Film-Tech Forum ARCHIVE: JBL 4632-M/HF, JBL 4632 M/HF-T

This is topic JBL 4632-M/HF, JBL 4632 M/HF-T in forum Ground Level at Film-Tech Forum ARCHIVE.

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Posted by Thomas Baham (Member # 9113) on 10-13-2018, 06:28 PM:

I am looking for some help on converting a JBL 4632 Tri Amp to a Bi-Amp. Is this possible? I purchased two Bi amps and a sing tri Amp (Unknown to me, I goofed up) and now my sound guy says I need a Bi amp speaker. Is there anyway to convert the Tri amp to Bi amp? Or just connect one amp to both terminals on the Hi's and Mids? Need help, opening my theater in 2 weeks. Thanks

Posted by Steve Guttag (Member # 268) on 10-14-2018, 08:41 AM:

You have some work ahead of you.

You'll need to obtain the part 129-20064-00 which is a crossover network to allow the MF and HF to play from a single amplifier channel.

The crossover network, I believe mounts in the Mid-range assembly between the lower two drivers and the upper two. There should be a molex connector that provides the input/output connections for the crossovers. Swapping the Tri-amp version with the Bi-amp version should allow you to convert it.

I've never personally done this so I can't confirm first hand.

The part still shows as available so you should contact your JBL dealer for it.

If you hook your amp up to both the HF and MF in parallel, you'll destroy your HF driver (it would try to reproduce frequencies beyond its capabilities...hence the requirement of a crossover).

If you choose to try an aftermarket crossover, the crossover frequency is nominally 1.2KHz between the upper Mid and HF, but you'd have to wire it in the correct place (still located in the MF section).

Posted by Thomas Baham (Member # 9113) on 10-14-2018, 06:36 PM:

Thank you Steve, my sound guy decided to add a third amp for that one speaker. He said it would be much easier. Thanks again

Posted by Steve Guttag (Member # 268) on 10-14-2018, 10:52 PM:

Hopefully, in addtion to the amp, he is providing you with the proper active crossover too. The speaker itself provides no crossover for the HF section at all.