Transposing, notated on one system in treble clef.
As a rule the mallet-played glockenspiel sounds two octaves higher than written. However, notation in many scores is only one octave lower (e.g. in Richard Wagner).
There is often no indication in the score of whether the notation is one or two octaves lower than the sound. In such cases the musician must take the register and range of the passages as a guide.
A transposing instrument notated on two systems both written in treble clef.
The keyboard glockenspiel generally sounds one octave higher than written.