Trim Controls Volume Controls Master Volume

T8S

T4S

T1 

Introduction

On the ToneMatch mixers (and many others) there are three controls that affect the volume

• Trim
• Channel Volume
• Master Volume

Questions:

• What do these controls do?
• When do you use the different controls?
• Should they all be the same?

Background

Mixers accept inputs from various sources. Here are some examples:

Input Source	Signal Strength	Output Voltage
Instrument Piezo pickup (no preamp)	Very Low	50–100 mV
Microphone		-30 dBu 1.5 to 70 mv
Instrument Acoustic Guitar with pickup Electric Guitar		100 mV rms to over 1 V rms
Instrument Level Electronic Keyboard	-20dBu
Line Level Consumer	-10dBu
Line Level output from preamps Tip-Ring-Sleeve	0dBu 0.78 V
Line Level Professional Tip-Ring-Sleeve	+4dBu 1.25 V

Gain Staging

Your first adjustment for any input to your ToneMatch mixer is the Trim setting. The exact position of the Trim will vary depending on signal strength of your input source. The correct setting for any particular source may be different from your other sources.

Set Up Your Source

Set your source at the maximum that it will be when performing.

• Microphone

Sing directly into the microphone using close microphone technique (lips just brushing the windscreen). Sing as loudly as you will sing during your performance. You want to set the Trim to work at your maximum volume.

• Instrument

Turn your input as high as it is likely to go during performance.

Set Input Trim

Turn the Trim setting up until the Trim Light is solid green with occasional flickers of yellow. Use the Trim lights as your guide. (The exact position of the Trim knob is not important).

If you see flickers of red (below), turn the Trim down. You are definitely nearing or in compression. Turn the Trim down until there are no red flickers.

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References

• Understanding Signal Levels in Audio Gear

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