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[jimmy powers]

Newbie alert. 1st post.

So, I've got a pair of JBL SRX738 that I'm having flown (by a licensed and insured professional)in my small/medium size church sanctuary. I want to run them biamped ... what's a good amp to do this with?

Specs

Power Rating:

Passive 800w/1600w/3200w
BiAmp LF 800w/1600w/3200w
Biamp HF 350W/700w/1400w

Nominal Impedance:

Passive 8 ohms
BiAmp LF 8 ohms
Biamp HF 8 ohms

I've heard that a speaker should always be over powered by a factor of 3... true?

THANKS!!!!!!!!!!!

[Silas Pradetto]

If you're doing a mono cluster or don't care about stereo, I'd use a single IT6000. One channel on the lows and one channel on the highs and you'll be all set. It has proper limiting for the high frequency section so you'll not blow anything up.

Quote:

I've heard that a speaker should always be over powered by a factor of 3... true?

Very false. A speaker only needs more power until it is loud enough for your application. If the speaker can't handle the amount of power required to get it loud enough then you need more speakers.

There are various thought processes about how to get the most performance out of a speaker, and proper excursion and thermal limiting with a huge amplifier is probably the best way. There is no set multiplier though.

[Brad Weber]

jimmy powers wrote on Tue, 18 August 2009 11:59

I've heard that a speaker should always be over powered by a factor of 3... true?

You usually wouldn't want to 'overpower' anything but what may be appropriate power all depends on what you are trying to do.  Consider that a 3dB decrease in output would relate to half the power, if there is no actual need to have the maximum possible output then you might save some money on the amps.  Do you actually need or necessarily even want the full potential output of the speaker?

And since you are biamping there may be other considerations.  In biamp mode the MF/HF power ratings of the speaker are about 44% or -3.6dB relative to the LF power ratings.  However, it also appears that the MF/HF sensitivity is about 13dB higher than the LF sensitivity.  So if you ran both the LF and MF/HF sections at their rated power handling, the MF/HF section would apparently outrun the LF output by 9-10dB.  Especially if you don't have subs, which seems likely with 18" mains, you could likely power the MF/HF section at a fraction of the rated power and get sufficient output relative to the LF output.  What type of sources are you reproducing and do you have subwoofers?

Another factor may be what you have for external processing.  An amp with integrated DSP may be nice if you don't have other processing but may not be necessary or desired if you do have a dedicated speaker processor.  IS there a speaker or system processor planned?

And just a detail but the SRX738 is not intended to be flown so hopefully you meant the SRX738F, the "F" suffix is the version intended to be suspended.