T1 ToneMatch® Audio Engine / Gain Staging

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T1 This information is applicable to the T1 ToneMatch® audio engine

Gain Staging

Your first adjustment for any input to your T1 ToneMatch Audio Engine 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.

T1® Trim Pots

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.


Bill-at-Bose [1] talks about setting the gain on a T1 ToneMatch Audio Engine.

One difference in gain staging the T1 and the Classic is that the T1 has a three-stage trim LED. It lights up green when signal is present, yellow when you are getting pretty loud (8 to 10 dB of headroom left), and red when you dangerously close to or at full scale.
In a way, the yellow trim on the T1 is similar to how you treat the red on the Classic. Some yellow during peaks is good on the T1, just like some red on the Classic is good.
If the T1 trim is going red, you should back off, you are definitely nearing or in compression.
A really helpful feature on the T1 is to go to the Prefs/Output Level menu, and see where you are relative to maximum output.

T1 Prefs Output Levels Master.png

T1® Trim Pots

The T1 trim controls for CH 1-3 provide a significant gain increase when you reach the upper limit. This increase in gain is normal operation.

Most sources like typical microphones and piezo pickup systems can provide enough level without the need to add significant gain from the trim control. Certain sources like passive acoustic guitar pickups require additional gain and in these cases it can be necessary to set the trim level to the upper range of the control. When the trim control is set this high you may notice the gain change. This is normal operation. If you want to run the trim control at lower settings we recommend using a preamp or simple stomp box level booster.

The trim for CH 4/5 do not exhibit the same behavior (as the trim controls for Channels 1,2,3) as these inputs are designed for line level sources and do not have the same gain staging as CH 1-3.

Source: Craig-at-Bose 2008/11/03