Help on removing noise


I have been making some open-reel digitizing for my school. There were 72 english listening comprehension tapes all the way from the 1977 to 1998. Most of the tapes were in very good condition, but some of them had a really nasty background noise, kind of ticking. It’s not very loud but it can be still heard over the program and it’s kind of annoying when you notice it (really wouldn’t make a 45-minute-listening-comprehension easier!) I put a small example for you in here:

Do anyone have an idea how to remove that noise? I have tried the noise removal -plug-in but no success, as this seems to be too variable kind of “noise”. It sounds that the problem is not on the tape copy itself, as the noise begins and stops clearly with the program itself (at the beginning there is some empty tape and then small “click” and both program and noise start. So I assume that the noise has been on the master tape already, or there has been some trouble with the recorger used).

Otherwise I have been very pleased to use Audacity, it has never crashed and it’s very practical to use.

Thanks for any help in advance!

It was easy to remove using version 1.3.3.

In that example, I just selected the first 1 second of Audio, used that as the Noise Profile in the Noise Removal, and then went back and selected everything, changed the Noise Reduction slider to 20 dB and it worked fantastically.

The Noise Remover has been vastly improved in the newer versions of Audacity. Hopefully the unwanted noise is pretty similar amongst your files, that way you should be able to set up a Batch function to do everything for you. I would tell you how, but I haven’t used the Batch functionality yet.

Thanks for your tip!
I have been triying with the noise removal filter but I haven’t found the correct settings, as with too much noise removed there will be some other troubles. I’ll try again this weekend and let you know.

Still something to ask…

How should I decide the other noise removal -options? (Referring to the newest version of Audacity). The amount of noise to be removed with the dB -scale is known, but how do the other settings affect? Also I have noted that removing noise with the filter can bring a new problem: in this case, in the speech, if the speaker breaths in loudly between the sentences, the breath is partly removed by the filter, but the remaining has a new “metallic” effect (which I found very annoying!). Personally I think that the effect is so annoying that I prefer keeping the noise instead of removing it as the result is that. (If you can’t understand what I mean, I can try to make an example later this week. It’s a bit difficult to explain in the text! :slight_smile:)