Thoughts on Flat Hair
I'm amazed at how often the flat hair issue comes up among bass players. Apparently, some teachers are pushing the use of flat hair, or maybe it's that students are getting carried away with a certain suggestion. There are students and young professionals who mindlessly use flat hair all the time. When someone plays for me who consistently uses flat hair, I feel a bit uncomfortable suggesting they do otherwise, because I think their teacher must have worked pretty hard to get them to play that way. I hear nothing but an uninformed, spastic approach to sound production. I'm quite sure one cannot control sound effectively with an all-flat-hair approach.
I guess the argument for flat hair is: the more hair touching the string, the louder the sound produced. It's an over- simplification and mostly just wrong! The easiest response to that I can think of is a comparison to painting. Suppose you were given a large brush - the type used to paint houses- and asked to paint a detailed portrait of someone on canvas or paper. Could you do it? Well, you might be able to pull it off, but I couldn't, and certainly not if I were asked to use only flat hair with the brush, so that all of the hairs were touching the surface equally all of the time. (Now there's an exercise for an art class!) For the basic background color, I could spread a lot of paint over the whole surface pretty quickly, but if I were to draw an outline of a figure and add further details - no way! With the big brush, I would want to turn it on its side to get thinner lines, and maybe just use an end for some curves, and then maybe just a clump of ten or fifteen hairs for dots for the eyes. Ideally, you'd really want an assortment of different sized brushes to do the job well.
In the same way, a string player can't possibly be an effective artist by limiting one's self to flat hair. The amount of hair used must constantly adjust to the need of the moment. For instance, in very light playing, like in the opening of the third movement of Beethoven's Fifth Symphony, you tilt the bow up a bit and use fewer hairs (and also place the bow more toward the fingerboard). Fewer hairs usually are more effective in piano playing than the whole bundle.
Here's another example: You're playing the Koussevitzky Concerto and you want to play with big, romantic "chops" like Rostropovich or Yo - Yo. Well, with all that passage work in thumb position, the intense bow pressure, and bowing closer to the bridge, you don't want to mindlessly use flat hair. The G string in those high positions gets shortened by 50%-90%, so one might find some things work better with a bit less hair, too. I find perhaps a bigger issue in that high range is hair tightness. If it's not tight enough, you have too much hair contact and it wraps around the circumference of the string more, further choking the sound. The lower positions are more forgiving with loose hair.
I think there should almost always be a sense of a leading edge of the hair, which requires a degree of bow tilt. As explained above, it's important to limit hair contact as necessary. However, when I play forte, the hair may indeed be nearly flat, with all of my bow hairs contacting the string. The important thing is that I still maintain a sense of leveraging into the string which is accomplished in part with a slight upward tilt. I think it produces the optimum sound. In a sense, I impose order on the hairs, giving them a hierarchy of responsibility. The hairs closest to the fingerboard will have the most pressure and do the most pulling, while the others have progressively lighter contact and less pull. It creates a focal point in sound production rather than having all of the hairs competing. We're talking small degrees here, things that are quite subtle but that can have a significant effect.
With a stretch of the imagination, another correlation could be skiing. Your skis are flat if you go straight down a hill, but to make turns and gain control, you've got to tilt your skis a bit on edge (as you shift your weight), digging the slope-side edge into the snow. In the same way, I like the feel of digging in and getting control with the bow.
In further support of this idea of bow tilt, I will sight one source which I read the other day and to which I could completely relate:
In the April 2008 issue of The Strad, violist James Boyd posed questions to himself to shed light on the issue of gut strings. I don't play on gut strings, but, at one point he makes the following comment: "Possibly the most important aspect when playing with gut is the need to be aware that the tilt of the bow makes a big difference to the tone colour. If our bow hair is too flat, the sound will become choked." His point is that gut strings can't handle flat hair as well as steel strings. But he goes on to say, "If we play with completely flat hair, we have many leading hairs vying for supremacy and they fight each other, destroying the clarity and core of the sound." Gut or steel, it's the same phenomenon with the bow hairs.
Granted, a musician has to do whatever is required to get a desired effect. If the sound you want is best produced by playing flat hair, by all means do it! But be careful to not get locked into a technique or approach which can profoundly limit your ability to draw nuances and a beautiful sound over the whole range of the instrument.
