jbl 076 tweeter diaphragm

[FREDFLYPOGGER]

Hi
I picked up a pair of 076/2403 cats eye tweeters. Diaphragm installed are the 2405 which are wrong but they do work one plays much lower than the other. I want to replace diaphragms but D8R076 are discontinued.Speaker exchange says he D8R075 can be used but it requires driver modifications. Does anyone know how to or know what has to be modified to get this diaphragm to work?
thanks
todd

[toddalin]

Piece of tape or a shim.

There are videos of the tape method on-line and at one time when I had a 2405 professionally (OCS) put in a 2402, I made a shim from thin plastic. But use original 2405 diaphragms and you will probably be happier with the results.

If one is lower in volume, it/both has/have been compromised.

It may have been replaced with an inferior piece, or maybe you have a 2402 (louder) and a 2405 (quieter), or perhaps the phase plug wasn't held steady on re-assembly and this put a wrinkle in the diaphragm, or... Any of these will affect the volume.

[1audiohack]

Hi Todd and Todd!

The 076 and 2405 diaphragms are identical from the voice coil in and the inner rings are the same, that makes the D2405 the proper replacement for the 076.

The 076 driver uses the 2404H phase plug which is 1.720" at the base. If you really wanted to use the 075 diaphragm the plug to use would be the 2404-1 which is 1.600" at the base.

All the best,
Barry.

[FREDFLYPOGGER]

Hi Todd and Todd!

The 076 and 2405 diaphragms are identical from the voice coil in and the inner rings are the same, that makes the D2405 the proper replacement for the 076.

The 076 driver uses the 2404H phase plug which is 1.720" at the base. If you really wanted to use the 075 diaphragm the plug to use would be the 2404-1 which is 1.600" at the base.

All the best,
Barry.
Hi Barry,
So I would use the D16R2405 diaphragm? Any modifications needed? any sound difference?
thanks
Todd

[1audiohack]

Hi Todd;

The D16R2405 is the JBL suggested replacement part.

Having never owned or tested / measured an 076 I am uncertain what the differences might really be.

I really should own a pair.

Barry.

[grumpy]

I would expect differences... as there are differences in intended use between
the 2402H and 2402H-05 (the latter, a factory mod to accept a D16R2405)
or 2404H and 2404H-1 (the latter modified to accept a D8R075)

Feel free to double-check me, as I'm going from memory.

A tradeoff in handling lower frequencies (075 diaphragm) vs extended (higher) response (077 diaphragm)
as well as some in-band frequency response differences might also be expected.

There is an enormous thread on the differences between ring radiators, but I don't recall
your particular case being documented with response curves (076/2403 with a different diaphragm)