Removing broadcast hum from TV recordings?
 

Are there any audio programs that can remove broadcast hum from television? I’d like to record music off DVDs (the fidelity is already excellent), but I’m hoping to filter out that inherent TV hum so I can listen closer to CD quality under headphones. Thanks!

SoundForge, Audacity and Goldwave.

SoundForge is not the best for this task, as the methods described on this site use SF for frequency carving to restore sound. This error can be corrected without carving.

Goldwave works well at removing this, but has a bad by-product of tinny metallic noise afterwards. So it's not the best solution, although it can work.

Audacity generally works the best for this specific error, but it depends entirely on being able to isolate a "pure noise" pattern. (Goldwave was the same, for ideal workflow, but could still reduce it without noise print.)

None of this is obvious in any of the programs. Most people choose a "quick" method that isn't best for archival quality. Each of these really needs a dedicated guide on this site -- and those are on the way.

If you can attach a sample WAV file (or MP3/AC3, whatever), I can look at it, remove the noise, then quickly describe what was done. You'll catch on quickly, for this one task.

Awesome, thanks Lordsmurf. :)

I've attached what I think is a good song clip to do this on, with a quiet beginning and end. If you need the full song (more data), please let me know. I don't have the Lame encoder on this computer and couldn't create an MP3. It's a shortened WAV file. Thanks again!

Here's what I'd do.

STEP 1 - 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.

STEP 2 - 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.)

STEP 3 - 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.

STEP 4 - 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.

STEP 5 - 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. :cool:

Great, thanks Lordsmurf! :)

besided that song being terrible, didn't think it had too much wrong with it,have heard so much worse, hiss, hum and other issues......