Making audio sound better one square wave at a time
Leif Claesson · 2015
Audio mastering engineers have felt increasing pressure over the years to master recordings at ever increasing loudness levels as compared to other contemporary recordings, by way of dynamic compression, peak limiting, and hard clipping. This pursuit of loudness adds distortion, reduces fidelity and ultimately impairs audio quality. When radio stations play the already compromised audio from contemporary music through their typical FM processing chains, this confluence of degradation causes serious audio quality issues on air. Besides leading to listener fatigue, this can even be mistaken for poor reception by listeners, ultimately causing tune-out. When pre-distorted contemporary recordings are encoded through typical perceptual codecs, the codecs end up wasting bits trying to faithfully encode the distortion components, in lieu of the original audio. This paper shall examine what the music typically endures when broadcast on FM, and how that understanding led to the invention of the “undo” algorithm, which is applicable to both the broadcasting and recording industries, and automatically repairs some or most of the damage caused by these mastering techniques by adaptively de-clipping and de-compressing the mastered recordings.Insert abstract text.