The following question came in over email:
Does HOOKPAD contain voice-leading rules?
What rules exactly?
When I make a chord-progression, sometimes it makes parallel movements
For example:
in the key of C MAJOR:
C to dm chord
How do you know when an inversion is needed, and which one? 1st,2nd,3rd?
(because of voice-leading rules)
Hookpad does not explicitly avoid parallel movements in its voicing algorithms.
In general, when composing popular music, many of the rules that you are taught in a classical harmony course can be somewhat relaxed. For example, we are taught in school that parallel 5ths are to be avoided at all costs. However, many popular songs get away with parallel 5ths, and listeners don’t seem to know/care.
For example, a chorale that is properly voiced in the classical sense would tend to avoid a progression like: I → ii (C → dm), since it is difficult to avoid a parallel motion. One solution would be to invert the ii chord: I → ii6 (C Dm/F), or I → ii64 (C → Dm/A). Which inversion you choose depends on where you want your progression to go, and more importantly, which sound you like better.
However, in popular music, I → ii is actually a pretty common progression (in fact, it happens 3287 times according to the TheoryTab database). If you are particularly worried about the parallel motion on the right hand of a piano accompaniment, I would recommend voicing the chord with the 3rd or the root at the top of the chord as opposed to the 5th (generally these voicings sound much better during a parallel motion).
As we discuss in the inversions chapter of our book, Hooktheory I, some inversions (like ii6) are much more common in classical music than they are in pop. The most common inverted chords we see in pop are: V6, I6, IV6, I64 and more recently iii64 (which functions like a V6).
If Hookpad’s automatic voicing of a specific progression irks you, you can always make small adjustments to the range of the voicing algorithm using the octave slider in the mix tool.