Page 1 of 2 12 LastLast
Results 1 to 15 of 27

Thread: Chinese Beryllium diaphragms

  1. #1
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,776

    Chinese Beryllium diaphragms

    The supplier of JBL's Be diaphragms, Brush-Wellman, did an analysis of allegedly beryllium cones and domes that were sourced from China.

    What do you think they discovered?

    Go to the first link in the link below, and read the report.

    http://www.berylliumproducts.com/Acoustics.aspx
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  2. #2
    RIP 2009
    Join Date
    Feb 2004
    Location
    Rohnert Park, CA
    Posts
    3,785
    Similar links at: www.electrofusionproducts.com (Look under "Acoustics".)

    John

  3. #3
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Quote Originally Posted by edgewound View Post
    The supplier of JBL's Be diaphragms, Brush-Wellman, did an analysis of allegedly beryllium cones and domes that were sourced from China.

    javascript:openNewWindow('documents/China_Be_Domes_Report.pdf')

    What do you think they discovered?
    They are fake?

    Made from Mao's melted-down cooking pots?

  4. #4
    Senior Member
    Join Date
    Apr 2003
    Location
    GTA, Ont.
    Posts
    5,109
    Thanks Edge for that tiny look-see into fake Beryllium domes .

    I also appreciate the link to a bonafide US based hitech company that does make SOTA "Be" domes. Very Interesting stuff . Maybe within a decade I'll be able to afford to retrofit Be diaphragms into all my SR stuff .



  5. #5
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    And those guys wore such good-lookin' suits, too....

  6. #6
    RIP 2009
    Join Date
    Feb 2004
    Location
    Rohnert Park, CA
    Posts
    3,785
    This posting at PwoSoundWeb quoting a JBL rep. says the JBL diaphragms are really titanium with just a beryllium coating - curiouser and curiouser... http://srforums.prosoundweb.com/inde...70/#msg_206609

    John

  7. #7
    RIP 2010 scott fitlin's Avatar
    Join Date
    Apr 2003
    Location
    Brooklyn NY
    Posts
    4,343
    Wow, so theres really no pure Be diaphragms out there, except maybe for TAD?

    Whats the story on the TAD phragms, or are they also composite materials?
    scottyj

  8. #8
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Engineering spec says diaphragm is 0.0016" Be foil:

    http://audioheritage.org/vbulletin/s...ad.php?t=14369

    I just spoke to JBL Pro tech support, who inquired of engineering.

    Answer: "The information is proprietary...."

  9. #9
    Senior Seņor boputnam's Avatar
    Join Date
    Apr 2003
    Location
    northern california
    Posts
    6,142
    Quote Originally Posted by edgewound View Post
    The supplier of JBL's Be diaphragms, Brush-Wellman, did an analysis of allegedly beryllium cones and domes that were sourced from China.
    B-W mines their Be at Spor Mountain, UT. Interesting place - tuffacous rocks produced from local calderas. I've been there many times, first back in 1977 during the start of my field geologist days...

    Quote Originally Posted by scott fitlin View Post
    Wow, so theres really no pure Be diaphragms out there, except maybe for TAD?
    Not exactly true...

    Quote Originally Posted by scott fitlin View Post
    Whats the story on the TAD phragms, or are they also composite materials?
    No. TAD deposits / fogs their Be onto a Cu substrate and then dissolves the Cu away leaving a pure Be diaphragm.
    bo

    "Indeed, not!!"

  10. #10
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,776
    Quote Originally Posted by Zilch View Post
    Engineering spec says diaphragm is 0.0016" Be foil:

    http://audioheritage.org/vbulletin/s...ad.php?t=14369

    I just spoke to JBL Pro tech support, who inquired of engineering.

    Answer: "The information is proprietary...."
    There are valid reasons why they are made the way they are.

    Performance is one of them. Safety is another one...and there are others, too.

    If you've had the opportunity to hear the Everest II, and speak with the designer, all doubts would be laid to rest.

    My point for starting this thread was to save frustration and cash for those with some hope of cheap Be diaphragms.

    Read the Brush-Wellman papers on working with this stuff and you'll learn why it can't be cheap.....it's pretty high metallurgical science.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  11. #11
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    Quote Originally Posted by edgewound View Post
    There are valid reasons why they are made the way they are.
    And that would be how, Edge?

    [Presuming you're at liberty to tell us.... ]

  12. #12
    RIP 2010 scott fitlin's Avatar
    Join Date
    Apr 2003
    Location
    Brooklyn NY
    Posts
    4,343
    Quote Originally Posted by boputnam View Post

    Not exactly true...

    No. TAD deposits / fogs their Be onto a Cu substrate and then dissolves the Cu away leaving a pure Be diaphragm.
    Thanks Bo.

    I was just asking, cause I didnt really know. I do know of the process you describe, they call it sputtering, and TAD made a big deal about how they do it, because when other companies began using Be, they said the others cold rolled it, rather than the vacuum deposit process.
    scottyj

  13. #13
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,776
    Quote Originally Posted by Zilch View Post
    And that would be how, Edge?

    [Presuming you're at liberty to tell us.... ]

    Quote Originally Posted by edgewound
    Performance is one of them. Safety is another one...and there are others, too.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  14. #14
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    No, no. How they are MADE, Edge!

    Titanium composite or pure Be foil?

  15. #15
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,776

    They

    Quote Originally Posted by Zilch View Post
    Be foil
    .
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Aftermarket Replacement Diaphragms
    By 4313B in forum Lansing Product DIY Forum
    Replies: 94
    Last Post: 12-17-2006, 11:51 PM
  2. Difference between JBL coated diaphragms
    By Niklas Nord in forum Lansing Product General Information
    Replies: 15
    Last Post: 07-26-2004, 01:25 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •