This month I decided to discuss all of the many things which I have heard said about doubling on various instruments, as well as my own personal experience with it.
First, I want to let the evidence speak for itself. There are many musicians who have successfully demonstrated a high level of musicianship on more than one instrument. For one example, there is James Morrison (http://www.youtube.com/watch?v=-T-V7CA1Ksg). On the other hand, there are plenty of teachers who advise their students to play only one instrument.
Conventional wisdom suggests that more time spent practicing a second instrument steals time from practicing the first. After all, supposedly one of the lessons our civilization has learned from the industrial revolution was that it is most efficient for labor to specialize. Trying to play more than one instrument seems to run completely contrary to this wisdom, yet many people do it successfully. In fact, many doublers even claim that playing more than one instrument has made them better at each of their instruments.
My own experience has been precisely the latter. Playing both the trombone and the piano has given me two entirely different perspectives of music. I often draw on my experiences with both of them in my playing as well as teaching. Doubling has had such a profound impact on my musical development that I couldn’t imagine not playing both instruments. I also used to play double bass when I was in grade school, but I never developed much proficiency with it. In fact, my lack of progress with the bass has helped me to understand why I think many musicians get themselves in trouble trying to double.
No matter what anyone says, the key to playing any instrument at a high level is technique. It can also be somewhat difficult to manage, even on a single instrument. Every musical instrument requires a unique set of precisely timed and coordinated motions in order to successfully control it. It takes many repetitions to refine each motion until consistency can be achieved. Regular practice is necessary to constantly improve and maintain each motion.
That being said, practice should not be measured in minutes but rather in successful repetitions. A good measure for me has been to practice until I can make five successful repetitions of something new. I also try to keep both mental and written records of my practicing so I know when it has been too many days since I last worked on some skill.
I often tell my students that when I’m in shape I can get through everything I need to practice in a given day in about 90 minutes per instrument (3 hours total). When I’m not in shape it can take much longer. Therefore the key to efficiency with practicing is to stay in shape. I also practice both of my instruments in rapid succession. That is, I will spend 15 minutes or so playing trombone and then 15 playing piano, and then 15 more playing trombone, etc.
In other words, I don’t think of it as playing two different instruments. In my own mind, I play one instrument . . . the “trombonepiano.” Sometimes I blow into it, and sometimes I press down keys. Having talked to many successful doublers, I have heard similar views. One trumpet player friend of mine told me he advised his students to play their B-flat, C, E-flat and piccolo trumpet interchangeably until they didn’t really even notice which horn they happened to pick up.
There is also an advantage to this approach. When it comes to basic musicianship, everything applies equally to all instruments. If you have intonation trouble on one instrument, you will likely have similar problems on all of them. If you have impeccable time, that will likely carry over as well.
I would compare playing multiple instruments to learning multiple languages. Most people can be bilingual if they have a reason to be without it hurting their ability to speak either language. Learning any language is no easy task and requires constant practice of many precise small muscle motions (very similar to playing a musical instrument). If you lack the constant incentive to learn a second language you probably will not get very far with it. We also seem to learn all of this best when we are young. Trying to take up multiple languages at the same time in our mid-twenties or beyond will probably confuse us greatly.
It’s a somewhat surprising aspect of how the human brain works. In fact, many people who are multilingual can attest that knowing several languages has given them a lot more insight into each individual language. It’s really all about neural networks. It all works as long as you keep practicing the basics of technique on every instrument and constantly stay motived to maintain it. Starting when you are young doesn’t hurt either.
That being said, there are definitely limits to this. Eventually you run out of time to learn all the music you need to learn. There is also the element of confidence. It is important to log time in front of audiences which make us nervous regularly on each instrument. For these reasons, I generally advise students against playing too many instruments. However, learning a second instrument (particularly one quite different from your first) can yield invaluable insight into music-making. I highly recommend it!