My friend recorded an interview session he had via Skype?I dont know what software he used to record the audio,but the final output was a wma file.Its only later when he played the audio he realized that he can only hear his voice clearly and the other person's voice was very faint.Is it possible to enhance that part of the audio using any software?Any help or advice much appreciated
Audacity can read WMA files with the FFMpeg plugin. Download and install that.
I would probably start with normalization to get the clip as loud as possible. "Effects" - "Normalize".
Then I would run "Compressor" 1-3 times to even out the sound between voice 1 and voice 2.
Then perhaphs finish off by some "Amplify" if needed, 1-5 dB? Depends on what you get from previous steps. It's easy to try the effects out using the preview feature.
For the person with too much spare time
If the interview is not too long... one could probably select the fainter parts of the clip and apply amplification only on those parts. But it's much more work.
First part of that question is about audio software.
A free, open source option would be Audacity. This will allow you to isolate the part of audio where the other person is talking simply by selecting. You can learn how to use it from their Wiki. Commercial wise, Adobe Audition is sold in their creative suite packages. It might be overkill for what you need.
Enhancing sound, or any other kind of media, is tricky business.
I imagine the voice from the other person got picked up through a headset or speakers. Boosting the volume will add noise, make frequency gaps much more obvious, boost ambient sounds, and generally makes the audio sound horrid. There's not much you can do, after all you can't add quality. You can mask the horribleness though.
What you can do is add de-noise effects, available in both Audition and Audacity. This is generally subjective from the source audio and you may loose more than you'd like, but tweaked to the right settings, you can find a midground between loosing less noise and loosing less source audio.
Since you weren't expecting this problem, you wouldn't have been able to prevent as much ambient noise as possible. No matter how quiet you shuffled in your chair or scratched you chin, boosting the volume as much as you'll have to will make these actions very obvious. Sometimes, since these are usually deep noises, using a High Pass effect over these areas can help.
A conversation on Skype usually cuts off the high and low frequencies in sound. Boosting those will boost unwanted noise in those frequencies but it will make the voice sound more legible.