-- xtra SoundLevel
-- v0.3 (c) 2018 Valentin Schmidt

new object me
averagePower object me, integer channel -- 0 = left channel, 1 = right channel
peakPower object me, integer channel -- 0 = left channel, 1 = right channel

For details about the returned float values see:
https://developer.apple.com/documentation/avfoundation/avaudiorecorder/1387176-averagepowerforchannel?changes=_2&language=objc
https://developer.apple.com/documentation/avfoundation/avaudiorecorder/1389463-peakpowerforchannel?changes=_2&language=objc