Capo 1.0.2 enables you to slow down songs dragged from iTunes, without affecting pitch, so you can easily hear the notes and learn how they're played.

The app isn't alone in its field, but it betters Amazing Slow Downer and Transcribe by way of a stunning user interface.

A single window houses album art, a timer detailing your location in the song, speed and pitch controls, the waveform and playhead, as well as volume and playback controls. Attention to detail is stunning. For example, playback speed can be snapped to one of five presets, but a slider accessed via a mouseover enables you to choose values in-between.

Pitch controls work similarly. Smaller increments are used for matching tuning and larger ones for changing key. In the waveform area, you can drop markers, which come in verse, chorus and bridge varieties, and if you find a particular part of a song tricky, loop it via a drag-selection and click.

Capo's useful touches soon become apparent: the vertical bars in the scrollbar that represent markers; the keyboard shortcuts; and separate play/pause toggles for playback and playing a selected loop.

Aside, from a lack of song and loop export, Capo has no negatives, and while one might argue for extra features such as note-taking, we'd happily forego those for the solid and refined experience on offer.

Follow TechRadar Reviews on Twitter: http://twitter.com/techradarreview