Subjectively, higher string gauges will result in a “thicker”, “fatter” or “louder” tone, while lighter string gauges will result in a “thinner”, “brittle” or “weak” tone. While there is much truth in those statements, overall there are other, more important factors that affect tone than string gauge alone. Very discerning/experienced guitarists choose different string gauges for different amps and guitars as it is usually the interaction of all components in the set-up that results in their tone. If you want to improve your tone, simply increasing the gauge won’t necessarily do anything for you; you need to choose your string gauge with regard to the rest of your rig. Tone is a result of the interaction of each part of the chain (we’ll look at this more in a moment).
Since heavier strings have greater mass than lighter strings, they have greater inertia. Thinking back to high school physics, you will recall that inertia is the tendency for an object to resist changes in motion. Also, remember than inertia not only affects moving objects, but is also the tendency for stationary objects to resist changes in motion. This means that when you pluck a heavy-gauge string, the string will be slower to respond than with a light-gauge string, which results in a less ‘punchy’ attack to each note. Similarly, once the string is vibrating, a heavy-gauge string will take longer to die away than a light-gauge string. In a nutshell, higher gauge strings will result in a slower attack and increased sustain, whereas lighter strings have a stronger attack, but less sustain.
Anyone who has played with compressor pedals should note that this slower attack and longer sustain of heavy strings, is similar in effect to a compressor set with a long decay time. Thus, higher gauge strings have a more ‘compressed’ sound than lighter gauge strings. One reason I like heavy strings on slightly driven tones is that the softer attack means that the amp won’t distort unpredictably at the start of each note. Lighter gauge strings with a slightly driven amp tend to have a very gritty and overly distorted attack which doesn’t suit my tastes.
Another factor affecting your choice of string gauge has to do with the harmonic content of the string. Heavy strings need to be tighter than light strings for a given pitch, and it’s also the case that tighter strings produce stronger harmonics than lighter strings. Overall this means that heavier strings have a ‘brighter’, ‘clearer’, more ‘lively’ tone than lighter strings, which tend to produce more of the fundamental.
Heavier strings naturally sustain longer, but they also interact more with the magnets in the pickups, which tends to dampen the sustain. The gain in sustain from the heavier string tends to approximately balance out the loss of sustain from the extra magnetic interaction – so the net effect is a string which sustains for approximately the same amount of time!
Because energy is a closed system, the decrease in sustain due to magnetic interaction is effectively changed into an increase in the inducted voltage. The extra material of the heavier string causes more voltage to be inducted into the pickup coil, which results in a louder output.
Of course, if you lower your pickups, you’ll lessen any increase in output, and restore some of the extra sustain which the heavier strings bring.
So, in short, heavier strings tend to have stronger harmonics, a more compressed attack, and a potentially higher output and/or longer sustain.
There are many players out there who have followed the ‘heavy-gauge-means-better-tone’ idea to its extremes. If you absolutely must have the most compressed, loud, thick and harmonically rich tone possible then by all means, heavy gauges may just be the ticket. But often you can achieve sufficiently appealing tone factors without resorting to extremely heavy gauges.
Rather than achieving a compressed sound from heavier strings, you may like to consider simply using a compressor pedal. Whilst this doesn’t create exactly the same sound as heavy strings, the effect is still quite similar. Also, if you’re using under-wound pickups, you may like to consider a slightly hotter pickup, which can often create a more compressed tone.
If it’s the louder output of heavier strings which you find appealing, maybe you would like to try a higher output pickup, or simply raise the height of the pickup in relation to the strings. Also, you may consider using a booster pedal if you just want to push the amp a little more.
Before you settle on heavy gauge strings, experiment with other ways of achieving your tone. Like I said earlier, tone is a result of every part of the signal chain working together, and string gauge should be chosen to sensibly match the rest of your set up.
On acoustic guitars the effect is similar. Obviously, most acoustic guitars don’t have magnetic pickups so there is no magnetic damping. This means that heavier strings tend to sustain more, and are also louder. The general rule that heavier strings have stronger harmonics and a more compressed attack also applies.
This is a simple point but one worth making. If you want to use ‘dropped’ tunings where the strings are slacker than standard tuning you may want to consider using heavier strings. This ensures that the lower tunings can keep in tune, and that the strings maintain a good tone at the lower tunings. It is not uncommon for players who use ‘drop D’, to purchase hybrid sets of strings which are a standard medium light set (say a set of 0.010s), but have a heavier low E string, which makes drop D tunings maintain better tone and tuning stability. Also, if you plan to have your guitar in dropped tunings all of the time, you may like to consider purchasing a set of strings specifically for the intended tuning. Again, these have potentially better tone, and better tuning stability.
Of course if you want to use sharper tunings, you’ll want to make sure that you use a lighter set of strings. Also, if you ever want to experiment with extreme tunings, make sure that you visit your guitar tech first, to ensure that your guitar is properly set up for the new strings, and make sure the guitar is ready for the extra stress and tension that alternate tunings can cause.
Obviously the main disadvantage of using heavier strings is that they are more uncomfortable, and generally require more effort to play. If you play with lots of bending and vibrato, this can also result in too much muscle tension in the hand and wrist. If you choose to play with heavier strings, watch out for any tell-tale aches and pains which may indicate that your technique isn’t quite ready for heavier strings. If this is the case, a teacher can work with you on your technique, or you could switch back to a lighter-gauge set.
Also, even if you do have a good, relaxed technique, you may still find that constant practice on very heavy strings will tear several layers of skin from the tips of your fingers. Different people’s skin will callous differently, so you may not have any trouble with this. As a case in point though, Stevie Ray Vaughan who is well known for his heavy gauges, is reported to have used super-glue on the tips of his fingers to create artificial callouses for extra protection (although I’ve used this trick, I don’t recommend it since there could be long-term health effects as a result of regular application of super-glue to the skin).
Regarding tone, there is one significant drawback to using heavy strings, which is how it affects vibrato, and other subtle expressive techniques. Since heavier strings are harder to play, they are also harder to ‘finesse’. Using a string gauge that is not suited to a player’s finger strength and dexterity masks the idiosyncrasies of the individual player. Many people, myself included, feel that these small, subtle differences between players are important to the overall tone, and makes each person’s playing unique. So, heavier strings may increase volume and harmonic content, but might also make expressive playing more difficult.
For electric guitar I now use a 0.009-0.042 set with an unwound G string. This is pretty light, even though I have played (much) heavier gauges in the past. I personally no longer see a strong argument for using very heavy strings, although if I were to play a shorter scale instrument such as a Les Paul for example, I would almost certainly use a set of 0.010s at minimum – otherwise the strings tend to feel like rubber bands
On acoustic guitars though I definitely recommend heavier strings if possible, particularly for rhythm playing rather than finger-style. Acoustic guitars have the advantage that they are not usually used for lead playing, so the heavy strings tend not to be a problem. Heavy strings also allow you to play fairly hard, without the sound breaking up or going out of tune, whilst quiet playing still sounds ’solid’ and confident. Essentially, heavier strings will allow for a greater dynamic range on acoustic instruments. If you’re a finger picker, though, you may like to try a lighter set, such as 0.011s or 0.012s. On a well made instrument, you should still be able to achieve a ‘good’ tone without having to sacrifice any of the more ‘delicate’ maneuvers which finger-style can require.
PS it’s worth it to mention this quote from a user on the My Les Paul Forums I found:
it’s worth remembering that a lot of those 60’s and 70’s legendary players used 09’s if not 08’s!
Clapton used to string his Les Paul with 08’s when he recorded the seminal “Beano” album, the album which started the whole “Les Paul/Marshall” thing with a Tone by which all the other Tones are still measured!
Same thing with early Beck and Page during his Zeppelin years, and as far as righteous Tones they don’t come any better than that!
Let’s not forget John McLaughlin and Al Di Meola with the Mahavishnu Orchestra and Return to Forever respectively; and Tommy Bolin , Yngwie, Billy Gibbons, Brian May, the guys in Judas Priest…all 08-38’s users.
Additional note: Angus uses 009-042!
Since I found that out for good, I moved to 9s (from 10s) on ALL of my guitars, including ACOUSTICS!