Glissandi on the trumpet are kind of a mixed bag. On one hand, the trumpet can produce the super cool falls and doits that are familiar from jazz music. On the other hand, it’s nearly impossible to produce a pure glissando over intervals larger than a semi-tone. In any case, there are several possibilities for producing glissandi on the trumpet. Since each technique produces different results, the composer may want to specify which technique is preferred.
A chromatic glissando uses all (or most) of the tones in between the starting note and the end note. For the player this is generally easy and requires no new techniques. Chromatic glissandi can be used for intervals of a major second or larger. Depending on the time given for a glissando and the size of the interval, the player may play all or just some of the notes in between. The glissando can either be written out or implied with a glissando line. If the glissando is not written out, ‘chrom.’ or ‘chromatic’ should be added above the glissando line for clarity.
The first and third valve slides can be used to produce ‘pure’ glissandi with no breaks. This is, however, only possible for intervals of about a minor-second or smaller. These small glissandi are possible on almost all minor-second intervals on the trumpet, though an alternate fingering is almost always needed on one or both of the notes. In the example below, G (which is usually played open) is played with 2nd and 3rd valve (the fingering for Ab) with the 3rd valve slide extended, allowing for a clean glissando up to the Ab. For the few intervals not possible with this technique, half-valve glissandi or bending the pitch with the embouchure (see below) is recommended.
Special Considerations: The slides used for slide glissandi are manipulated with the left hand, which can hinder other techniques that use the left hand (microtonal playing, mute manipulation), so make sure you only use one of these techniques at a time!
Slide Glissandi with Quarter Tones
Slide glissandi over intervals larger than a quarter tone that begin or end on a quarter tone are generally only possible in the higher register. This is due to the fact that most quarter tone playing already requires adjustment of one or both valve slides, leaving little room for slide glissandi. Quarter tones in the high register that use the 7th overtone (and 1st or 3rd valves) are an exception to this rule.
There are also some alternate fingerings in lower registers that would allow for small glissandi starting or ending on quarter tones. If you are planning to make extensive use of this technique it may be worth considering using a trumpet with a quarter tone valve. Definitely check out my post on microtones to learn more!
Half-valve glissandi can generally be used for all intervals. This is the most flexible of all glissando techniques and is also very simple to produce (see my post on Half-Valve technique). If no other indication is given for a glissando, this is the technique I would probably use for intervals larger than a semi-tone.
The half-valve sound is noticeably different than the normal trumpet sound, giving the glissando a particular color. Different half-valve combinations can be used for the same glissando, allowing the player to choose whichever is the most effective. Generally the half-valve glissando is ‘semi-pure,’ meaning some harmonic breaks may occur if the interval spans several overtones. ‘Half-Valve’ or ‘HV’ can be written above the glissando for clarity or explained in a legend.
A player can also ‘bend’ a given pitch up or down using the embouchure alone. In the low and pedal registers the pitch can be bent up or down quite far; in the middle register pitches can generally be bent down about a whole step; and in the high register most players can only bend pitches a half step. Bending upwards is not so easy in the middle and high register, this is generally only used for intonation correction. When bending pitches, much of the sound quality and resonance is lost and the goal pitch will have a different sound quality from the starting pitch.
Glissandi in the low and pedal registers are made easy by bending, though pitch accuracy will become more difficult (be sure to see my post on pedals).
A glissando that is unique to brass instruments is created using the natural overtones of the trumpet. As long as there are available overtones in between the starting and end pitches, the direction can be up or down. The more overtones available in between, the better it sounds!
For some intervals it may be most practical to combine glissando techniques to produce the best result. This is perhaps less important for composers to notate, but good to know that it is possible. For larger intervals the most common combination is overtone and half-valve. This produces a fairly clean sounding glissando with less gaps.
For smaller intervals, like a major 2nd, I would tend to combine half-valve with slide glissandi. In the example below I can start the glissando very cleanly to give the illusion of a pure glissando and gloss over any gaps with half-valve.
With all those choices, you might be a bit uncertain about writing glissandi for the trumpet. My advice is to just go ahead and write them! Just keep in mind that they might not always sound as clean as you imagine. As always, its best to seek out a player who can try your music in context and help you find the best solution.