tkoehler1 wrote: ↑
Sat Aug 12, 2017 6:00 pm
guitarrista wrote: ↑
Fri Aug 11, 2017 4:10 am
This means a guitar would have to have a 613.5mm scale to have the same 11% lower tension as that from tuning a semitone down.
Thanks for the responses and thanks for the technical explanation guitarrista. I don't quite follow the math but I respectfully think that it may be incorrect. I would think if I put those strings on a 61cm guitar they would be far more loose and floppy. I admit I can't prove it but that's my feeling
Normal tension on my 630 are too loose and they get a little buzzy.
Unless as people have mentioned, there are other factors that have a greater impact than I think.
Also I've noticed a few guitars out there with 645mm scales, I never paid much attention as to why they were built to that scale, now I wonder if they are after that same feel.
Last and even more odd I think the guitar sounds better tuned down. The same volume but richer, fuller sounding.
Hi tkoehler 1,
Even if you use the same strings, at different scale lengths the feel will be different, because feel depends on tension and scale length, too.
7 kg tension feels fine at 650 mm scale length, but feels too much at 432 mm for instance. It is because feel phisically means the force you have to push the string sideways.
To understand this force one must consider that the shorter the scale, the fewer are the elastic particles in the string. The total elastic stretch of the string is the total of the elemental stretch units of these particles. A shorter string has less elastic particles, therefore less stretch and so less yield to your fingers. Mathematically written, sideways force is proportional with the reciprocal string length (1/L).
This is exactly why guitaleles are tuned to A. As their scale is 432 mm, which is 2/3rd of the normal 650 mm, with the same string tension (7 kg) they should be tuned a fifth higher, to H, not A. (2/3rd string length is the 7th fret, i.e. the fifth diatonic step.) Still, if you tune a 432 mm guitalele up to H, you'll feel that its strings are too tight. This proves that feel - sideways pushing force - is inversely proportional with the scale length. With calculations it can be shown that if you reduce scale length to 2/3, the sideways force remains the same if you tune it to a fourth diatonic step higher instead of the fifth. Lengthwise pull of 432 mm guitaleles is only about 6 kgs, still their feel is the same as a 650 mm guitar at 7 kg pulling force.
As you'll just see, in reality, the situation is a bit more complicated.
Let's consider the string sections that are close to the saddle. The string pulling force there is the same as it is in the middle of the string. It is because longitudinal force spreads evenly along the unimpeded string. Still, if you want to push it sideways, or pluck it near the saddle (or nut), it will feel very tight and difficult to pluck, not so nice and soft as in the middle. Why? Because you must consider both sides of the string, i.e. both directions from the place of plucking. As the string is very short to one side, the elastic length in that direction is short, so the sideways pushing force is bigger than in the middle of the string.