Acoustic Guitar Strings Explained

Acoustic guitar strings come in so many varieties, and from so many makers, that choosing the proper set can be an overwhelming decision.  Just what do the terms ‘phosphor bronze’ and ’80/20 bronze’ mean?  Coated or not?  Does it affect the sound?  Keep reading and I’ll explain how to choose acoustic guitar strings.

There are four main aspects to understanding steel strings for acoustic guitars:  Material, core and winding, coating, and gauge.  (Nylon strings versus steel strings is a whole other discussion, one which I hope to address at some later time.)


For acoustic guitars, the two most commonly used materials are Phosphor Bronze and 80/20 Bronze.  A few players use Nickel-plated Steel, but these are generally used on electric guitars.

Phosphor Bronze

Not actually bronze, but an alloy of 92% copper and 8% zinc.  These strings have a rich, warm tone.  They generally last longer than other types of strings.

80/20 Bronze

Based on the description of phosphor bronze, you’d expect these strings to be 80% copper and 20% zinc.  And you’d be right.  These strings have a brighter tone than phosphor bronze, but tend to lose their brightness faster.

Nickel-plated Steel

These strings are wound with nickel-plated steel, and are much more commonly used on electric guitars.  I personally don’t have any experience with these strings on an acoustic guitar.

Core and Winding

There are two main parts to a string: the core and the winding.  The core is the central part, over which a bronze winding (either phosphor bronze or 80/20 bronze) is then applied.  This is what gives strings their gold color.


Cores are typically made of steel, although a few types of strings incorporate silk into the core.  Most cores are round, although a few are hexagonal, which helps prevent the winding from slipping around the core.


The winding is one of the biggest factors in sound, providing mid-range and bass tones that are deeper and more sustained.  Windings come in two main types:  round and flattened.

Round.  The most common type of winding, and also the cheapest.  It is literally a round wire wound around the core.  Occasionally, the winding will slip off the round core and cause problems.  When this happens, the string will need to be replaced.

Flattened.  Less common than round, and also more expensive.  These windings are either pre-formed flattened before being wound around the core, or round windings are used and then ground down afterwards to flatten them.  One advantage of flattened windings over round ones is less finger “squeak” when playing.  Also, there is less space between windings for oil and dirt from fingers to collect.


When fingers come in contact with a string, when either picking or fretting, some dirt and oil from the fingers will be left on the surface of the string.  Over time, this gunk will collect and start to affect the sound.  Dirty strings are duller sounding than clean ones.  So, how can you keep your strings clean for longer and prolong their life?  One solution is the use of a coating, which is a thin, teflon-like plastic applied to the surface.  The coating acts as a barrier, making it more difficult for the gunk to adhere.

One other advantage with coatings is they reduce finger “squeak” when playing.  This is that sound produced when you slide your fingers along the strings.  As a player, you know that sound.  A few pros have learned how to use that sound to great effect, but if you’re like me, you’re not good enough to have mastered that trick.


Guitar strings are described by the gauge of wire used, corresponding to the diameter of the strings.  This contrasts with instruments like violin and cello, which are described by the tension they support.  Acoustic guitar strings are thicker than electric guitar strings because they are often played without amplification and so the thicker things allow greater projection, meaning they can be heard at greater distances.

Acoustic guitar strings come in sets ranging from “extra light” to “heavy”, with diameters ranging from 0.010 – 0.047 inches for extra light and 0.014 – 0.059 inches for heavy.  Generally, lighter gauge strings are easier to play, but are also easier to break.  Heavier strings often have a fuller sound and harder to break.

Which should you choose?  Well, it depends on your instrument, style of play, and preferred tone.  I recommend heavier strings on larger-bodied guitars to take advantage of that larger body, and lighter ones on smaller instruments.  Also, vintage guitars may not have the strength to handle heavier strings and the greater tension they put on the neck, so go with a lighter set on an older guitar.  For fingerpicking, lighter gauges are easier on the fingers, but heavy strummers should go with heavier strings because they will last longer under the greater pressure.  As for tone, lighter strings sound sweeter while the heavier strings will give greater emphasis to the deeper tones produced by your guitar.


With all that said, the most important aspect of strings is how they sound.  I highly recommend trying out different strings to find the one that sounds best with your guitar.  Remember that each guitar is different.  Two guitars, same maker and same model, will sound different because the wood used will be different.  The difference may be subtle, but careful listening will reveal it.  Every string maker likes to advertise that so-and-so star player prefers their strings.  And that’s all good, but take those recommendations with a grain of salt.  You might not get the same sound on your own guitar, so experiment and find the one that sounds the best to your ears.

That’s it for now.  I hope some of this information was helpful.  If you have a comment please leave it for me.  I love comments.

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Rock On!

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