Most consumer-hardware I know will have positive gain on the computer output (all built-in audio for my devices, the PCI cards with Ensoniq 1370 or 1371 I used

Most consumer-hardware I know will have positive gain on the computer output (all built-in audio for my devices, the PCI cards with Ensoniq 1370 or 1371 I used earlier). On the other hand, a lot of the professional audio equipment I know have mixer-applications that has either 0dB as a maximum setting, or clearly labeled 0dB marks/buttons on the mixer application). You can verify it easily by playing either a 0dB sine-wave mp3 (first google hit: http://www.dr-lex.be/software/testsounds.html http://www.dr-lex.be/software/testsounds.html) or trying to get a sine-wave test-tone generator. You'll hear the point where distortion kicks in pretty drastic as soon as you reach the clipping level. With a spectrum-analyzer (e.g. FrequenSee on Android) even slight clipping will be very visible (peaks at 3x, 5x, 7x, ... the base frequency will suddenly appear).