Re: Percussion and tab clefs question

[Noeck]

Dear Jacques,

I guess the pitches are undefined in both the tab clef and the
percussion clef.

The tab clef only makes sense on a tab-staff where the notes are denoted
with numbers (frets) per string.
The percussion clef might have some pitched instruments, but there is no
universal definition (to my knowledge).

Finale seems to use positions like in a treble clef for both the tab and
the percussion clef. Which is understandable as it is the closest to a
default clef.

LilyPond seems to use an alto clef positions for both – which I don't
understand why this would be beneficial.

{
  c'2 e'
  \clef bass
  c'2 e'
  \clef tab
  c'2 e'
  \clef percussion
  c'2 e'
  \clef alto
  c'2 e'
}

HTH,
Joram