Why do cellists have different strings for A&D and G&C?
I'm a violinist myself, but have wondered especially at all the all-county and all-state orchestras, why cellos often have two different brands of strings on their instruments.
Us violinists usually have ADG one set and a different E string, but who do cellists split between the two?
What about Basses and violas?
The vast majority of violists I've encountered, at or above upper-intermediate level, use one brand for CGD and a second for A. In California, I would estimate 50% use Larsen A, 30% use Jargar A, and 20% use all other brands combined. I have yet to meet any violist in person who uses Larsen or Jargar for any string other than A.
Compared with violins, cellos vary in tone qualities quite a bit, not only from other cellos but also across their range, and choosing strings carefully can balance that out and smooth over the changes one might need in bowing to approach the different strings. Without intervention, commonly, the C string can lack clarity, the G sound like someone pounding on an empty oil drum, the D can sound dull, and the A sound harsh. Some of this can be dealt with in set up, the rest with string choice. Violins are much more homogeneous on their own, without a lot of fussing around.
Years ago the printed SHAR catalog had an interesting feature. Each issue featured the strings used by several of their employees. Most of these were using mixed sets. I believe they may also have described the instrument each of them played. Mixed sets were common. Personally I used mixed sets on my violins for at least 30 years until about 5 years ago when I moved from Peter Infeld, to Thomastik Vision Solo, to Evah Pirazzi Gold - but I've kept the same Peter Infeld platinum E on throughout that evolution - and have no sonic reason to ever deviate from my current setups.
On my cello, Spirocore were more responsive and full on the C and G, but not as nice on the treble. I liked the sound, feel, and response of Aricore on the treble and the C and G were too flacid, cloudy, and less quick. On my fifths bass, I have found a similar setup with Obligato on the treble for identical reasons.
The new Jargar Special A (forte) was recommended by several pros on Cello Chat a few months ago and I am very happy that I installed them on 2 cellos.
Having two or more different string brands on your violin indicates that you have sufficient disposable wealth to choose them empirically. Of course the price of a set of strings is probably less than the cost of two lessons, but nobody sees you taking lessons.