Brass playing is much more physical than sometimes believed to be. As in any physical endeavor, a constructive preparation of warm-up should be truly beneficial. Not only does it enable us to become properly attuned physically, but probably more important, it assists us mentally, in that it motivates. That is to say, it gives impetus, direction, and is a precise launching pad to get a practice session off the ground, so to speak. Many well intended practice sessions may grind to a halt because of a lack of direction or a plan. If the "warm-up" does nothing else, other than providing those important, initial guide posts, its function is highly important. Without a beginning, how can there be a middle and an end?
For now, let us assume all this is true, and examine what a "warm-up" session might consist of. Let me hasten to add that these are only my own ideas, and no gospel is intended.
While there may be a great deal of proper material in print to assist us in the correct warm-up, properly assembling and assimilating said material is the main problem. Most advanced players have their own system, most of which bear a striking resemblance. What we are concerned with is the trumpet player who is still searching for his own system. The following represents what I use.
It seems to me that a warm-up session could and should well be a complete practice session in its own right, in that it contains the basic fundamentals of brass playing. Let us start with long tones. I accept and adhere to the use of long tones because such great brass players as Herbert L Clarke and Tommy Dorsey both assured me of their validity. Of course they serve to "set" the embouchure immediately and strengthen it, as well as demanding the proper flow of air; as well as vitalizing the lips. Example One is an illustration of the long tone series I use. Bear in mind, they should be played as musically as possible. The entire warm-up should be as musical as we can make it, hence, more enjoyable. In Example Two, I have indicated the type of lip slurs with which I follow up the long tones. It is very important to be cognizant of the indicated syllable markings, and remember the importance, also, of a very continuous air flow. The third part of my warm-up is the use of Clarke's technical studies. It is important to play these as slowly as we must to play them without mistakes, and to play them evenly. In order to do this, you must, and I emphasize this, "Bang those valves down"! In this case, speed, facility, and artistry are born of the willingness to put in some very laborious and painstaking work.
In looking back upon my remarks, I would like to add that previous to the long tones, and as a beginning, the principle of mouthpiece buzzing, done briefly, may be very helpful in energizing the lips. I feel, also, that it is tremendously important to warm up our breathing apparatus in some way, by anything even as elemental as taking a deep breath, holding it for 15 to 20 seconds, then forcefully exhaling it by pushing in with the stomach muscles. Also very important, although I may be challenged vigorously on this point, is to "warm up our thinking" - that is, to harness and focus our mental powers or more simply, wake up our powers of concentration. Every action in playing is preceded by a thought.
Yes, the warm-up is fine, but what we really need is the complete practice session. If the warm-up points us in this direction, we can certainly find the road. If we are to elevate and strengthen the fraternity of those who believe in good music, we must declare ourselves and seek inspiration from within and without.