2 replies to this topic

[NoN0]

Hello,

I work in a theatre and I inherited a rather strange amp/speaker set-up from my predecessor: we have 2 EAW JF250 subs and 4 EAW JF 50 that are used as a surround system. These are driven by two Crown Macrotech 2400’s. But the strange thing is: each amplifier drives 1 JF 250 (sub) and two JF50’s – instead of using one amp to drive 4 JF 50’s, and one to drive the two subs. Both amps use PIP-modules for crossover needs. Anyone know why anyone would hav e to chosen to build the system this way, and what-if any-the benefits are of this setup?



Thanks in advance!

[Bradford Benn]

Depending on the PIP card, it is a result of the way the Xover is done. If it is a PIP-XOV card, the highs go to channel 1 and the lows go to channel 2. So doing it the way you described is the practical way to acheive it.

[brubart]

One advantage of the existing setup is that, if one power amp fails, the audience still hears a full-range sound from one sub and two surround speakers. If the subs were on one power amp and the surrounds on another, and the surround amp failed, the resulting sound would not be usable.

Still, if you want to put the subs on one amp and the surrounds on the other amp, you can do that by changing switch settings in the PIP-XOV card.

Set one amp's PIP-XOV to Mode 1: both channels receive a lowpass signal to drive the subs.

Set the other amp's PIP-XOV to Mode 7: both channels receive a highpass signal to drive the surround speakers.

The link below goes to the discontinued PIPs page, where you can download the PIP-XOV manual. It tells how to set the switches to get various crossover modes.

http://www.crownaudio.com/gen_htm/legacy/legacpip.htm

Hope this helps,

Bruce Bartlett
Crown Technical Publications