 Location: Bavarian Forest Joined: May 1, 2006	Seems that the JBL people have found a way around the BMS patent by using two identical diaphragms. That they have used original BMS drivers before is new to me.

RE: BMS (not), posted on May 9, 2012 at 07:53:15
Kloss	Thanks for the link. Wonder what the new JBL D2430K will retail for?

RE: JBL goes BMS, posted on May 10, 2012 at 03:55:54

b.l.zeebub
Audiophile

Posts: 9361
Location: 52deg 28'N,1deg56'W
Joined: April 17, 2006

Apparently JBL 2407s start their life as BMS 4540s (hope I got the numbers right).
They are used in EONs and the smaller arrays. These are the compression drivers JBL does NOT offer replacement diaphragms for.

On the Audioheritage site forum (a site for everything relating to Lansing, Altec and JBL) someone said that the new co-axial JBL drivers on the inside look very much like BMS co-axials. AFAIK the annular polymer diaphragm is a BMS invention.
As is usual for badge-engineered items JBL says nothing while BMS just states that they produce drivers for other speaker and driver manufacturers but they are not naming names.
It was the same for my Tannoy-badged MC2 Audio amp, even when I was talking to Ian McCarthy (co-founder of MC2 and previously E.A.R.) on the phone I had to ask him directly if they could service it before he admitted that it was one of theirs.

RE: JBL goes BMS, posted on May 10, 2012 at 10:28:19

jasonwinslow@yahoo.com
Audiophile

Posts: 111
Location: North Carolina
Joined: July 7, 2005

The 2406 and 2407s are BMS drivers...that has been common knowledge for a long long time. The JBL labeled drivers are more expensive than the BMS labeled drivers. At one time you could get the 2407s on eBay for $50-60 bucks each, if not cheaper. The 2407s were used in the Vertex array systems.

JBL changed the 2408s which are quite similar to the 2407s in essence, but cost cutting changed details. The 2408h-1 is a completely different design than the 2408h.

Errata, posted on May 11, 2012 at 03:48:42

djk
Manufacturer

Posts: 6135
Joined: June 17, 2000

"These are the compression drivers JBL does NOT offer replacement diaphragms for."

Are you sure (see link), it's the 2414 that is FSO (factory service only).

"the new co-axial JBL drivers on the inside look very much like BMS co-axials. "

What model number is this new JBL co-ax?

The D2430K is a dual diaphragm driver with two 3" VC that are wired in parallel, no crossover. Nothing like a BMS with its 3.5" and 1.75" and a crossover.

"AFAIK the annular polymer diaphragm is a BMS invention."

Olson showed a diagram of a BMS-type compression driver with a resin-impregnated diaphragm in the 1940 edition of Elements of acoustical engineering.

http://www.jacksmusicfactory.com/default.asp?productid=90399

RE: Errata, posted on May 11, 2012 at 06:26:36

b.l.zeebub
Audiophile

Posts: 9361
Location: 52deg 28'N,1deg56'W
Joined: April 17, 2006

http://www.audioheritage.org/vbulletin/archive/index.php/t-32425.html

The (apparently erroneous) info that JBL does not supply replacement diaphragms for the re-badged BMS drivers came from the site of some US dealer whose name I don't remember.
May be they were just trying to sell more drivers than spares, who knows?

Doesn't make much difference to me as I neither use JBL nor live in North America.

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JBL goes BMS

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