I've been playing the viola for quite a few years. Recently I got a 16.5" viola and noticed that it was harder not to get a scratchy tone, especially on the A string. I noticed that tilting the bow hair away from me improves my tone quite a bit for the higher strings. However, my current orchestra teacher repeatedly tells me to tilt the bow hair towards me, which actually worsens the tone. I've never had anyone else tell me that. Is it correct to tilt the bow hair a certain direction, or is it up to preference?
Honestly, I don't think it makes much of a difference by itself. On cello, the standard way to mellow down the sound is to angle the bow towards yourself – but that has the opposite effect as on violin / viola, namely that only the hairs farthest away from the bridge touch the string.
The important points seem to be
- Few hairs on the string, no matter which ones.
- Good control of pressure & speed. This is surely always the most important aspect. For this, it helps to have a comfortable hand position. Most players probably find it easier to tilt the bow towards- rather than away from yourself.
- Using hairs which are in good condition. Both sides of the bow are subject to different wear, and also perhaps given slightly different amounts of rosin. If you think you like the tone more when tilting the bow away from you, perhaps you should try whether this is also true when you're using a different bow!
The normal way of tilting a bow on violin and viola is to tilt it so that the hairs farthest away from the bridge touch the string just like on a cello.
But since the bridge on a violin and viola is between you and the bow while on a cello the bridge is behind the bow you are tilting the bow the opposite way on a violin and viola compared with cello in order to get the same result: The hairs farthest away from the bridge touch the string.
There can always be exceptions to normal techniques, sometimes you find your own solutions. But it is usually a good idea to learn basic techniques first.