JBL LX 16 Crossover conversion

[JBeL]

On the schematic for the LX16 it suggests converting it to a LX16A.
This is to protect the high frequency driver it says but l was wondering if it changes the crossover frequency as well?
The cap and inductor are changed from a 1.2mH to 0.7mH and the cap is changed from a 12uF to 6uF only on the LE85 high frequency driver the bass components stay the same.

[audiomagnate]

On the schematic for the LX16 it suggests converting it to a LX16A.
This is to protect the high frequency driver it says but l was wondering if it changes the crossover frequency as well?
The cap and inductor are changed from a 1.2mH to 0.7mH and the cap is changed from a 12uF to 6uF only on the LE85 high frequency driver the bass components stay the same.

That's exactly what it does (raise the crossover frequency) and rather significantly at that.

[Eric M.]

Brining this thread back to life.

So, if the LX16A was modified for a higher crossover point at the high end (to protect the LE85) and nothing was done to the low end circuitry, wouldn't you end up with a gap in the response?
The original LX16 crossed at 1200 Hz, I have no idea what the new HIGH end crossover point is after the mods to LX16A, I don't think JBL ever published that .... and how would that look - 1200 Hz at the low end and 2500 Hz at the high end?? That wouldn't help sales!
But as stated above, t's a big jump based on the changes to the high end cap and coil.

Has anyone ever noticed a dip at that frequency point on the L200 with the LX16A mod or any speaker configuration using the LX16A?
Maybe the LX16 offers a smoother response if you can keep your listening level low enough not to damage the LE85 (something I could never do when running an LE85 with an LX5 back in high school!)

Thanks,
Eric M.

[Epplerd]

Brining this thread back to life.So, if the LX16A was modified for a higher crossover point at the high end (to protect the LE85) and nothing was done to the low end circuitry, wouldn't you end up with a gap in the response?The original LX16 crossed at 1200 Hz, I have no idea what the new HIGH end crossover point is after the mods to LX16A, I don't think JBL ever published that .... and how would that look - 1200 Hz at the low end and 2500 Hz at the high end?? That wouldn't help sales!But as stated above, t's a big jump based on the changes to the high end cap and coil.Has anyone ever noticed a dip at that frequency point on the L200 with the LX16A mod or any speaker configuration using the LX16A?Maybe the LX16 offers a smoother response if you can keep your listening level low enough not to damage the LE85 (something I could never do when running an LE85 with an LX5 back in high school!)Thanks,Eric M.

Resonant circuitry calculations show crossover frequencies of around 1.3khz and 2.4khz for the LE85. This would imply a slope of 12db/octave, subject to any other crossover components other than the capacitors and inductors mentioned.

[Eric M.]

That would indicate 6 dB down at the actual crossover, intersection point of about 1850 Hz, 3 dB more that what is desired at that point.
So it seems there would be about a 3 dB dip in the response of the LX16A at around 1850 Hz as apposed to the LX16.

Has anyone ever listened side by side (or tested) the LX16 vs 16A? I'd be curious to know how noticeable that dip is.

[Eric M.]

I have a client who has a pair of LX16 and LX16A crossovers. He wanted to rebuild a pair for his L200s. His mother was the original owner, they are original with the LE15B, 8 ohms and the LE85, 16 ohms, there have been no changes or mods done since new. He sent me one LX16 and one LX16A and kept one of each for himself - a LX16 in one speaker and a LX16A in another. The plan was to rebuild the pair he sent me as LX16A. I rebuilt one and did some listening with some basic speakers I had in the shop. I really felt there was a gap in the crossover as mentioned above. I asked him to do a comparison with the LX16 and 16A he had in his speakers. He reported the same. Now, this could be due to his LX16 being 50 years old or it could support my claim above. He has opted to rebuild the crossovers as LX16 not 16A.

I have one crossover presently rebuilt as a LX16A and will do the second as a LX16. I want to run some comparison tests on both before changing the first LX16A rebuild over to the LX16 design. I'll post up the results once done.

Eric M.
MCIaudio