Interfaces: 192I/O, 888|24, 888, 442Steps:1. On a mono track in Pro Tools, instantiate a Signal Generator plug-in and assign the output of the track to the first mono output. Make sure that the fader is set to unity.2. Set the Signal Generator's frequency to 1kHz and select Sine Wave. 3. Adjust the level of the Signal Generator to your desired reference level. This is typically -18dB for a 192 I/O or an 888.4. Using an AC Voltmeter, measure across pins 2 & 3 of the output XLR (or across the tip and ring of a TRS plug). Adjust the output trim pot until the voltage reads 1.228V (for +4dBu) or .316V (for -10dBV). 5. Assign the output of the audio track to the next mono output.6. Repeat Step 4 and 5 for each successive output.7. Connect the last output to the first input and create a mono auxiliary input. Assign the input to the first mono input and the output to the first mono output. Make sure that the fader on the auxiliary input is at unity.8. Using the voltmeter, measure the voltage across the first output. Adjust the trim of the first input until the meter reads 1.228V (for +4dBu) or .316V (for -10dBV).9. Connect the last output to the next input. Re-assign the input of the auxiliary input track accordingly. 10. Repeat Steps 8 & 9 for each input.11. Congratulations! You're done!