Using noise reduction and other filters typically won’t make incomprehensible speech pop out from noise. If your wetware (brain), which is better than current computer hardware, cannot make out what is being said it probably still won’t be comprehensible after noise reduction.
The stuff you’ve seen on CSI where a voice is extracted from pure noise is pure fiction.
Standard procedure to make voice recording clearer …
- Amplify
- Apply noise reduction: (it’s a two step process).
- Apply a narrow band pass filter: remove the frequencies below 200Hz and above 6KHz using the equalizer.
4 Amplify again if necessary.
If you attach a 5-10 seconds of the recording to your next post we could tell you if you are flogging a dead horse, (bear in mind this is a public forum anyone can hear/download from it).