Voice recovery with high-noise, low-gain I have a recorded interview with two speakers, in which one voice's gain was much higher than the other (by three orders of magnitude). Increasing the gain does not help, because speaker 2's voice is so quiet that it is hitting the digitization limit (I believe). Audio quality is not important, but it would be very helpful to have an approximate technique so that the words may be intelligible. 

If helpful, I can try to post an audio example of the specific distortion here. The cadence of the voice is there, but it's so mangled the words are unintelligible. Basic interpolation and filtering (both long shots) were not successful in recovering the voice.

Any suggestions for analysis techniques and/or software would be much appreciated.
I would suggest dynamic range compression as a first port of call. Set the threshold low and the ratio quite high. Then apply make-up gain to an appropriate level. This functionality is built into many free audio editors such as Audacity. Matlab or Python implementation is also reasonably simple.