Results 1 to 11 of 11

Thread: noise from my JBL L300'd mid

  1. #1
    Junior Member
    Join Date
    Jul 2010
    Location
    NA
    Posts
    19

    noise from my JBL L300'd mid

    I just brought back my JBL L300 from almost 2 years in restore .
    I connect and everything sound good but one of the compression driver (LE83) sound "cracky" at some freq .
    It's not clear for me what is the correct impandance of the (8 or 16)?
    In this link :
    http://reconingspeakers.com/products...5-diaphragm-2/

    It's seems i need 16ohm but i can see other saying 8ohm ....so a bit confusing.

    I don't have any intention buying original diaphragms at 360$ (orange county ),
    But from the other hand i don't want low quality replacments for 30$ each.

    Heard Radian has high quality diaphragms that can sound as best as the original JBL,
    can some one approve it?
    Is it complex to replace it by myself?

    Thanks!


  2. #2
    Senior Member hatrack71's Avatar
    Join Date
    Feb 2008
    Location
    Helena, Mt.
    Posts
    203
    The radian diaphragms are good for the $$. Make sure you get two- so each side sounds the same. They are very easy to replace if that is what the problem is. You may want to get a full set of the red wax seals if you are doing a 100% anal resto. The other possibility could be a failing capacitor in the crossover or possibly the polarity is wrong on the diaphragm. Have you swapped the driver to the other L300 to confirm? Have you checked the polarity on the driver in question?

  3. #3
    Senior Member BMWCCA's Avatar
    Join Date
    Feb 2006
    Location
    Virginia
    Posts
    6,964
    Did you check the L-pads?

    Two-years of sitting around can cause them to be a little touchy. Try running them through their full sweep a few times . . . with the system off, just in case. I didn't see any mention of the extent of your restoration is why I mention this. If the L-pads have been replaced already, just ignore me.
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

  4. #4
    Senior Member ivica's Avatar
    Join Date
    Jan 2008
    Location
    serbia
    Posts
    1,633
    Quote Originally Posted by hatrack71 View Post
    The radian diaphragms are good for the $$. Make sure you get two- so each side sounds the same. They are very easy to replace if that is what the problem is. You may want to get a full set of the red wax seals if you are doing a 100% anal resto. The other possibility could be a failing capacitor in the crossover or possibly the polarity is wrong on the diaphragm. Have you swapped the driver to the other L300 to confirm? Have you checked the polarity on the driver in question?
    May be JBL D16R2425 (Ti diaphragm) would be acceptable if for sure the diaphragm is the problem. Its price is about half of the mentioned D16R2421 (Al ).

  5. #5
    Senior Member
    Join Date
    Aug 2010
    Location
    Jättendal (Giant Valley), Sweden
    Posts
    736
    Quote Originally Posted by ivica View Post
    May be JBL D16R2425 (Ti diaphragm) would be acceptable if for sure the diaphragm is the problem. Its price is about half of the mentioned D16R2421 (Al ).
    I wouldn't recommend titanium diaphragms. Go for Radian (US made!) diaphragms. Or used JBL aluminium diaphragms, they appear from time to time on ebay.

  6. #6
    Senior Member BMWCCA's Avatar
    Join Date
    Feb 2006
    Location
    Virginia
    Posts
    6,964
    Quote Originally Posted by karina View Post
    I just brought back my JBL L300 from almost 2 years in restore .
    I connect and everything sound good but one of the compression driver (LE83) sound "cracky" at some freq .
    Have you swapped the drivers side-to-side to isolate a driver problem from the crossovers? Elementary I know, but you didn't say.
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

  7. #7
    Junior Member
    Join Date
    Jul 2010
    Location
    NA
    Posts
    19
    I did play with the lpads - it's not the source for the noise .
    No doubt i should change the lpads - can any one recommened on matching lpads?


    I'm almost positive it's the diaphragm but not sure which one i should buy ,
    As it look most of the recommendation is NOT going on titanum cause of the sonic difference .


    Found this page for JBL replacmenets:
    http://reconingspeakers.com/wp-conte...-le8500011.pdf
    But again - in many other threads i found that the correct impadance for LE85 diaphragm is 16ohm when it's in
    3 ways and 8 ohm for 2 ways.
    So not really sure what should i buy and replace.



  8. #8
    Senior Member SEAWOLF97's Avatar
    Join Date
    Jan 2006
    Location
    PDX, ®egon
    Posts
    9,111
    Quote Originally Posted by hatrack71 View Post
    Have you swapped the driver to the other L300 to confirm?
    Quote Originally Posted by BMWCCA View Post
    Have you swapped the drivers side-to-side to isolate a driver problem from the crossovers?
    Quote Originally Posted by karina View Post

    I'm almost positive it's the diaphragm but not sure which one i should buy ,

    2 senior members have recommended swapping the drivers , (so I didn't need to) , but that
    is the next step b4 you start spending $ .
    “If you think that’s the dumbest thing you’ve ever heard,
    just wait a couple minutes!”

  9. #9
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,985
    Quote Originally Posted by karina View Post
    But again - in many other threads i found that the correct impadance for LE85 diaphragm is 16ohm when it's in
    3 ways and 8 ohm for 2 ways.
    So not really sure what should i buy and replace.
    I agree with Seawolf... do a bit more work before you start throwing more money on the project.

    As for the impedance, you must be reading the wrong threads or you are misinterpreting them.

    The LE85 is ALWAYS a 16 ohm driver. I won't bore you with the details, but trust me on this... regardless of what you may read elsewhere including on the foilcals.


    Widget

  10. #10
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,672
    If the drivers have been in storage it's possible that they have corrosion on the terminals of the diaphragm under the back loading cap, maybe corrosion in the voice coil gap itself and probably rotted foam pads.

    Sounds like they might benefit from a thorough cleaning if they've been in idle storage for a while.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  11. #11
    Junior Member gdwrench's Avatar
    Join Date
    Jul 2011
    Location
    Westland,Mich
    Posts
    22
    Quote Originally Posted by edgewound View Post
    If the drivers have been in storage it's possible that they have corrosion on the terminals of the diaphragm under the back loading cap, maybe corrosion in the voice coil gap itself and probably rotted foam pads.

    Sounds like they might benefit from a thorough cleaning if they've been in idle storage for a while.
    I 2nd this motion !!

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Any fix on noise from bass?
    By pyonc in forum General Audio Discussion
    Replies: 14
    Last Post: 11-13-2011, 10:12 AM
  2. Laptop noise down the PA
    By GCT in forum Lansing Product DIY Forum
    Replies: 4
    Last Post: 10-22-2011, 11:22 AM
  3. Port Noise
    By analogman in forum Lansing Product Technical Help
    Replies: 9
    Last Post: 09-13-2005, 11:41 AM
  4. Noise from BX63
    By leif in forum Lansing Product Technical Help
    Replies: 15
    Last Post: 08-15-2003, 01:38 PM
  5. Noise in 2235H
    By Guido in forum Lansing Product Technical Help
    Replies: 27
    Last Post: 07-17-2003, 02:15 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
  •