> println("levelMeter = \(levelMeter.mPeakPower)")
> [self writeJavascript:[NSString stringWithFormat:@"receiveVolumeLevel(%f)",levelMeter.mAveragePower]];

前者は levelMeter.mPeakPower を、後者は levelMeter.mAveragePower を測ってるのだが何故？