why does my .amr recording sound stretched, robotic, low pitched
Reply #1 –
If it's an Android phone, and the future conversations are important, you might prefer something like the AndRecorder app, which can record in PCM audio (uncompressed) for later conversion if you wish (into MP3, Vorbis, AAC, Opus or whatever) or lossless storage (e.g. FLAC). It will operate at 11025, 22050 or 44100 Hz sampling rates in mono on my ancient phone and I use it for recording song ideas from time to time (AMR is not good for musical content). I found that 22050 was more than adequate for high quality conversations. The uncompressed bitrate for mono at 22050Hz, 16-bit is 352.8kbps (159 MB per hour). Double or halve that for 44.1 or 11.025 kHz respectively.
I have been able to play back AMR content in Audacity (imported using FFMPEG libraries), usually from my Android 3GP videos, but I think I was also able to import AMR from Voice Recorder also, but I just tend not to record using Voice Recorder since installing AndRecorder.