Vibrato is a slight oscillation or, put more simply, wobble in pitch. A good way to visualise it is to think of the left hand of a violinist, which moves rapidly in order to produce this sound:
Why is it used?
It is way of adding expressivity to music. In some circumstances a note played 'straight' can sound too cold. We use vibrato to produce a warmer, more emotional sound.
How do I play with vibrato?
There are three ways of achieving a vibrato sound on the trombone:
This method of vibrato is unique to the trombone, since it relies upon the mechanical movement of the trombone slide. Some of the greatest exponents of this type of playing come from the big band/jazz school of trombone playing,
such as Bill Watrose, David Steinmeyer, Don Lusher and, perhaps above all, Tommy Dorsey. Listen and watch Dorsey as he plays some of the longer notes in this solo; you will see his
slide moving rapidly backwards and forwards and hear the pitch 'wobble' around a central pitch.
Slide vibrato then is best suited for jazz/big band repertoire, though it can be used in classical works, especially where there is a sentimental or jazz element.
Before playing any type of vibrato, it is important that you can produce a good rounded sound in all registers. Vibrato should be considered as the 'icing on the cake',
an extra layer of expression that will take you playing sound to the next level. It should never be used to hide problems with your sound. To play the slide vibrato practice playing scales with long notes with a good rounded sound:
Now, making sure that you hold the brace of the slide lightly, try adding slide vibrato with a forwards and backwards movement around the original pitch, as demonstrated by Jiggs Whigham:
The pitch of the note must be in the centre of the vibrato, otherwise your playing will sound out of tune (this also applies to jaw vibrato, see below).
The motion of the slide comes principally from the hand and wrist and not so much from the arm, otherwise the rest of the instrument will move, at the same time affecting your embouchure
and the quality of sound. Bill Watrous demonstrates:
2. Jaw vibrato
This type of vibrato is sometimes also called 'lip vibrato', though it principally uses the jaw. Subtler than slide vibrato it especially suits classical playing,
even though it is also in other styles. Practise the scale again with a straight but fully rounded sound.
Now, play again, but this time add the vibrato by moving the jaw as if you were saying 'wah-wah-wah-wah...'. Don't actually try to say it! Only the jaw movement itself is required.
Start each note without the vibrato and then experiment by adding the jaw motion. Jonathan Randazzo demonstrates:
3. Diaphragm vibrato
This is also sometimes referred to as 'flute' vibrato, being the most common method of producing vibrato on that instrument. As the name suggests, it is produced by altering the flow of air from the diaphragm.
Instead of releasing the air with one long 'haaaa' sound, it is released as a 'ha ha ha' sound.
It is fair to say that this is probably the least commonly used vibrato on brass instruments, with many saying that it produces less pleasing results and, especially, has the additional danger of weakening the airflow. Nevertheless, some great players, such as trumpeter Roger Voisin (Boston Symphony Orchestra 1935-1973), have used it.
You should probably, however, concentrate on learning the first two methods.
When should I use it?
Even harder than learning how to produce a good vibrato is knowing when to use it properly. Here are a few tips, however:
Unlike a string section, where all of the individual players vibrato at the same time, you will probably not use this type of vibrato when playing in larger ensembles. There will always be contexts where the opposite is true, but in this situation, if in doubt, don't.
Conversely smaller ensembles, where there is more of a solo element will allow you to use vibrato more freely.
Solos. Go for it! The mark of a truly great soloist is in his or her use of a beautiful vibrato.
Performance practice. Some repertoire traditional demands a different approach to vibrato. Baroque music, for example, will use vibrato rather sparingly. If you are playing jazz or Mariachi music, however, the vibrato will be often and wide.
The musical mood. Quiet and/or expressive music is often especially suited to vibrato. Loud and majestic music can sometimes sound coarse if there is too much vibrato.
Personal style and sensibility. This is where we truly get into the artistic part of trombone playing. The truth is, in any given situation there is often no exact rule as to how wide or fast your
vibrato should be or whether you should use it all. You must decide. The only way to truly master vibrato is through experience and through listening to many great players.