11. De-noising and other restoration tools

During the processes of recording and mixing, many things can end up in the mix that you'd rather not have in there. Artifacts like noise, humming, cracks, distortion or too much ambience—the list of possible technical flaws is long. While it is completely feasible to try to eliminate grid hum with narrow-band filters at 50 Hz, 100 Hz and so on, to keep noise in check by using a high cut filter, and to „erase“ cracks manually by editing the audio waveform, there is a range of specialised tools for these tasks that tend to provide the best results.

iZotope RX visualises short disturbances like cracks or coughing as bright dots. They can simply be „retouched“, similarly to photo editing software.

De-Hum, De-Crackle, De-Noise and similar plug-ins and devices do a very reliable job these days, without causing too much harm to the audio signal. There are de-noising tools that can take a „fingerprint“ or snapshot of the noise and subsequently reduce it. The transition from simple „first aid“ during mastering to full-fledged audio restoration is seamless. The quality of today's restoration tools is such that formerly „broken“ material can now make its way onto the commercial market and leave the listener completely unsuspecting of the effort that went into restoring it.