Mixing: Fundamentals Part II

Most of us understand the concept of a basic PA mixer: individual microphone channel volume controls and a master volume control. You can demonstrate the operation of these controls very easily. Choose any microphone volume control. Turn it clockwise. The level of that particular instrument or voice increases. Now do likewise with the master volume control. The "mix" or balance between microphone channels doesn't change but the overall level increases.

But if your mixer is more than a basic mono mixer, you may have several pressing questions right about now. For instance, the mixer doesn't have a single master volume control. Instead it has two controls labeled Left and Right or Submaster Left and Submaster Right. What possible purpose do these have? Better yet, how do you use them? Or maybe your mixer has BOTH "stereo" submasters and a mono master control. NOW which control do you use?

If this seems like old hat to you, don't stop here! You may learn some new application tips in using these "left" and "right" controls. Whatever your background, READ ON!

Place yourself in front of your mixer. Take a look at the controls for Channel One. If your mixer is set up with left and right masters (or submasters), there should be a control on each channel labeled PAN or Left Right. This rotary control is often referred to as a pan pot. Pan is short for panorama and pot is short for potentiometer (another word for level control). The purpose of this control is to adjust the amount of sound going to the left and right outputs (Figure 1). In the center position (usually at "12 o'clock''), the pan pot will feed the same volume to both the left and right outputs. As you turn the control to the right (clockwise), the amount of sound from that channel going to the Right output gradually increases. Turning the pan control to the left will also increase the sound from that channel going to the Left output. This also means that a gradual increase toward the Right output will also decrease the amount of sound going to the Left out put.

You can demonstrate this for yourself. Using headphones (or left and right speakers with the appropriate amplifier), listen to the effect in the overall left and right balance (panorama) as you turn the pan control back and forth. (Note: The left and right (sub)masters should be adjusted for equal outputs.) Next change the left and right (sub)master level controls and listen to the effect. Starting to get the idea?

Right now you're saying to yourself, "But I don't need stereo outputs if I have a monaural speaker system. How can I possibly use this feature?" Good question! There are many ways to take advantage of a stereo mixer in a monaural system. Simply think of the left and right outputs as two separate outputs - not stereo outputs!

Here's a simple example using the left and right controls:

Make certain that the left output is going to the main speaker(s) and associated amplifier(s) and the right output is feeding the cassette deck. (Note: You can use a ''Y" cable to send the right output to both channels of a stereo cassette deck.)

Turn the individual volume controls all the way down.

Turn the pan control for Channel One straight up or "12 o'clock."

Turn the volume control for Channel One up until you reach a comfortable sound level in the main speaker(s). If you don't hear anything, check to see that the left and right (sub)master controls are turned up equally to a reasonable level at least 1/2 to 3/4 or between 5 and 7 on a scale of 1 to 10. You can also check the manual for your mixer to see where the manufacturer recommends these settings to be.

Check and adjust the record level control on your cassette deck for the proper recording level.

Turning the pan control gradually to the right will increase the level of that microphone channel in the cassette recording and will decrease the level in the main speaker(s). Turning the pan control to the left will create the opposite effect.

Repeat this same process for each channel. By using the pan controls, a proper mix can be done for both the main system and the cassette recording.

After you are satisfied with the balance in both the main system and the cassette recording, you can adjust the overall loudness of each with the Left and Right (sub)master volume controls.

You now have an easy method to put the audience or choir microphone only into the recording by putting those microphones in just the right output. By adjusting the pan pot to about "3 o'clock," a piano could be mainly in the record mix but a little piano would be added to the main mix. Any microphone channel with its pan pot in the center position will be at equal levels in both the main and the recording mix.

If your mixer has left and right master level controls and the corresponding outputs as well as a mono(aural) master level control and corresponding output, the mono master output will be a combination of the level settings of the left and right "submaster" controls. If both left and right controls are turned all the way down, the mono output will have no sound output, no matter where its control is set. If only one of the left or right controls is turned up, only the individual channels that have been "panned" or "assigned" to that submaster will be present at the mono master output.

By now you should be getting the idea. This same approach can also be used to set up separate mixes for main and monitor speakers or main and narthex/cry room/nursery speakers or....

by Travis Ludwig © 1996 Internet Sound Institute (www.soundinstitute.com). This article is for personal use only. Any commercial reproduction is not permitted without permission. To obtain permission, contact ISI at hopi@soundinstitute.com

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