Synchronization Loop Connection for 2-channel Measurement

To perform a 2-channel measurement in loop-back mode, the loop-back must be mixed with the measurement signal in one of the channels. How this is best done depends on if your sound card has one or two input lines.

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2-channel loop-back for sound cards with one input only

2-channel loop-back for sound cards with two inputs (e.g. line and microphone input)