Ah yes, the bane of the amateur musician (like myself) – solo ‘modes’. Your band composes a ditty with chords of Dm Bb C and G major and expect something from you that’s improvised and vaguely in the right key, something that fits in. But for any non-trivial song, how do you make sure that the notes you experiment with fit the modulating key(s) within the chord structure? If you’re Eric Clapton then you’ll find the right notes without thinking. For the rest of us, there’s Solo Finder on the iPhone.

The main screen is intuitive enough, once you work out what the terminology means – you’ll need a smattering of musical knowledge already, of course. But then you already play, don’t you? Fourteen different variations on each chord (major, minor, major 7ths, etc.) and up to four chords for the aforementioned sequence mean that most song segments can be represented here. When you’re done, tap on ‘Calculate’ and, within a fraction of a second, the maths is done and an appropriate solo scale selected.

Of course, it’s still down to your ear as to which note in the suggested scale you play at which point in time (and under which actual chord), but at least you’ve got a starting point and will hopefully play less obviously ‘wrong’ notes. The suggested scales are named (e.g. ‘G Major’, ‘Ab Harmonic Minor’, ‘F Heptatonic Blues’ and the wonderfully named ‘Hungarian Gypsy’), which may help, and the fingerings shown on guitar, bass and keyboard. These eventually make sense, but the fretboard diagrams are initially misleading because the ‘nut’ positions (where the strings are fretted by the bar at the end of the fretboard) are shown as normal finger positions – a solid (thick) line would have been more conventional here.

If you’re learning your trade on any of these instruments, this little utility could prove very useful – just allow a little time to translate the graphics shown into physical finger positions on your instrument. As you’ll gather from chord names like ‘Eb7#5′, music theory can get seriously complicated!