Compressing Pitch Range

• Nov 26, 2020 - 19:03

In this example the black notes are 1 octave lower than the blue, and the red notes are 1 octave higher than the blue. So the blue are half way in pitch between the black and red. I want to compress this (piano) range to arrange for guitar.

If I drop the the red notes by 1 octave is there any way to transpose the blue notes down so that they remain half way in pitch and still sound right? I tried dropping them all by six semitones, (i.e. half an ocatve), but they sounded wrong - out of tune.


(I realise that, as it stands, these notes are all easily playable on guitar but there is a bass voice to incorporate too and this would make the stretches too large.)

Attachment Size
octavecomp.png 12.48 KB


You wrote: there any way to transpose the blue notes down so that they remain half way in pitch and still sound right?

It depends on what you mean by "sound right".
Generally speaking, notes an octave apart are musically equivalent. Ever notice when in mixed groups, men and women tend to sing "Happy Birthday" an octave apart? Even though they are not singing in 'perfect' unison, the song still "sounds right", yes? So, if one group suddenly stops singing, the melody still carries on and sounds right (if only in a higher or lower octave).

Now, if some decided to sing notes found in between the octave, they are creating harmony - which may still "sound right" if the chosen notes are harmonically pleasing (sung as part of the whole). However, listening to that harmony part all by itself may not "sound right" when compared to the original melody line. (Think of the various parts in barbershop quartet harmony.)

If you are arranging a melody for solo guitar (where you are playing melody + bass with chordal harmonies), one technique is to use octave changes at the beginning or ending of melodic phrases. This can even add musical interest to an otherwise mundane tune.

Another technique is to transpose the whole piece into a key that puts the melody notes on, say, the first three stings while also taking advantage of open strings, especially for bass notes.

Regarding your specific example, there is no "octave equivalence" existing between the black-blue or between the blue-red notes. If you drop the red notes an octave they become the blue notes. Dropping the blue notes an octave makes them the same as the black notes.

In reply to by Jm6stringer

Thanks for this. I did try a variety of transpositions and most of them clashed with the other notes. I have transposed the original to make use of open strings but am still left with a large piano pitch range to accommodate – hence my idea of the blue notes.

All the notes shown are part of the melody so that's probably why I'm struggling. I'll have a play with some octave changes. I might be able to put the melody on the top 3 strings at the expense of some barre chords to keep the bass notes reachable.

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