I had wanted to talk about this topic for some time now as I realize my ability (and willingness) to sing while playing the cello puts me in the minority of instrumentalists of many if not most genres–and especially with the minority of instrumentalists who play bowed stringed instruments.
Singing isn’t the issue here, we’ve probably all sung privately (in the shower?) if not publicly (for good or ill). But a particular thread at the Cello Chat forum (as well as a number of the comments really hit home how, um, “unorthodox” it is for cellists to sing while playing.
I know that some of this goes back to some of the things I talked about regarding the role of the performer (for the numerous facebook comments on that post, go here) and that generally people have a relatively narrowly defined and arbitrary notion of what it means for them to be a musician.
As far the difficulty level–well, the most difficult thing about doing it is just getting over the inhibition that’s keeping you from doing it. There’s really nothing to it and once you get the hang of singing while playing it, like everything, starts to come more naturally.
Sure, there are some things that are more difficult to do–playing a particularly difficult passage or singing a particularly demanding vocal line-but what I’ve found the most tricky is playing sustained melody on the cello, while singing a sustained melody or counter-melody (or vice versa). It’s an issue of keeping track of completely different lines that really divides the attention thus preventing you from focusing on one or the other more fully. In other words, what works well, is being able to put one or the other (either playing the cello or singing) in “automatic mode” so that you can focus your attention on the [usually] mre demanding line.
I’m sure singer-songwriter types already know some of this and have tons of experience with the techniques that bowed string players have to struggle a bit with, but it’s not something cellists can take for granted. And personally, I think singing while playing should become a part of the pedagogical process for any instrumentalist for which it is even possible (wind players excluded, for obvious reasons).