Some help determing string length for a lyre (Looking for resources)

[Courtney Fox]

Hi all! I apologize in advance for the question dump. I suppose I don't expect anyone to sit and walk me through this, since it's a lot, but I'm looking for general resources to learn about these things.

So, I want to try my hand at making a lyre. I've got a fair music background but never made an instrument before, but I was given one as a gift and am delighted by it, and I want to try making some. I'm fairly stuck on figuring string sizes, though... I know it's going to be more complicated than "Stick a string on whatever." I'm assuming that each note frequency is going to have a string length that works best for it (and string thickness!) Is there a trick, or equation, or what have you to calculate this? Would I need to calculate ideal string lengths and base the instrument around that, or does it scale (Could I make a lyre that's very small, or one that's very large (for a lyre) or would that change the equations?) I'd like to be able to make a handful of sizes, but I'm unsure how that would change my string calculations.

And, possibly related, is there a particular recommended constant increase/decrease in string size as you go a note up/down? (I.e. a B is .5" longer than the string for C, etc). And, of course, figuring out what thickness string is ideal for which hz of each note....

Ultimately, I'm wondering if there's a really good source of literature on this, or a trick I can use to learn to do this efficiently and easy to scale across instrument sizes. I've poked around and found a little here and there, but not enough for me to feel confident in starting to build anything- Especially if I need to know if I should get my string lengths first, or if I can start carving the body of the instrument and rest assured that I will be able to figure out string lengths later after I know more!

(....Also, if anyone has a recommendation on where to source good strings from, or if I should go nylon or metal, I'm all ears)

[Bob Gramann]

You have good questions. I spend all of my time with guitars and similar instruments, but the principles ought to hold. This document (about guitar strings) tells you more than you ever wanted to know: https://www.daddario.com/globalassets/p ... _13934.pdf.

In the first couple of pages, they state the equation relating frequency, string length, string weight, and tension to each other. Given the equation, the note you want, and how long you want the string to be for that note, you can play with tension versus weight. There used to be a bit of mythology for guitars, like “all of the tensions ought to be near the same,” that doesn’t really hold. The reason that guitar strings are the sizes they are relative to each other is that they evolved to that over time by player selection. In the case of the guitar, the tension from string to string varies a bit—you’d never get to what is sold as a working set by calculation or guesswork on your first try. So, a good guess for your first instrument is to find one you like and copy it. After you’ve built it (or however many you need to build until you get there) and got it working like the one you copied, then you can experiment with changing parameters. All that is required to determine the string diameters on an existing lyre is a dial caliper.

And, if you’re lucky, someone who’s built some lyres will chime in and give you some good information.