How to Improve Your Trigger Register
I was recently asked by someone how to play a great low C on the tenor trombone. Concern about the general trigger register from low Eb to low C is something that I hear quite often. It seems this area of concern comes up more often when a 2nd trombone audition is looming and those low excerpts from Mahler 5 are on everyone's mind. The first thing I ask someone when they complain about their low register is, "How often do you play in your low trigger register?". Inevitably, the answer is usually very little at all. I think that's the first problem. If you want to improve your low trigger register, you need to play more low trigger notes!
For a long time, I started every day with very slow descending scales that started on a middle Bb and went down to pedal Bb at a comfortable dynamic. Then I'd do the same thing on A major, Ab, G, etc. until I couldn't get my lowest notes to speak. This process accomplished a lot of things right away. I had a teacher who once told me that the purpose of a warmup is to establish the way you want to play for the remainder of the day. If you start off your day making beautiful sounds, there's a good chance that you will continue to do so as the day goes on. Since a middle Bb is a pretty easy note to sound great on, I would start there and work to maintain that beauty as I descended. The series of scales got me accustomed to playing a beautiful sound and moving a lot of air. As it directly relates to the point of playing more often in the low trigger register, these scales had me playing a ton of notes in that register within the first ten minutes of my day. As a result of that, I'm pretty comfortable in that range.
There are a few technical things to think about in regards to the low trigger register. Most people have a shift where they drop their jaw as they approach the extreme lower register. I do this as well. One problem I notice in a lot of players is a loss of structure in the embouchure after this shift. Make sure that you still maintain a real sense of structure in the corners of your embouchure in this low register. Too many people are quick to just let everything go and completely let all of their facial tissue flap in the wind. As a result, the tone becomes unfocused and out of tune. The further and further the slide goes out, the more difficult it becomes to focus the notes. The combination of an unfocused embouchure and an extensive amount of tubing (think Low C in trigger 7) makes for a very unfocused note. The person who asked this question also mentioned a concern about playing loud in this register. This goes along with my point. If you have difficulty centering the note, how can you possibly manipulate the dynamic? As a quick reminder of how things should feel in your corners, play the C an octave or two higher and take a mental picture of the support in your corners. Try to recreate this level of support in the lower octaves despite the fact that your aperture will be more wide open.
As for the air stream, I would think about blowing a relatively slower, wider air stream. I often times use the analogy of General Zod blowing cars down the street in Superman, but younger kids can't relate to that anymore. It never seems like Zod is working very hard, but there's obviously a lot of air moving there! I tell people to relax. Playing loud in the low register is one of the most relaxing, free blowing, tension free things to do. When I'm in this register I like taking a LA-Z-BOY breath. By that, I mean I think of sitting far back in a nice relaxed chair on Sunday afternoon watching some football and being 100% carefree. Take a huge breath, set your corners just enough to that there is structure and just let the air go! Don't make it any more complicated than that!
I hope this tips helps. For those interested a great fight scene from Superman 2, see here.