Xylophone IS a transposing instrument : not reflected when swapping to Concert pitch

I'll be happy to help

Sorry it took so long,
here is a comprehensive post about orchestral mallet percussion instruments.

See the attached file for transposition information.
NOT FOUND: 1

You can double-check with other sources if you wish, but I already took the chance to check at a rehearsal break last week, with marimba, vibes and xylophone all in the same room. To be 600% sure...

Some mallet instruments exist in different sizes. Therefore, I have a secondary suggestion : one could turn the automatic coloring of notes (red indicating "out of range", green indicating "playable by experienced players") into a maybe useful advice to arrangers, by defining red as "out of maximal range" and green as "obtainable with the extended instrument":

A standard Vibraphone, like the one used in jazz, is 3 octaves from F to F (and sounds as written). But for contemporary music, you can have a 4 octave instrument, from C to C. So, notes outside this 4 octave range should be red, and low C to F and high F to C could be coloured in green, to indicate that these notes might be playable, but drawing attention that it should be clearly indicated that a 4 octave-instrument is needed.

Xylophones sound one octave higher than written. It is a transposing instrument and should be notated in normal treble clef, not the "octava alta" one, because the player just plays what is written on his part and knows the instrument sounds higher. Else, with a 8va clef, a "written in sounding pitches / sons réels" indication would be missing on the performer's part (which would be confusing because the octava clef isn't found that often, and people wouldn't notice it).

What strongly I advise is this :
in "concert pitch", the automatic behaviour should be treble clef with octava sign (sounding correct and written accurately regarding concert pitch)
but outside "concert pitch" mode, a regular treble clef is required, and the instrument is to be played back one octave higher [see Post-Scriptum about saxophones].

Xylophones existed in 3 octaves models, but 3,5 octaves (F-C) is the well-established norm. 4 octaves (c-c) instruments are also available http://www.adams-music.com/pf/products/xylophones/.
Same remark as with the vibes regarding colors.

Glockenspiel (played with mallets, not keyboard – the keyed glockenspiel as a bigger range) exists in many different sizes : Unavailable pitches on a particular instrument, forcing the musician to play some passages at a different octave, can explain the present confusion about how this instrument sounds compared to how it is written. The second reason for this confusion is that some parts written for an extended-range keyed-glockensiel are commonly played on a mallet instrument, causing the need for some further transposition.

The smallest orchestral glockenspiel is 2 octaves, from C to C. The most common Glockenspiel (in a case) are 2.5 octaves (G-C or F-C). Bigger instruments are 3 octaves from C to C, and in order to play accurately the high pitches needed for Debussy, Janacek, Messiaen and others, symphonic orchestras normally use wider range intruments like http://usa.yamaha.com/products/musical-instruments/percussions/orchestr… (3 1/3 octave from C to E) or http://www.marimbas.com/glocks.php or http://www.studio49.de/RoyalPercussion/html/englisch/glocken/glockenspi… or http://www.bergerault.com/products/professional-percussions/glockenspie… .

In written form, I do advise to abbreviate Glockenspiel as "Glsp", avoiding the confusion caused by Glock. (short for Glocken, which would indicate tubular or church bells), even if percussionnists do use "Glock" when they speak.

Official transposition for the Glockenspiel is 2 octaves (see the Grove for example : http://snipurl.com/25gynng ) : It will sound 2 octaves higher than written.

I suggest this behaviour : for legibility reasons, in "concert pitch" mode the glockenspiel should be written using a "15 treble clef", which would change to normal treble clef in the other mode, the transposition making the pitches sounding 2 octaves higher when played back.

Marimba (that I would abbreviate as "Mba") sounds as written, in treble clef or on a "piano staff" when needed. It was 4 octaves at its smallest, then a 4 1/3 marimba (low A) was a standard for some time (and is still widely sold, played and written for), before makers and composers started a trend toward to basses, with low F (or low E in the casse of Musser) instruments, before establishing the 5 octave marimba as a new standard. But, as these low pitches specifically call for a different instrument than the smaller marimba which is still widely found and used, I would advise to set to "green color" the low range, from low C to G#, the "safe standard" beeing a 4 1/3 octave instrument.

As a bonus, and because the instrument is not to be found in today's Musescore list, I shall mention the Xylorimba, or Xylo-marimba. This instrument always causes headaches to performers and orchestra managers because it is not that common in the real world, although composers starting with Messiaen just expected a wooden instrument with an extended range. In this purpose the French maker Bergerault did manufacture a 5 octave marimba, but with the added octave up (not like the modern 5 octave marimba, extended in the bass). See this article http://nexuspercussion.com/2005/06/what-is-a-xylorimba/ (I would agree with the "marimba tuning" for the xylorimba but this is beyond the scope of our matter. Anyway, regarding playback sound if you add the instrument to Musescore, I would simply use a regular Marimba sound).
I would advise to add the Xylorimba to the instruments list, with this standard range : that of a four octave marimba + one octave upwards, sounding as written.

To conclude with an anecdote, when I performed Messiaen's "Sept Haï-kaï" under Pierre boulez, no Xylorimba was available anywhere, and I realised that most of my fellow collegues simply used a marimba and transposed the unavailable pitches (ruining the musical effect of long 16th-notes runs from low to high). I did use a regular marimba as well, but had an extension made with the missing notes by a xylophone maker. Et voilà ! But, at least in Europe you can still find old Bergerault Xylorimbas.

I hope this information is helpful. All the best, and thanks for all your coding efforts.
Sylvain

PS 1 I can't speak for the saxophones players, but the clef behaviour I suggest for the xylophone (8va clef for concert pitch, changed to regular treble clef in "transposing view") would be great also for saxophones : I enter the notes in Concert pitch, and an Octava clef would help prevent ledger lines, while beeing still correct theoritically : Avoiding ledger lines is not only a matter of comfort, making the score more legible, but avoids too much layout changes between the "concert pitch" version of a score and its "transposing" counterpart (with ledger lines one needs for sure a lot of staff spacers, that are unnecessary when turning later to normal view).

PS 2 Bonus : link to an interesting site about Deagan instruments from the XXth century, the Deagan ressource. http://www.deaganresource.com/