To fully appreciate the difference in bass lines, and therefore the 'sounds' of a style, just pick a style - one I tried was 'Bossanova' - and mute all but the bass accompaniment ... play CM, then slide up to Dmin7 (DFAC) then Emin7 (EGBD), then F6 (FACD) ... there will be a noticeable difference between the Dm7 bass line and the F6 bass line ... you can also just play the Dm7 and then the F6 to make it simple ...
When playing with the "On bass" option, you can get nice voicings for certain songs, for example "This Masquerade" by George Benson ... when using the 'On Bass', the bass note will be the leftmost note you are playing in the chord - starting with the Cm (C Eb G) and then playing a CmM7 (B C Eb G), then Cm7 (Bb C Eb G), then playing Cm/A (A C Eb G), (this chord shows on the screen as an Amb5) - then playing the AbM chord (Ab C Eb) produces a nice descending bass line for the tune ...
This may take some getting used to, but it does add a nice 'flavor' to the tune ...
Hope this didn't confuse the issue ...
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t.