Define audio, do you mean people talking or music? Music is not too hard but speech would be harder there can be long pauses occasionally. Your multimeter more than likely is reporting the wrong voltage unless it's a true RMS meter rated for the full audio spectrum, most meters are calibrated for 60hz AC only so the results you got measuring AC voltage aren't valid.
If you can describe a little more about exactly what kind of audio you need this to switch on for it'd be easier to make suggestions.