Many brass players have problems playing smooth legato lines and keeping the air flow going. This little exercise will help you overcome those issues, and it is also a comfortable mouthpiece warm up. The goal is to let the air flow freely and without interruptions when you change notes, regardless if you play glissando or legato. When playing staccato you will have to stop the airflow between notes, focusing on not building up any tensions or changing the embouchure. PLaying in pitch on mouthpiece can be hard, and doing it while playing staccato is really hard, so focus on that too. When you can play a staccato melody in perfect pitch on the mouthpiece, you probably can not play out of tune on the trombone!
Checklist for this exercise (and many other):
1. Inhale and exhale freely
2. Smooth attack and same dynamics on all notes
3. The only difference between glissando and legato is a very small, rapid tongue movement!!!
4. Make sure that your tongueing is as discreet as possible. I like to compare it to rapidly moving your finger through water pouring out of a water tap. This is what your tongue should do with the airstream!
5. Only use the tongue to help control the attack – do not build up air pressure behind the tongue before the attack.
6. Pitch, pitch and pitch. Don´t give up if it feels impossible to play the staccato part in pitch in the beginning.
7. Relax! If you have to put up a fight to make a sound on the mouthpiece, you either got concrete instead of botox at your last treatment, or your airflow is not totally in place. You will know which condition applies best to you.
I recommend that you start this exercise in a comfortable mid range (around F or D below keyhole C), and work your way both up and down by half steps. Sheet music and sample audio of the exercise below!