Believe it or not, ‘playing style’ is extremely important to Sideman. Your playing style is what Sideman analyzes in order to generate accompaniment. Imagine you are listening to your favorite pianist (mine happens to be Bill Evans and Oscar Peterson). What exactly do you hear? Here are some things I try to pick out:
- What Key Signature is the performance in? Does the performance modulate between different Key Signatures?
- What are the chord changes? In a specific key I tend to hear I, II, II, IV, V, VI and VII chords.
- Is the performer ‘vamping‘ between a small set of chords? For example II min7 <-> VSus11.
- Is the performer simply ‘comping‘ through a set of chords, as would be the case if he were ‘backing up’ a vocalist?
- Is the performer ‘soloing’ over a set of chords? If so, is he playing ‘modal scales’.
- How ‘aggressive’ is the solo? Notes per bar and volume are factors in this.
- Is the performer playing a Bass pattern?
- Is the performer playing at a specific ‘tempo‘, or is he simply ‘improvising’ with no apparent tempo.
- What type of ‘chord voicings‘ are being used: ‘crushed’ block chords, ‘open-voice’ chords spanning several octaves, etc.
- Are ‘rootless chords‘ being played, where the chord root is either implied or meant to be played by a bass player.
- Does the performance ‘swing’? Does the performance have a ‘hip-hop’ feel, or perhaps a ‘Latin feel’?
- What volume is the pianist playing at? Are chords played ‘staccato’?
These are the type of musical nuances that Sideman quantifies in order to guide the accompaniment.
For example, if you simply play in an ‘impromptu’ fashion, with no strict tempo or key signature, Sideman can at most infer only a general sense of what chords are in play. Examining a set of notes being played, Sideman might determine an implied ‘chord root’ (perhaps the lowest note being played), whether a major third or minor third is present, whether a ‘tritone’ is present, etc. From just this information, Sideman might generate a string accompaniment that follows one of the notes being played. A set of chords might contain a common note that is consistent throughout those chords, which provides an excellent note to be played as a Sting note.
On the other hand, the performance might be played at a strict tempo and time signature (think 8-beat, 16-beat, 6/8 beat, swing beat, etc). In this case, Sideman has no difficulty determining the tempo, time signature, and song style.
If the performance is done with a wide range of volumes, Sideman can track these volume changes and adjust the accompaniment volume accordingly. If the user pauses his playing, Sideman can pause the accompaniment and resume as soon as the pianist resumes playing. When the performance ends, it might consist of a sustained ‘ending chord’. Sideman can detect this and generate some ‘ending accompaniment’ that might be little more than an arpeggio of the ending chord, played by violins. You can see how important your playing style is – it is the ‘input’ to sideman’s algorithms that generate accompaniment.