String gauge calculation?

[vladoicho]

So, I've been playing a 4-stringer tuned in 5ths (Bb F C G) for some time now. I'm using regular strings from a 5 string set without the A and the results are pretty decent. Still, maybe if I can figure out more correct string gauges for this tunning, and actually find them somewhere, things could probably be even more awesome?

 

Do you know any website or whatever with a calculator or guidelines for calculating string gauges based on tuning and scale length?

 

I know that Circle K Strings is probably my best (and only?) bet for finding such specific strings, but the shipping rate of 35$ to where I live means that I probably won't become their customer just yet.

 

Anyway, at this point the question is mostly academic, but still if you have any info, I'd be thankful.

[MahaloVision]

The D'Addario website has a PDF on how to calculate string gauges. Pretty simple.

[isaac42]

All else being the same (same windings, etc.), doubling the string thickness, or gauge, halves the frequency. So, if you like your G string to be, say, .040, then you'd want the C to be .040*98Hz/65.4Hz=.060. The F would be .040*98Hz/43.65Hz=.090, and so on. For equal tension, each string should be 3/2 the gauge of the string above it.

 

However, not everyone likes equal tension. You might have to experiment to find what feels best for you. Another way to get close, and not as expensive as buying a lot of strings, is to look at sets and do the calculation from a close note. For instance, for the F, start with the E from a four string set. The e string from a light gauge .040 set might be .100. An F string the same tension as the E from that set would be .100*43.65/41.2=.106. .105 would be fine, and, in fact, some .040 sets use .095 for the E, so .100 would probably be fine, too.

 

If you're wondering where I'm getting the frequencies for the strings, I'm starting with A=440hz, the standard for most western music. A on a bass is two octaves down, at 55 Hz. In the equal tempered scale (again, the standard for most western music), each half step is the twelfth root of 2 (1.0594630943592952645618252949463) above or below. So, to find Bb, start from A=55Hz, then multiply by 1.059 (or as many digits as you want to use) to get 58.245Hz (using more digits, it approaches 58.27Hz, but I don't think that's a significant difference).

[vladoicho]

Awesome, thanks a lot!