The pedal exercise on the leadpipe
After playing on the B.E.R.P. you will have experienced a lot of resistance.
To loosen up here is an exercise that uses an idea from Jerome Callets book "Trumpet Yoga" and combines this with a Bill Adam routine, playing it only on the leadpipe.
By playing it only on the leadpipe you will get less resistance than on the trumpet and the glissando will be easier to perform.
Take the tuning slide out of the trumpet and play only on the leadpipe. The sounding note will be close to an F (or an concert Eb) on the Bb trumpet.
Start from this F and slide down two octaves to double pedal F. When reaching the low F the lower lip should be very protruding and most of the mouthpiece placed on the upper lip. Try to make the low sound very strong.
Then go one half step down to E and slide down to double pedal E. Continue down to low C and slide down to double pedal C.
Repeat this exercise, but this time also ascend back to the starting note.
It helps to use the valves to assist in focusing each "pitch". Valve 1 down on the F-glissando, valve 1 & 2 on the E-glissando, etc.
Consider this routine a very exaggerated movement of the embouchure.When using this routine, the feel you will begin to get is what Callet calls "the fat feel".