When players go on stage, some of them have already been playing for a quite some time. It's especially important for wind and brass players.
Every french horn player has their own bespoke warm up routine. They can be as long as 30 minutes long. Over the years you get to recognise them.
It's a long and repetitive, tedious, but necessary process. Some do it hiding in corners, others while reading a paperback or Kindle.
They have to know exactly how their face muscles are going to work. Every day is different. There's no room for error. Split notes are a thing of the past.
As Maurice Handford, assistant to Barbirolli and trainer of hundreds of music students at the RAM, once said: "That style of playing went out when I stopped playing the horn".
The larger brass instruments need plenty of room and can often be heard in backstage corridors and stair-wells.
Trombonists are especially keen on warming up. After they come onto stage they might have to sit for half an hour before playing a note. You may spot them sometimes playing along with bits that composers didn't include them in, just to keep warm.
Denis Wick who has manufactured thousands of trombone mutes and mouthpieces, used to be our principal trombone. He once told me that he had a 30 minute routine. He did it every day whether he was working or not, just to keep his chops in shape.
Maurice Murphy our Star Wars hero once remarked that he loved airport lounges. Why's that Maurice? "It's one of the few places you can't hear a trombone warming up!".
Did you ever notice Maurice at the end of a concert that had been a big blow. He could be seen doing what looked like a horse impression. Maurice wasn't a big one for warming up, but he did like a good warm down.