Here's what I'd do.
- Open in SoundForge
. Copy tiny section of noise-only audio. For this file, about a third of the "silence" before the music starts is good enough. It doesn't have to be real long. File > New. (Be sure new file has EXACT SAME specs, like 44.1kHz, stereo, etc!) Paste. Save as NoisePrint.wav. See attached.
- Close all files in Sound Forge
. Open Audacity. File > Open main audio. File > Open noise print. (Do not drag both into Audacity! Do File > Open twice, otherwise you'll end up with both audio files overlapped. You need them in separate windows.)
- Select all (CTRL+A) the noise print. Go to Effect > Noise Removal. Click on Noise Profile button. Now click on windows with main audio. Go to Effect > Noise Removal again. Try a preview at the default settings. See how it sounds. My default is 18 right now, because that's what I used last time. I forget what the true default is, from the first time you use Audacity. (It remembers the settings between sessions.) If it sounds good, then try it with a low number. Ideally, you want to use the lowest number possible. Over-filtering is bad. Under-filtering isn't great. Like the Three Bears, you want it to be just right. For this exact file, I think 18 is the best setting. Some hiss is left, but it's almost inaudible (for now). OK!
Okay, now that's done. File, Export, save the new WAV. Give it a new name. "Filename
Restored Pass1.wav" is good. See attached.
Why Pass1? Well, your audio is low. Really low. It needs to be normalized higher. In effect, you'll make things "louder" (although normalizing IS NOT VOLUME!), which includes noise. Yes, this means you'll end up de-hissing/humming twice.
- Open new restored audio in SoundForge
again. Use the digitalFAQ preset for normalizing, 80% DVD. Or manually change it to about 80%, if you've not installed the filter pack from this site. (Install it!) Okay, done. Save.
- Repeat Steps 1 and 2. (See attached Noiseprint Pass2.) Then Repeat Step 3, but you may need a different value this time. Start at 18, see if it needs to differ. I think 22-24 might work better this time around. There's a metallic hiss in the high registers that would drive me bonkers at 21 and below. Okay, OK filter. File > Export, save as new file. (Attached.)
Done. This wasn't even a hard one.