Once you have a violin adjusted to sound its best in terms of volume, evenness across the strings, responsiveness and good dynamic, then it comes down to other qualities that players seek: bright, dark, gritty, smooth, warm, focused, muddy, clear, etc. The string industry continues to develop a plethora of strings to address the needs of varying violins and varying listeners and players. That's great, there's probably a string that allows a violin to sound "right" for every player. Certainly, there's at least 1 brand of string that sounds best on every violin. But, with the average price of a set of strings hovering in the $100 range and with the average playing life of about 150 hours, most people are reluctant to do much experimenting. As a purveyor of strings, I'm reluctant to carry a lot of inventory as the markup on strings is slim and it doesn't take long to have several hundred dollars worth of open stock kicking around in the cupboard.
I've adjusted to the situation by primarily stocking 3 brands of strings. Dominants, because they are the standard (although I would argue that Tonica strings are as good or better since they were reformulated a few years ago). Most players grew up on Dominants and rely on them as the standard, so I carry them instead of Tonica. Dominants are resonably priced, reasonably stable, and last a reasonable length of time.
If I think a violin tone needs to be warmed up, I go with the more costly Obligatos. They produce a nice complex sound, are very stable and also last a long time. Lately, I've been thinking about Infeld Red stings as an alternative to Obligato strings. They cost less and I've had good luck with them.
If I need more strength than Dominants, I have Evah Pirazzi's. The sound is complex and the strings are stable, although the tension is relatively high.
I haven't found anyone that loves the Dominant E string. Right now, I'm working with Goldbrokat E (inexpensive), Eudoxa E (wound and pricey) and recently Infeld Red E (very pricey and gold). Depending on the fine tuner on the tail piece, I need to carry 2 flavours, ball end and loop end.
Let's not forget, that since most strings come in 3 gauges: light, medium and heavy, I need to carry at least some of the other gauges. For now, I carry the Eudoxa E, Dominants and Obligatos in the heavy gauge.
My string box contains a lot of orphans and misfits. For example: the low tension and warm Violino, the smoky Larsen Tzigane, the revolutionary Warchal Amber, the ultra expensive Evah Pirazzi Gold, the gut core Passione, the Fiddler's economical Prim and the bargain basement Pro Arte. The orphan E strings in my collection include the Pirastro Gold E (pretty good) the Obligato gold E (also pretty good) and a few others that have become nameless. Most of these will probably lie dormant for years until they find a suitable instrument.
I always start with Dominants on a new instrument (because over their 40+ year history, they have become the standard), and while I can then guess which brand of string will have the best effect on a violin, I'm often wrong. I'm starting to think matching strings to fiddles is unpredictable. Which means, I keep open stock on hand so that I can try the different brands on the same fiddle. If I'm lucky, I have someone else go through the exercise with me, so that we can compare what we hear. Also, the strings often (but not always) sound different under the ear, compared to listening to someone else play.
Yesterday, I had a couple of friends provide feedback on the tone of the fiddle pictured above. I did extensive soundpost and bridge work on it, and I had gone from Dominants to Obligatos, so I needed some unbiased perspective on the work I did. Based on the first round of play, I moved the soundpost to bring more focus to the tone. Based on the second round, I switched back to Dominants. The third round of play indicated that the Dominants improved the tone, but it was a bit gritty. So, we switched to Pirazzi strings. The next round of play was the finale. This violin is now sounding it's best, which, in my opinion, is the first time it has done so, since I had Dominants on it as a new violin 18 months ago. Interesting how Dominants worked at one time, but changes in the violin over time required a string change to Pirazzi's later on.
Simply going into a store and purchasing a different brand of string is not going to guarantee tonal success. On my creations, I start by ensuring the bridge and soundpost are set up to give optimal performance. Then, I keep open sets of strings on hand so that I can encourage people to try different strings on violins to see which ones work best before they commit to a violin purchase. I've also found it is very beneficial to test strings with the help of others. Interpretation of tone is somewhat subjective but confirmation on what you are hearing feels good, and disagreement brings about deeper discussion and greater understanding.
When people are searching for a new violin, they often quickly dismiss excellent instruments because of the first tonal impression. This is unfortunate, because a simple change of strings could result in the discovery of a life long soul mate.
As an update to the example I mentioned earlier, I've been playing on the Pirazzi strings for a week and am thinking the tone is not quite for me, although I know lots of people would love it. I think I favor the Obligatos, but tomorrow, I will gather my cohorts, and try a fresh set of Infeld Reds on it. Apparently I still have the fever.