Vinyl Audio Restoration using Wave Corrector Overview of Audio Restoration Vinyl is a relatively delicate medium which is easily damaged by the presence of dust and grit which becomes embedded in the record groove during normal play. A disc can also become damaged by the careless lowering of the stylus or by other hard objects. All these types of damage cause so-called impulsive noise disturbances which produce sounds ranging from tiny high frequency ticks to loud unpleasant clicks and plops. Particularly annoying are the repeating clicks which occur when the damage has spanned several adjacent record grooves and which consequently repeat once per revolution of the record. Audio restoration is the name given to the process of removing these disturbances and reconstituting the original waveform.
Audio restoration is a two stage process.
Initially the wave file is scanned using an algorithm which discriminates between wanted musical content and unwanted noise. This is a far from trivial task because some musical instruments, especially low frequency brass and reed instruments, have waveforms remarkably similar to typical clicks. The waveform can be analysed in either the time domain, the frequency domain, or a combination of the two. Generally speaking, the goal is to identify instantaneous deviations in the data which are statistically significant. These outlier events are usually indicative of an impulsive noise spike.