[darkstar999]

96kbps is pretty high for voice. You could get away with 48 or less.

[funkyy]

64kbps would be sufficient to hear back noise and whisper, so that would make more sense.

[lozf]

Way less with modern speech codecs. Even Opus at 32kbps would be overkill for the required quality.

[throwaway7767]

Opus is quite usable for speech data down to 8kbit/s, even 6kbit/s is mostly understandable. At 10-12kbit/s you have good quality voice recordings.