There are two main techniques of producing a glissando (a directional slide of pitch) on the tuba—changing lip embouchure and shifting slides—of which the former is far more traditional than the latter. It is also possible to traverse the overtone series through a fast slurring of partials in what is called a harmonic glissando.
Range. As a rule of thumb, approximately one semitone, though this decreases as partials get closer together. Once partials are less than a semitone apart, the instrument will jump to the next partial before the full semitone of gliss is achieved. Conversely, in lower registers, it can become possible to gliss downward beyond a semitone (in extreme cases, as much as a minor third). In general, downward glissing is easier than upward. It should be noted that glissing to, or even near, the limits of range in a given register risks a sudden, unpredictable jump to the next partial or a split tone.
Range. Approximately one semitone. This option does not carry the risk of partial jumping and does offer a certain precision through visual reference, but it also requires the time and capacity for a physical shift of hardware. Depending on the horn, it is often the case that from its “tuned” position a slide will only produce a pronounced gliss when pulled out, that is for a downward gliss. Pushing the slide in may only create a very slight variation in pitch. Once lowered, the tone can of course return up to the default pitch, but the slide will not allow for moving beyond it.
A harmonic glissando is performed by changing embouchure and degree of overblowing while maintaining a single fingering in order to cycle quickly through the partials of a harmonic series. Cascades from high to low are generally easier to perform and potentially more dramatic in quality than ascensions from low to high, though both can be effective. A few particulars: It is possible to begin and/or end a harmonic glissando on precise pitches. It is also possible to change direction (pivot) mid-glissando. This can be done to a relatively virtuosic degree of speed/density. Further, it is possible to change the fingered series mid-glissando without being noticed. And finally, because partials are closer together in the higher register, cycling through them will produce a clearer sense of glissando than their lower counterparts.
Pitch range. Same as ordinario.
Dynamic range. Same as ordinario.
Maximum speed. Up to the where individual partials blur together; 12 per second and faster.