I have those strange buttons in my keyboard so I was wondering what are they for ? When I press on one of them, the leftmost notes output weird sounds whenever I play them I can't understand ??

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    Reading the instructions should tell you! But I guess it's something to do with left hand chord playing. Normal means you can play several notes as in a proper chord. Fingered probably means if you press one note, the keyboard makes the rest of the chord up for you. By pressing two or more notes, you're confusing it. Make and model would help.
    – Tim
    Commented Apr 27, 2021 at 11:05
  • Hm ok thanks. Btw I lost the instructions that's why I am asking here Commented Apr 27, 2021 at 15:40
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    Usually instructions are available to download from the 'net.
    – Tim
    Commented Apr 27, 2021 at 15:49

1 Answer 1


I don't know what keyboard that is, but that looks like the control for the ABC [Auto Bass Chord] system [That's a Yamaha term, other manufacturers may call it something else, but they all do a similar job]. Basically, it's a chord recognition mode.

  • When set to Normal, the ABC system is off.
    Whatever notes you play, that's what you will hear.

  • Fingered applies 'complex' ABC.
    If you play C, E, G, B it will play accompaniment in CMaj7
    C, E♭, G it will play Cmin, etc.
    Some of these are pretty clever & can differentiate between, say, C6 & Amin7 depending on how you voice your chord. Some can't. Some can recognise right up to a 13th chord. Some can't. Some can make musical sense out of complex chords, for instance by applying priorities to root & 5th, 'flavour' notes below & above the octave etc… Some can't.*

  • S. Finger is Single Finger, 'simple' ABC.
    In this mode, pressing C will play CMaj.
    [This is where manufacturers may differ]
    Pressing C & B will play Cmin.
    Pressing C & B♭ will play C7
    Chord recognition in this mode is necessarily limited to just a few types.

*Some of you may already know I used to make these accompaniments for a living. I am still under NDA & not at liberty to divulge just how this is all calculated. Sorry.

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    Do you ever recognize any of your work on John Shuttleworth? Commented Apr 27, 2021 at 12:02
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    HaHa;)) In fact, his 2 main keyboards almost pre-date me. I was there 90-2000. I had to look up what he uses - soundonsound.com/people/graham-fellows-aka-john-shuttleworth - & they're from 88 & 92. Both low-end. I used to work on the high end stuff which was then hacked down to fit the low-end, so there might be something in the PSS 680 cut down from ones I made the year before, but it's so long ago I wouldn't recognise them any more. First one I worked on was I think PSR-6700 [or 4700], last was Tyros. The PSS series was another division, but they re-used last year's PSR data.
    – Tetsujin
    Commented Apr 27, 2021 at 12:19
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    Excellent! :) Apparently the PSS 680 is the Austin Ambassador Y-Reg of keyboards then..? All useful info as I endeavor to model my life on John's as closely as possible... Commented Apr 27, 2021 at 13:14
  • "S. Finger (...) Pressing C & B will play Cmin. Pressing C & B♭ will play C7" → Depends on the model. CASIO keyboards also have this functionality, but it is based on lowest key + number of keys pressed. Pressing 1 key will give you a major chord, pressing any 2 keys gives a minor chord, pressing 3 gives a maj7, and pressing 4 a min7. The lowest key pressed will be used as the tonic. It doesn't matter if keys are consecutive or not, i.e. pressing C2 and D2 is the same as pressing C1 and E2: two keys pressed → lowest is a C → Cmaj chord. Source: owned a CASIO CTK for several years.
    – walen
    Commented Apr 28, 2021 at 9:00
  • Yeah, I imagined different manufacturers would have different rules for this. It's one of those things the OP will have to check the manual for, to check how it's implemented. [I may in fact have the Yamaha rule upside down, it might be the bottom note that determines it - it's been far too long since I last used anything like this ;) I can't even test on the old keyboards I still have - they're so old the backup ROMs have died, so there are no styles left to play [this is true of all the keyboards I have of that age, they're 'empty' of all but the voice sounds.]
    – Tetsujin
    Commented Apr 28, 2021 at 9:08

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