|This is a small collection of tips about audio restoration tasks for which it could sometimes be useful to use software other than Audacity (even though you might use Audacity for most of your audio creation and editing).
The following are standalone applications which can remove steady noise and clicks and pops, as an alternative to using Audacity's Click Removal and Noise Reduction. These are mostly specialised applications targeted to restoration of gramophone records, but can be used to restore other noisy sources. They are free, open source unless stated otherwise. Export the sound file you want to restore as a WAV or AIFF file from Audacity so that these applications have a lossless copy of the audio to work with.
There is workflow tutorial here in the Audacity Manual concerning the whole subject of transferring records to CD, including useful tips regarding the preparation of LPs for transfer and cleaning up of the recorded audio.
Windows, OS X and Linux*
Shareware application for removal of click, crackle and localised noise. Although automatic, every single click removal can be individually customised. Frequently recommended by Audacity users. Can be set up for batch processing of files for repair.
Note that the application requires Java to be installed in order to run.
GUI application including noise reduction, click/pop reduction and interpolation, very easy to use but beware overwrites source wav file!
Although nominally shareware, in effect this is a top class, free pop/click and noise remover as well as an excellent alternative audio editor. Its click and noise reduction are effects, just like in Audacity. The trial version limits you to a hundred or so commands per session, and a total number of several thousand commands before it expires, but if you export from Audacity as 32 bit WAV and just do Click Removal in it, you should be able to do several hundred records for free.
Linux/Unix and Windows
Performs click removal from audio files recorded from vinyl records. Primitive interface (only runs in a DOS window on Windows) but filters are very configurable. Windows version only accepts 44100 Hz stereo WAVs as input.