Take guitar strings. When I started playing back in the 1960s there were four or five brands that were readily available and the choice of materials was pretty much limited to nylon, brass and steel. I do remember a jazz guitarist I knew who insisted on going to a store that had a big box of strings on the counter, divided up in sections by string gauge and whether they were flat wound or round wound. He would buy individual strings to make his sets because the basic sets that were available just didn't suit his needs. I used to buy the cool black nylon LaBella "Folk" strings with ball ends for my Harmony classical guitar. Gauge? Who the heck knew or cared?
I was recently perusing the online catalog of a mega retailer and I counted 26 different brands of acoustic guitar strings, in which there were 519 variations! And you know what? My favorite brand wasn't even there! No wonder guitarists get confused and may secretly wonder if there is all that much difference.
I'm not going to attempt to delve into the specifics of those 519 variations. Heck, I couldn't if I wanted to because it seems a new string company pops up every week. And just about the time you find "the one," that perfect string, you can't help but wonder about the brand you used a couple years ago and if it was really as good as you thought back then. So you buy some, and the process begins again. Ugh. This is can be expensive but also time consuming and it does not take into account things like varying humidity at different times of the year that will surely affect the sound and longevity of any string.
What I will do is try to boil the whole thing down to the basics. I'm going to talk about strings for steel string acoustics, which are my passion and where I have the most experience. Let's start with materials.
The most popular string materials for the wrappings of strings for acoustic steel guitars are 80/20 Bronze and Phosphor Bronze. Not that long ago brass was popular but for some reason that has faded away, or perhaps the 80/20 is what used to be called brass, I don't really know. You notice I emphasized that the wrappings are made of these materials. That is because almost without exception the cores of the wrapped strings and the unwrapped high E and B strings are single strand steel. There is some variation in the shape of the steel (round core or hexagon core being the most common) but except for how the steel is tempered to be stiff or more flexible, it is still just steel.
You'll find debate on this, but many guitarists feel that 80/20 is somewhat brighter sounding than phos. bronze. I agree with that. In fact, some brands of 80/20 are so bright that they begin to sound almost abrasive, at least to my ears. So I usually stick to phos. bronze. Some strings are coated with a micro plastic coating that makes them stay new sounding, longer. I tried those and did not like them because I found them to be to "squeeky" when my fingers moved. But many players love them even though they cost almost twice as much as regular strings.
Next comes gauge, or the overall thickness of the strings in aggregate. Manufacturers label their string sets as being light, medium or heavy gauge. There are other variations that I'll get into in a minute but these are the most common. Although you can find some discrepancies from one manufacturer to the next regarding the string diameters in the specific categories, here is the general consensus of string diameters per classification, from highest to lowest pitch:
Light gauge: .12 .16 .24 .32 .42 .53
Medium gauge: .13 .17 .26 .35 .45 .56
You notice I do not even get into heavy gauge. This is because all guitar manufacturers caution against using anything heavier than mediums because of the stress they put on the instrument.
And that stress is what it's all about. This is a conundrum that guitarists have faced for generations, ever since Martin and Gibson first produced guitars that were braced to accept all-metal strings back in the early part of the 20th Century. Medium gauge strings sound better than lights on almost all steel string guitars, but.... they HURT! And even though almost all guitars are supposedly braced to accept mediums, they definitely shorten the time before a guitar will need a neck reset (ouch!) and make guitars more prone to lifting bridges, cracks and other unpleasantness.
Lights are easier to press down but they don't exert as much pressure on the bridge, which means the top of the guitar will not vibrate to its maximum capability, which equates to less than optimum volume and resonance. In the extreme, some guitarists - especially those coming from an electric guitar background - will use Extra Light Gauge strings to make the acoustic easier to play. In my opinion, extra lights are all but useless - not only do they rob a good guitar of its best sound but they tend to rattle and buzz, especially when strummed. Do your guitar a favor. Skip the XLs.
String manufacturers have been listening to these issues however and some of them have begun marketing "custom" sets of strings. For example, Martin Custom Lights are a halfway point between XLs and lights and they sound pretty decent. My opinion is that if you can play these you can probably play a regular light, so why rob the guitar to volume and tone for just a tiny bit of ease? But that's your call.
Of more interest to me are the "medium/lights" that a few companies like John Pearse and Newtone (my absolute favorite brand) now make. These feature what are essentially light gauge treble strings and medium gauge bass strings, thereby getting some of the ease of lights, plus the punch of mediums, with less finger fatigue.
This is all pretty subjective stuff however. A lot has to do with the style of your playing and type of music you play. Someone who's in a pitched battle with his friend the banjo player in a bluegrass band will certainly stick to mediums, while the person playing some of the modern finger style music that requires a lot of hammer-ons, slurs and slides will probably be best served by lights. I fall somewhere in the middle (although thankfully I do not have a banjo player to contend with!) and I absolutely love the Newtone Master Class NMC-CU phosphor bronze strings that measure:
.12 .16 .24 .34 .44 .54
Newtones are made with a round core and are hand-wrapped, which results in a nice soft feeling string with amazing longevity.
There are some other variations that you should be aware of such as all-steel strings designed for acoustic electric guitars and silk-and-steel, which are a very light gauge, low tension string with a thin silk wrapping on the lower strings between the steel wrap and the steel core. These are great for very small bodied steel strings and can even be used on some older guitars that were designed for nylon or "gut" strings. Be careful using them and take them off at the first sign of the bridge warping or the top arching. If this doesn't happen you can end up with a very sweet sounding guitar. I once knew a woman who had a Martin "New Yorker" that was strung with silk-and-steel and it was a joy to hear.
So there you are. I really can't tell you which string is best for your style or needs but thankfully, compared to strings for other instruments like violin and cello, guitar strings are inexpensive enough to experiment with different gauges and brands. Just be aware that those "perfect" strings may be just one in a long line of perfect strings!
As always, I welcome comment and input on this and any guitar-related subject.
Peace & good tunes!