Violin strings aren’t really made of cat gut. “Gut” strings are made of sheep intestine. They are preferred by many classical violin players, but don’t stay in tune well, so many musicians choose to use steel or synthetic core strings instead. Steel strings are very bright sounding and very stable (they don’t get out of tune easily). And they are loud. Synthetic strings are a bit softer in sound, but still brighter than gut, and also stay in tune fairly well. Each instrument needs the strings that will make it sound best, and there’s no magic formula for figuring this out. In general, if the instrument is a soft, mellow one, I will put brighter strings on it – perhaps Prim or D’Addario Helicore. If the instrument tends to be brassy, I usually go for Thomastic Dominants. Unfortunately, fiddle strings are pretty expensive. Sometimes you can get someone’s used strings to try before you buy. Inexpensive strings … well they sound like what you paid for them. So I set up each instrument with the strings I think will work best for it.
The violin is tuned G D A E. The lowest string (also the thickest one, the one to the left as you hold the scroll away from yourself) is tuned to the G below middle C on the piano. The next highest string is the D right above middle C. The next string is the A above middle C. And the little, skinny string on the right is the E a full octave and two notes above middle C. If you don’t have a piano, you can use an electronic tuner or visit Tuning Help to produce the needed tones for tuning. You can also use an electronic tuner to check yourself after you’ve tuned with the piano or the tones on this web site. If you’re not a musician, it may be difficult to match the pitches at first. Don’t become discouraged. It’s a skill that will develop over time.