But when it’s time to buy strings it’s easy to be overwhelmed by the variety of brands, materials used in making them, and string thicknesses referred to as “gauge.” Back when I started playing the choices were much more limited: nylon or steel, steel or brass wound, basic gauges and brands. What I’m going to try to do is throw out some basics, not define what you should be using in absolutes. Oh wait – there is one absolute. You should never put steel strings on a guitar designed to use nylon. This is because nylon string guitars (classical style, with a “slot” head onto which the strings are attached) are constructed with much lighter interior bracing and thinner tops to better transmit the vibration of the much lower tension of nylon strings to the body of the instrument. If you make the mistake of putting steel on a classical guitar you are asking for big trouble in the form of cracks, warping, even a bridge coming off. However, there is one exception. More on that in a minute.
If you do have a nylon string guitar you still have some choices, mostly in terms of string tension. High tension strings are appropriate if you play with a heavy hand; moderate tension is best for all-around use in strumming or finger-style playing.
I’ll focus on steel string guitars because they are much more commonly used these days. There are basically two gauges of strings that are popular on steel string acoustic guitars: medium (.013, .017, .026, .035, .045, .056, highest to lowest in fractions of an inch in diameter, with the high E and B strings unwound and the remaining four strings wound with an alloy of brass or bronze) and light gauge (.012. .016, .025, .032, .042, .054). You may find some very slight variations in what are called medium and light gauge from one manufacturer to the next but these are generally accepted diameters. There are also “custom gauges” that include thinner high strings and thicker low ones, plus sets that are labeled extra light. In almost all cases, what you gain in ease of play with extra lights is more than negated by their weak, thin sound. But some people like them anyway, particularly players who primarily use electric guitars, which almost always are strung with very light strings.
Mediums have their place. If you are a very aggressive player or need to be heard in a band with other loud instruments such as a banjo, mediums make sense. In fact, virtually all bluegrass style guitarists use mediums. There is definitely more finger pain involved with mediums however, compared to lights. Some guitars respond better to mediums due to their heavier tension and anyone who strums most of the time may find that there is less string noise with them. The reason I gave up using mediums many years ago is more pragmatic. Even though all guitar makers claim their instruments can withstand the heavier tension of medium gauge strings I absolutely believe that over a period of time they can cause problems even with the finest of guitars, things like necks that go out of set (the angle and distance of the strings from the fingerboard) and bridge plates gradually becoming loose from the underside of the top of a guitar, resulting in a pronounced arching up – warping – of the top. I know some guitarists and luthiers would argue this but I stand by my opinion. I’ve seen mediums do serious damage to some very nice guitars.
So that leaves my preferred string gauge, light. Yes, I’m probably losing some volume by using them but the advantages of less stress on my guitars and my fingers (!) more than make up for that. So, my advice is stick with light gauge.
Now that exception for those playing guitars made for nylon strings, and this goes for very small bodied steel string guitars too like parlor or single-O size. “Silk and Steel” strings may be worth trying. They are a very light gauge softer feeling steel, unwound for the high E and B or with light steel cores on the other strings with nylon and light brass windings. These are very low tension strings compared to regular steel ones and if you really want or need that steel string sound but only have a classical guitar they might be just the thing. However, keep a very close eye on the bridge and the action of your classical – if you notice any changes, take them off immediately and go back to the nylons.
The alloys used to make steel strings are a long, separate discussion that I won’t get into now. Your basic choices are phosphor bronze and 80/20 bronze/brass alloy. Both types have their fans but I find the phosphor bronze much more pleasing, less harsh than the other. Also, some strings such as Elixers and Martin SP Lifespans have a micro plastic coating that is supposed to make the strings last longer before they go dead. My experience with Elixers is quite negative; to my ear they sound harsh and squeaky when you move your fingers. The Martins seem not to have those tendencies. Unfortunately, all coated strings cost at least twice as much as regular ones.
My bottom line advice is to try out many different brands of strings. You will surely find one that sounds great on your guitar (but may NOT sound so good on your friend’s!). As I said at the beginning, new guitar strings are a small investment to make to bring your guitar to its full potential.
Peace & good music,