Thanks for the file. I think the sound quality is pretty decent for a voice recording. Only when using headset I was able to hear sound artifacts (on "a" or "e" vowels).
Diarium uses AAC-HE encoding to get a good audio quality on low bitrates (32kbps when using standard attachment quality, 48 kbps with better attachment quality). I don't want to increase those values as I heard of users that want to record very long audio files (sometimes over an hour long) and with a higher bitrate, the 32MB attachment limit would be reached quicker.
What I can try and will implement with the next update is to record audio files (on Android only) in Mono instead of Stereo, so the 32kbps won't get split between 2 channels. In my tests the recorded audio naturally sounded "flatter" due to the single channel, but I was no longer able to hear audio artifacts. Would be great to hear your feedback on this change which will be part of the next update
