Noise removal

[fratz]

I recorded from a casette a dialog with many short pauses. Now I would like to remove background (white) noise from that part of my audio file where nobody speaks. (The noises are disturbing only in the pauses, when nobody speaks.) If I use 'Noise Removal' effect, there is too much distortion in the speach. How can I applicate 'Noise Removal' effect only for those parts which should be silent?

Do you have any idea?

[kozikowski]

<<<How can I applicate 'Noise Removal' effect only for those parts which should be silent?>>>

You can struggle with that, or you can install Audacity 1.3 which has enormously better noise tools. You can have 1.2 and 1.3 on your machine at the same time, you just can't use them at the same time.

I don't remember where the defaults are, but I start at 18dB reduction, 500 Hz Smoothing, and no delay. This will make a lot more sense when you get the tool working.

The dB Reduction affects the amount of noise versus damage, the smoothing affects the bubbling sounds, and I've never found a reason to use the delay. In most cases, the lower the setting the better. A high dB rating will reduce the noise to zero, but will distort the performance. A high smoothing rating will allow noise to poke up between syllables.

Koz

[stearman65]

Alternatively, you can highlight the pause periods and use "Generate Silence" from the effects menu.
Stearman65.

[kozikowski]

Or Edit > Silence. Control-L.

Perfectly correct. I didn't answer the original post. However, I think the original post is wrong.

<<<(The noises are disturbing only in the pauses, when nobody speaks.)>>>

Reducing the spaces to dead zero like that is going to produce a very weird, mechanical presentation. Leo Laporte on KFI Radio has or had a commercial which was done like that. I'm betting it was produced in a very noisy environment and they tried to patch it up by suppressing the noise between the words to zero.

It could be said that it was very successful advertising because it made me pay attention. But I couldn't tell you what the ad was for, just that it was badly produced.

To produce a pleasant show from a cassette tape requires some very careful production that you almost certainly can't do in Audacity 1.2.

Write back and tell us how you came out and what your settings were.

Koz

[fratz]

Currently I use 1.2, but if you confirm, that with the newest (beta) version I can handle my problem more easily, than I can install it...

I see that I can generate silence (or simply decrease the volume) where it's necessary, but how can I select all these parts the most easily? I have too many two-three seconds long parts with pause...

Thank you for all your suggestions!

[steve]

Currently I use 1.2, but if you confirm, that with the newest (beta) version I can handle my problem more easily, than I can install it...

The noise reduction effect in Audacity 1.3 is much better than in 1.2
You will need to select a good (typical) noise sample from a "silent" (noise only) part of the recording, and then experiment with the sliders at different positions to find the optimum settings. Practice on some short sections before applying to the whole recording. (make a note of the default positions before you start fiddling).

You can have both Audacity 1.2 and Audacity 1.3 installed at the same time. You can only use one version at a time. Audacity 1.3 can open projects made in Audacity 1.2, but Audacity 1.2 can not open projects made in Audacity 1.3.

Audacity is a free program, so why not just try it out?

[fratz]

The noise reduction effect in Audacity 1.3 is much better than in 1.2

That's true. I've installed it and the result to remove noise is much better.

Thank you very much!