Violin/Viola's High A String
Hello again Mr. Fisher. It's a pleasure contacting you again. I have a question about the relationship between the size of a viola and the thinning of the sound of the A string.
If the size of the viola is larger, does the sound from the A string get thinner?
Thank you again Mr. Fisher!
Thanks for your question. Unlike the violin, there has never been a real consensus, that I'm aware of, around the ideal theoretical size of the viola, even letting the practical issue of arm and finger length to one side. Different makers and theorists have, from time time time, stated that the ideal size should be anywhere from 16.5" to 18.5". But, of course, this discussion is all rather academic, since the length of the players arm and fingers MUST be considered.
The bottom line is that a larger instrument will support the lower frequencies better than a smaller instrument. It will sound fuller on the C and G strings. Smaller instruments tend to be brighter, not so much because they amplify the higher frequencies better, but because they don't produce as much of the lower frequency information, thereby resulting in an overall tone that is skewed toward the higher frequencies. So, I'd say: No, I don't believe that the tonality of the A would suffer in a larger instrument. If anything, I'd suggest that the A would be better supported and fuller in the larger instrument, though the improvement in tone of the A would not be as significant as the improvement in the tone of the C and G strings.
Keep in mind that every instrument is different. It's entirely possible that you could find a wonderful smaller instrument that produces a rich, deep tone. And, there are certainly many larger violas that produce poor thin tones across all the strings. But, all things being equal, the larger will give the better tone, even on the A string.
Also keep in mind that the entire frequency spectrum is involved and effected by the size of the instrument - not just the fundamental frequencies. So, it's not just a question of how the C, G, D, or A pitches are supported, or even the fingered notes throughout the instrument's range. It's also a question of how the instrument amplifies sound in different frequencies, right up to the limit of the human ear. Certain ranges of frequencies sound more nasal and unpleasant to the ear. An instrument that does not produce high frequency overtones well will sound focused rather than rich. The resonance frequencies of the individual pieces of the instrument also play a role in the complexity of the sound. And, all four strings vibrate while the instrument is played, not just the one strings that is currently being bowed. So . . . sorry getting off the question here. But suffice to say that in practice, it's much more complicated than in theory, and you really need to try a bunch of different instruments to find the one that sounds good to you. You might, for example, really like a bright sound to your tone, in which case a smaller viola could be a good fit. Or, you may find an instrument that doesn't conform to theory. As with so many things, it's a matter of balancing many factors to find the best overall fit for you.
But, again . . . No, in my experience, the A string generally does not sound thinner in smaller violas.