Audio restoration is a process used to reduce noise such as hiss, crackle, hum, etc. from audio recordings. Most modern techniques of audio restoration are performed in the digital realm on audio from an analogue source. The removal of unwanted sounds is usually performed in DAWs (Digital Audio Workstations) however there are also digital standalone de-clicker's, de-noiser's and dialogue noise suppressors. Although there are automated solutions, audio restoration is still a time consuming and complex process that often requires experienced audio engineers with a background in audio post production.
Record Restoration is a particular kind of audio restoration where the audio is converted from the analogue signal on a gramophone record (either 78, 45 or 33⅓ rpm). First the record is cleaned to remove surface noise that can be caused by dirt, then it is transcribed into the digital realm, where software is used to adjust equalization and volume. This from of audio restoration is however rarely used and gets harder the older the record is, due to the nature of the medium (playback causes gradual degradation of the recordings).