Best posts made by Libertydoc

@_mark_ Mark, I would say you are approaching a topic that is worth learning even in the beginning. You are correct, the pedal tones are those that are not fundamentally on the horn. Learning to play them will enhance your breathing ability and control of your embouchure; both are items you will need for the upper register.
The easiest way I know of to learn a pedal is to start by playing the F# at the bottom of the trumpet range. Then, once you have the tone, bend it flat. This will involve relaxation of your embouchure, jaw and lips as you want the lips to flop at a lower frequency that needed at the higher registers. You'll find pedals take a lot of air! For the beginning, you can use the same fingerings as you would for the notes in the octave above. You will find you'll be using more lower lip as you go lower. My lowest range (which took a while) is the double pedal C and feels like it is almost all lower lip.
Pedals will likely never sound crisp and clear like the other notes on the horn and, like everything else, they take practice. Pedals are a great way to warm up (read Carmine Caruso books) and the learning books Total Range by Charles S. Peters and Systemic Approach to Daily Practice by Claude Gordon include pedals in the initial lessons. Have fun with them! They are worth your time.