'Straight Through' Tuning Pegs

[KarmaShaman]

Hello, first post here. I have joined because in 2014 I plan to build (or perhaps seriously mod) an instrument to loosely emulate the mechanics of a sitar, with a focus on the sympathetic strings being a primary feature.

The design ideas are purely in my head at the moment, and there are several considerations. However one of the idea I have would be best suited in using 'straight throuh' tuning pegs, (ie; not the right angled, geared pegs found on guitars, bass etc) as you would find on a violin.

As I'm probably leaning towards high-tension steel for the resonating strings, I'm hoping for some comments from others. Would this style of peg be inappropriate for steel strings? Bear in mind that they won;t see as much stress as regular setups, because the strings will never be 'plucked' other than when tuning them.

[Workingman]

Stiendberg makes straight through pegs that are designed for high tension.

[Prostheta]

Agreed. Their planetary gearing gives them a large turn ratio also which is excellent for tuning stability and adjustment. Something like 40:1? Certainly better than 1:1 like simple peg tuners :-)

It's a lot of weight, especially if there are many sympathetic strings like a harp.

For sympathetic strings, tuning is probably not that important on the basis that they will only vibrate in sympathy with related frequencies actually being played, plus a slight dissonance is probably only be a good thing in that kind of instrument.

I'm not sure how woods would hold up to direct tension over time. Even Ebony would wear or be subject to cracking in time. Perhaps some kind of artificial material similar to an artificial Ivory or tough plastic might work better? Brass might be pretty easy to turn into friction pegs but very very weighty also.

[Prostheta]

This looks interesting:

http://leeharps.com/?p=205

[KarmaShaman]

Thanks for the replies. I have decided to go for conventional, geared pegs, and have just purchased a cheap set (this is for a prototype, so better quality gear will follow if and when the design is proven to work).

Prostheta, you raise some other comments which I would like to expolore further. With regrads to the sympathetic strings being slightly out of tune, thus creating a dissonance, I would have thought that this is what I wanted to avoid at all costs. To my mind, the resonating strings would need to be as closely tuned to the played strings as possible, thus allowing for maximum vibration on the set that are clearly going to need a lot of stimulation without touch.

Incidentally I will also be building a saddle that promotes buzzing, using the principles of a Jawari (a sloping shape rather than a sharp cutoff saddle that is common on guitars). In fact I'm thinking a hard steel tube around the overall size of a finger slide, sliced down the centre, would be perfect.

You speak of woods under direct tension perhaps not holding up. Not sure what you mean here, are you talking about the absence of a truss rod? I'll need to do a bit of experimenting, but ideally I'm hoping that I can calculate a string length of around 1ft/30cm (very approximate figure here) to achieve the sympatic notes I require. So, half of a guitar's string length, will that result in half the tension, or twice the tension? I was thinking of using 3-layer plywood (that's likely to make many readers cringe!) for the first instrument.

I'm quite flexible on the string types, and maybe I should consider nylon for the string material, as I probably won't be incorporating a truss rod into what will be my first 'luthier' type project ever. However i would hve thought that steel would 'sing' a lot better on the sympathetic part of the instrument.

[Prostheta]

I'm certainly not any kind of expert on acoustic instruments, especially not those with sympathetic strings. My basic understanding is that the sympathetic resonance has a significant falloff when the natural resonant frequency of the sympathetic string varies from the motivating one. It is worth experimenting I would have thought. Slight variations will create a pleasing natural chorus which is a good thing for an expansive sound.

Strings do have one primary resonant frequency however the same as a vibrating string has overtones and harmonics, so do sympathetic strings. I guess in many ways this is not too dissimilar to a strung instrument feeding back through amplification or even a sustainer.

I was more thinking about wooden tuning pegs under the tensions and rigours of steel strings. I'm sure that they'll work but not sure about the longevity. Nothing stopping you from using a combination of both!

Sounds like a very interesting project. I'm looking forward to seeing you develop your ideas.

[SwedishLuthier]

My choice for the sympathetic stings would have been something lite this:

Several reasons:

- You can and will need a tuning wrench, meaning better force and better precision

- proven

- very size economic, you can place the strings very close to each other (i think this is similar to what danolectro used on their electric sitars in the 60s)

- very good price