Small Practical PA

Small Practical PA

       Here we have added monitors and effects. The monitors are the speakers that face back toward the stage so that the people there can hear themselves singing. They require a separate equalizer and amplifier and are hooked up in the same configuration as the mains (mic to mixer to EQ to amp to speaker), except that the cord running to the input on the monitor EQ is coming from the "Monitor out" channel on the soundboard rather than the "Main out". Basically what has happened is that the signal that has left the microphone has been split by the internal electronics of the soundboard into two separate signals. One signal is then routed through the "monitor out" into the monitors while the other is routed through the "main out" into the mains. This makes it possible to adjust the sound coming out of the monitor speakers separately from the sound coming out of the main speakers.

Note:        If you are using a stereo equalizer, you can run the mains through one channel of the EQ (say channel "A") and the monitors through the other (channel "B"). Just remember which channel you assigned to the mains and which you assigned to the monitors.. That way you know which sliders and knobs adjust each part of the system. Doing this avoids the need to purchase a separate EQ, and allows you to fully utilize the equipment you already have. This same principle can be applied to any stereo components in the system such as amplifiers, compressors, and crossovers, etc.....

       The effects help to thicken out or modify the sound that is going through the PA system. There are many different kinds of effects including such things as delay (echo), reverb, and chorus. These can be hooked up "in line" or directly in the path of the signal, but are much more versatile when hooked up in an "effects loop". An effects loop is created when a signal is sent out of the soundboard into and through whatever effects you are using and then "loops" back into the soundboard. Once this loop is set up properly, the effects can then be adjusted individually for each input channel (microphone, keyboard, etc...) on the soundboard. This means you could put a lot of echo on one guys vocals while adjusting another guys to have almost none. On the other hand, a digital delay (echo effect) in line with the mains....say, between the mixer and the EQ....would affect everything coming out of the main speakers equally, and everyone would have the same amount of echo.

Now that we have examined the concept, here's how you plug it all in:

Mains

1. Connect everything together as described in example 2. This is essentially the signal path for the mains.

Monitors (Remember, signal path flows from the microphone toward the speaker.)

2. Plug a high Z cable (patch cable) into the "Monitor out" of the mixer.
3. Plug the other end of this cord into the "input" of the monitor equalizer.
4. Plug one end of a high Z cord into the "output" of the monitor equalizer.
5. Plug the other end of this cord into the "input" of the monitor power amp.
6. Plug two speaker cords into two speaker "outputs" on the monitor power amp.
7. Plug the other ends of these cords into the "inputs" of the monitor speakers.

Effects loop

8. Plug a patch cord (usually high Z) into the "effects send" or "effects out" of the soundboard. This is where the signal leaves the mixer (you are sending it out of the mixer).
9. Plug the other end of the cord into the "input" of the effects unit.
10. Plug another High Z cord into the "output" of the effects unit.
11. Plug the other end of this cord into the "effects return" or "effects in" on the soundboard. This is where the signal returns to the mixer thus completing the effects "loop".

Multiple effects

       You will probably want to run several different effects at the same time. This can be done by either using a multiple effects unit that will run many effects simultaneously within a single unit, or by putting several different effects units in line within the same effects loop. "In line" simply means hooking them up in a row such as in the following example.

       In this case the signal flow is coming from effects send and flowing toward return. Remembering that the inputs are always on the upstream side of the flow, the "inputs" in this situation will always be coming from the effects send jack, and the "outputs" will always be going toward the effects return jack. Thus we have a signal path like this:

Effects send (from the board) to Input (on the delay) to Output (on the delay unit) to Input (on the Reverb unit) to Output (on the reverb unit) to Effects return (on the board)

       Some soundboards are equipped with more than one effects channel. All you need to remember is that if you used the effects send from channel "A", you have to use the effects return for channel "A". If your board has more than one effects channel, you can set them up totally independent of each other. This gives even more control when adjusting the sound to the individual mixer inputs (microphones, etc...).

- Source (thefxcode.com)