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RE: JBL 2482 Drivers: each sounds different

97.123.224.3

In Reply to: RE: JBL 2482 Drivers: each sounds different posted by jpackard on October 21, 2015 at 21:49:52

"Should the foam rubber in the back cover always contact the dome of the diaphragm?"
No, it should not contact the diaphragm at all. The foam is shot in the Ebay 2482.
2482 drivers are old, if one has been dropped or banged around more than the other, or run at very high power, it may have lost some magnetism, which will affect the frequency response.
The diaphragms also could have a slightly different impedance (or a completely different impedance) which also would affect the output.
And the damping foam being different will also affect the sound, especially if it is touching the diaphragm.
The diaphragms need to be exactly centered in a clean gap to perform "on spec", cleaning and alignment may need to be done on one or both.
As far as switching to M-200, you will be hard pressed to find a pair of old drivers of any brand that have exactly the same frequency response.

Edits: 10/22/15

Follow Ups:

RE: JBL 2482 Drivers: each sounds different - jpackard 00:48:07 10/23/15 (3)
Thanks for the reply, Weltersys.

Today I swapped the the back covers with the different foam rubber damping material. Absolutely no change at all.

So you must be correct. One driver must have a shifted core, irregular gap, or magnet problem. I don't know of any company that can service these drivers.

Any other 2" horn driver with 4 bolt pattern you (or anyone else) might suggest that provides 400hz - 6khz?
- ASk GREAT PLAINS AUDIO if they would take a look - rickmcinnis@dogwoodfabrics.com 08:00:19 10/24/15 (0)
  Compression drivers are compression drivers even though they specialize in ALTEC.
  
  They can re-magnetize the drivers.
  
  These are very fine people. Send them a note.
  
  In addition, I would use wool felt instead of any type of foam in the chamber.
  
  Take care,
- RE: JBL 2482 Drivers: each sounds different - Kloss 07:26:05 10/23/15 (0)
  EV DH1A
- RE: JBL 2482 Drivers: each sounds different - b.l.zeebub 05:30:08 10/23/15 (0)
  The people in the link may be able to help you.
  
  The AlNiCo magnets of these (or any other driver for that matter) is very susceptible to physical shock. So if it has been knocked or dropped at any stage in its life it may well have demagnetized to some degree.
  On the plus side AlNiCo is more immune to heat than any other magnet material.
  - http://www.speakerrepair.com/page/SROFF.html (Open in New Window)

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