There is a free DeClicker plugin for Audacity which will automatically remove clicks, here.
Now the bad news, that plugin is slow: at the settings required, (shown above), processing-time is about double the playback-time , (on my computer, YMMV). Also that plugin may choke on audio which is hours long, you’ll have to apply it in installments, (Try 15 minute chunks, then see if you can get away with longer sections).
The code below if put into Nyquist prompt removes the mains-hum, (no effect on clicks)
That’s 60Hz mains-hum and some other constant low-frequency signals, (and combinations thereof).
You can get rid of them with the notch-filter code shown in my previous post.
Paste the code into Audacity’s Nyquist Prompt, (which is in the effects menu),
then apply Nyquist Prompt to the Audio like any other Audacity effect.
If you still hear rumble after removing the hum, try this “100Hz rumble” filter in Audacity’s equalizer.
Great plug-ins. I echo all the other congratulations.
You changed three things from the defaults - interesting, could you say your thinking?
Step size changed from 5 ms to 3 ms.
Minimum time between clicks (steps) changed from 3 to 2.
Test frequency minimum changed from 150 Hz to 5000 Hz.
You’ve also changed the test frequency maximum from 9600 to 15000, but think I understand that: although few can hear above 9600, why not be thorough, since high frequencies don’t take as much computing time as low frequencies.
Can I also ask your opinion on the order of processing? From experimenting, it seems to me the following is the right order, but being new to all this, I am not sure:
Run 100Hz rumble first, because that fixes the “p” pop plosives sounds. And because if I don’t run it first, there are some big spikes in the audio that reduce the effectiveness of the following normalization step.
Run normalization, making the audio clips much louder (and better).
Run the DeClicker.
I do not run compression, as to my untrained ear it distorts the emphasis I try for in the audio. Does this seem like a sensible choice (if not, it would be great to get your input as to why)?