String tension

TheMadMick

Had a B string buzzing problem with my Auden parlour and took it to Mike Smith, the local luthier. When it got there the buzz had gone. However, it kept coming back and so I took Mike's advice and strung it with the next heavier strings (12 - 54). Hooray, the buzz has all but gone but what was more surprising was the tonal balance had improved no end. Before it was bright and "zingy" but now the balance is wonderful and more like I expected. I knew there would be a change but nothing this profound has happened before on my other guitars.

sev112

were you on 11s at 24.5” approx scale length ? That’s moved from circa 19lb force to circa 24lb
On 12s
ive got a GS Mini with 23.5” scale length and Taylor put 13s on those,  

ive got 12s on my main 25.5” acoustic, but they are a little tight for me, and I’ve been playing it tuned down to D and I love how much the guitar opens up and vibrates more, that’s at circa 19lb, but it is a little too loose I find. So I have some 11.5s arriving today which I’m hoping will find me a happy medium of playability / lower tension but still some of that lovely increased vibrations

TheMadMick

sev112 said:

were you on 11s at 24.5” approx scale length ? That’s moved from circa 19lb force to circa 24lb
On 12s
ive got a GS Mini with 23.5” scale length and Taylor put 13s on those, 

Just measured the scale length and it's more like 24.75. Not a world of difference. Unfortunately, I gave away the set of 13's I had but maybe it's worth getting a set to try?

Mellish

All acoustic guitars are different, even two J45s, say. My HD28 came with 13-56 PB, but I found they choke it and it really sings with 12-54 in 80/20. And strings, even a bunch of different brands in 12s, will not all have the same tension. You can normally find that on the back of each box/packet  

ICBM

In my opinion/experience, it's less to do with the extra tension in itself - it's commonly held to be a fact that higher tension gives more volume and tone from an acoustic guitar, but I don't think it's true (or only very marginally) - the tension is pulling forward on the bridge and top, not upwards and downwards which is what moves the top... and is mostly from the energy of the string vibration. (In fact, over-stringing a guitar can actually stiffen the top too much and constrict the tone.)

What also happens is that the extra string tension pulls the neck forward and the bridge and top up slightly - the increased relief and action then allows the strings to vibrate cleanly, whereas they may have been just rattling imperceptibly on the frets before. Fret rattle affects the tone and volume before it's bad enough to be actually audible as rattle - if it's just on the edge of being present, it just clips off the initial picking transient of the string - this isn't obvious as rattle because it's masked by the picking noise, but it robs a lot of energy from the string which greatly reduces volume and tone.

The 'sweet spot' for a guitar set-up is at the point where it's just high enough for this to not occur and the strings to vibrate cleanly - any higher, and you don't get any further improvement in tone but the guitar becomes harder to play.

So my guess is that bright 'zingy' tone was subtle fret rattle, and by going up a tiny bit in string tension you've pulled it into the 'sweet spot', where the tone is much fuller and more balanced.

TheBigDipper

ICBM said:

<snip>
The 'sweet spot' for a guitar set-up is at the point where it's just high enough for this to not occur and the strings to vibrate cleanly - any higher, and you don't get any further improvement in tone but the guitar becomes harder to play.

So my guess is that bright 'zingy' tone was subtle fret rattle, and by going up a tiny bit in string tension you've pulled it into the 'sweet spot', where the tone is much fuller and more balanced.

It might be interesting trying to play a little quieter to see if the reduced string movement makes the guitar actually sound louder. Many guitars reward a light touch rather than being played hard. And equally, get flabby or sound poor if you do whereas others just love being belted. 

DavidR

I think string tension can make quite a difference to an instrument actually.

One test of this (on an acoustic which is mainly all I know about really!) is tuning to open E (from 6th string - EBEG#BE). You can either do this by tuning some strings upwards without a capo or by using a capo on the second fret and tuning some strings 'down'. You'll end up with the same notes either way but with greater or less tension on the bridge (overall) depending on what you've done.

OK you're using a capo so some other things like action, string length, resonant frequency, harmonics will have changed and some will say this negates the exercise. Still interesting to do though.

Classical luthiers say it doesn't matter what you do to an instrument, it will change the tone. Even changing the tuners!

stickyfiddle

There are 3 factors at play:

• string tension 
• Relief (as described by ICBM)
• energy in the vibrating string, which is transfering to the top 

All of those increase with higher gauges, and 2 & 3 will make a guitar sound bigger and louder, in general.

But there is also the overall resonant characteristics of the guitar, which may change slightly with string tension. It's very hard to come up with a test that measures this while keeping other factors the same. My anecotally, my old Taylor 214 sounded fine in standard tuning, but HUGE in D standard, but no good in E standard with lighter strings. I assume it's largely that the lower tension allowed the top to move more freely, but still needed at least 12s to maximise that movement.

Interesting the Bourgeois I slightly fell in love with on holiday had a noticeable greater relief than my own HD28. My Martin is a really great sounding instrument, but the Bourgeois was something else. I may have an experiment with the truss rod...