Mono-a-Mono removes scratches, distortion (due to wear-and-tear, for example), and tape or surface noise from stereo recordings of mono sources. It can be used to enhance digital recordings of old records (whether 78, 45, or 33 rpm, shellac, acetate or vinyl), audio tapes (reel-to-reel or cassette), or even cylinder recordings, provided only that the playback and digitisation of the signal has been performed in stereo, but the original source was mono.

In its original “mono enhancer” mode, Mono-a-Mono suppresses any signal components which are present only in the left, or only in the right, channel of a stereo recording. Version 2.11 introduced a new “vocal remover” function, which suppresses any components which are common to both left and right channels of a recording.

Mono-a-Mono uses a simple muting algorithm to remove the most obvious clicks, and then filters out the unwanted components using a high-order adaptive linear filter. In this way, almost all the unwanted sounds can be rendered inaudible, and there are very few cases where any noticeable artefacts are introduced.

And yes you’re right; Mono-a-Mono is a rather naff name for a program, but it’s meant as a pun. If “Mano-a-Mano” means “hand-to-hand”, Mono-a-Mono could mean “mono-to-mono”. Forget the fact that “mono” actually means “monkey”. In fact, forget monkeys altogether. Mono-a-Mono, the program, works on sounds recorded in mono, but replayed and digitised in stereo. It then produces a mono output, as close to the original (mono) source as possible. So it starts with a mono signal, via a stereo recording, and ends up as a mono file. Hence “mono-to-mono”.