procedure GetVolumeRange(out VolumeMindB: single; out VolumeMaxdB: single; out VolumeIncrementdB: single);
The GetVolumeRange method gets the volume range, in decibels, of the audio stream that enters or leaves the audio endpoint device.
Result: stored in self (calling object)
Remarks:
Reference: IAudioEndpointVolume on msdn.microsoft.com.