Harry Berv clearly notes in A Creative Approach to French Horn Playing “THERE MUST BE a warm-up period before the practice session begins.”
A shorter warmup
As noted in prior articles in this series, there is a divide between teachers who advocate for longer and shorter warm-ups. Berv is on the side of the shorter warm-up. He begins by noting that
This warm-up is to be done in gradual stages. Its purpose is to allow all the physical and training aspects of the act of horn playing to awaken and combine gradually….
The F horn should be used extensively in the warm-up session. Its tubing is longer than that of the Bb horn and it requires more air and also makes the embouchure work harder. This strengthens the embouchure and gives it greater flexibility and endurance.
As to how long to warm-up Berv has clear instruction.
One most important rule, not only in the warm-up, but also in the practice session, is this: Do not strain or fatigue the embouchure. This can strain the muscles in the area and set the player back for an indefinite period before they are healed. The warm-up session should have a duration, at most, of ten minutes of actual playing. In this time all the areas involved should be limber enough to cope with any problems encountered in the actual practice session.
More specifically, 15 minutes total
Berv highly recommends long tones as a part of the warm up and a total warm-up of fifteen minutes—“ten minutes of actual playing time interspersed with brief rest periods as needed.” He cautions
If the warm-up session is too long, it will undoubtedly cut down on your endurance. In my opinion, too many players succumb to the idea that the warm-up session should last for a half-hour or more. It becomes fixed in their minds that this is a necessity and feel they cannot function properly without it.
Personal aside: When Farkas told me I warmed up too much
In closing I would offer this personal aside. Years ago in one of my few private lessons with Farkas I described my warm-up to him and he told me that I was warming-up too much. At the time I had a hard time with that advice, it surprised me a bit actually as the warm-up in his book is rather long, and at that point in time I felt that I could not easily change my warm-up. At present however my warm-up is quite a bit more flexible and I realize that the actual warm-up part of the initial routine really is that initial ten to fifteen minutes, similar to that described by Berv. Certainly it is a topic that horn players need to keep evaluating over the years. Especially if you are locked into the very long warm-up it is worth experimenting to figure out something shorter that works for you.