Godden Studios

One of the first steps to successful audio mixing is properly setting channel trim controls. Also known as gain, trim should not be confused with the channel fader or level control. Most consoles have a trim knob near the top and a fader at the bottom of each column of channel controls. As a rule, the trim is set for a given sound source and left. The fader is then used to make level adjustments during the program.To minimize self-noise and distortion, audio consoles mix signals at line level. This is well above microphone output levels. And mic levels vary greatly due to differences in sensitivity and in the levels of the sounds they are picking up. Trim adjustment provides the amount of gain needed to bring the incoming signal to the optimum mixing level. Gain simply means “more of the same.”

Setting the trim correctly is important yet simple. First, mute, or otherwise turn off, all channels but the one to be adjusted. You should also bring the mixer’s Master level controls all the way down, or simply turn the power amplifier down or off to avoid feedback. Turn the gain control all the way to the minimum position, usually fully counterclockwise. If the channel has a Pad or Attenuator switch it should be in the off position unless the gain range proves insufficient for a high-level source. Set the channel fader (or rotary level control) to the nominal operating mark adjacent to the control. This may be a heavier line, or a “U” for unity gain. Engage the channel’s solo button, making sure it is in the PFL (Pre-Fader Listening) mode. (This is to route the channel’s signal to the mixer’s PFL solo metering. Your mixer’s means for doing this may vary.) Next have someone speak, sing or play into the microphone at the distance and level at which it will be used. Now turn up the channel’s input trim. You should see the channel’s input level on the mixer’s meters. Adjust the trim to achieve a level of around zero dB.

That’s it! Now just repeat the procedure for each channel and you’re on your way to better sounding mixes.

Greg Silsby, gregs@mackie.com (Commercial Sound Specialist with Mackie Designs.)

Aim to apply as little processing and effects as possible, but instead capture the sounds as close to intended as possible with mic placement, good playing/singing technique, dynamic levels etc..

Make space in the mix for each sound, both dynamically and in the frequency spectrum

More important sounds the middle

Reverb tends to send sounds into the background

Distortion introduces harmonics which fill up the frequency spectrum. Guitars need a lot less distortion that guitarists think

Can split two or more tracks by playing top 3 strings on one and bottom 3 on the other. Need to ensure both takes are accurate in timing. Then apply distortion to lower 3, and less to top 3. Or split whole track and apply some distortion to one, mixing in with the dry one to form a fuller sound.

Double-tracking vocals also requires timing accuracy and may add depth, but often doesn’t. Backing vocals can receive much more processing than lead vocal. Lead vocal should be recorded as clean an accurate as possible as alterations are more noticeable than with backing vocals.