In a 6000 seat
venue, I am really surprised the management isn't listening to your cries for expert help with the sound
system. You have not supplied enough information for anyone to tell you exactly what you need to do, but I can
point out some potential "gotchas." If any of this is stuff that is obvious to you, please don't take offense; I will try to explain from a very basic knowledge
level in case you are very unfamiliar with PA systems.
Just beyond your
mixer main outputs, you should have some sort of
equalizer for operators to use. After that, you should have a
crossover, which may be located at
FoH or near the amplifiers. Its function is to take the full-range signal (say 20Hz - 20kHz) from the
mixer/EQ, and divide it into several frequency bands for the different speakers you have, for example, 35Hz - 90Hz may be routed to your
subwoofer amplifiers, and you may have L/C/R inputs and outputs for your main loudspeakers, which sound like they only use a single
amplifier channel each. Assuming you find such a
crossover in the PA
system, you will need to identify which output should go to what group of amplifiers. If you do not find any
crossover unit, you may have bigger problems (as there may be no protection from extremely low-frequency content, which can quickly damage speakers.)
Once you have determined which outputs go to which speakers, you need to figure out the
amplifier situation. Splitting one signal into two or more amplifiers is very easy. Unlike
DMX, you can simply use a "
Y cable" without any fear of signal degradation. As long as you do not need to connect more than 10 or so amplifiers to a single source, don't make it hard, just buy "Y cables" or solder yourself up a
patch panel or wiring harness. Here is a $10
Y cable:
YFM&YMF the YFMM type is the correct gender for your use.
Now that you know how to split up the signals, you still have to figure out which
speaker cables go to which speakers. As long as none of your speakers are bi-amplified (or, requiring separate amp channels for their HF section) you can use this easy method: Hook up one
amplifier to your
mixer,
plug in an iPod or laptop,
play some music, and then connect each
speaker cable to that amp
channel until you have found and labeled the cable for every
speaker. Of course, if you are installing new speakers (and cables) you may find this is not necessary; but it is always a good idea to verify that the cable pullers have labeled everything correctly before you continue working.
Now you want to decide which amplifiers are used for which speakers. This is complicated and if you don't already know, you should post much more detail including what speakers and amps you have, and what area each
speaker is intended to
cover. I'll leave this subject alone unless you require more help.
Once you know that, simply hook up the
speaker cables to the designated amplifiers. But you're not done yet.
Since you are changing amplifiers, you need to compare the
Voltage Gain of the old amps to that of the new ones. Your old amps might have 32dB of
gain, and your new ones might offer several choices, for example, 26dB and 32dB. If this is the case, use the same setting on your new amps as on the old ones. If not, you will need to adjust the
gain of the new amplifiers appropriately. Otherwise, you may find the PA
system is now much louder, or much quieter, than with the old amplifiers, given the same input
level from the
mixer. Note that this has no direct relationship to the maximum
power rating of your amplifiers -- a 10000w amp can have the same amount of
voltage gain as a 200w amp. The 10000w amp can simply receive a much stronger input signal before it reaches maximum
power. However, the
voltage gain of amplifiers varies from one series of amps to the next, and often from model to model. Check the spec sheet for your amps.
Finally, if you found a fancy digital signal
processor acting as the
system crossover, it may also have a built-in
limiter, and perhaps many other features. This may be where you need the most help. It suffices to say that the
limiter, if configured, is there to protect the speakers from damage, and if left alone AND you configure the same
voltage gain on your new amplifiers as on your old ones, the PA
system will have the same
driver protection as it did before you changed it. If, however, you increase the
amplifier gain, you need to reduce the
limiter threshold setting by that same amount.
You may wish to go back to management and suggest they budget for someone to come in and assist you, at least with configuring the amps and
crossover/
DSP once they are all hooked up, to protect the PA
system from damage. Otherwise, a simple accident like a dropped
microphone, or a careless user who turns something up too loud, could easily damage some or all the drivers in your PA
system. That would be a costly repair.
I hope this is helpful.
EDIT: One large "gotcha" I have not mentioned is since you are dealing with new cable plant, you will need to check the
polarity of the installed cables to make sure it is correct. This is important, as if the ends of one or more cables are wired in reverse (or hooked up to the amplifiers in reverse) it will have a dramatic affect on the sound.
