Octobass Hurdy Gurdy

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Octobass Hurdy Gurdy

Postby Michael Deazley » Sat Apr 22, 2017 12:11 pm

I am still in the design stage of this project, which is for fun and novelty, not for the production of a practical instrument.


Last week I learned of the Hurdy Gurdy. As I had already been looking into building a double bass, I had the idea of making a bass-sized hurdy gurdy. Then the other day I discovered the Octobass. I couldn't help but think that the octobass would be easier to play if it was set up something like the hurdy gurdy.

So I am planning on starting a cheap (and therefore horrible-sounding) prototype of an octobass hurdy gurdy. I figure a treadle-powered flywheel would be better than a crank for such a massive instrument, and when it comes to the keys I was thinking a simple hydraulic button system instead of either keys or levers.

On existing octobass', the strings are over eight feet long. The tuning I want is: C0, G0, and D1. I am obviously not looking at sticking with a traditional classic construction, so I could possibly scale it down a bit, but I don't know enough about strings to know how to approach it either way (which is how I wound up here, looking to learn). Of course, I am continuing to poke around myself, but if anyone more experienced has advice on a starting point to reach those low notes, it would be greatly appreciated in moving forward with my prototype.

If my prototype turns out promising, I may add more strings to increase it's range up through the double bass and cello, possibly even higher. But there is no point in adding so many strings that it resembles a harp or piano instead.
Michael Deazley
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Re: Octobass Hurdy Gurdy

Postby Jim McConkey » Sat Apr 22, 2017 2:06 pm

Welcome to the Forum, Michael!

I know nothing about such gigantic strings, but you might want to contact the Aquila string company, who seem to have researched the strings and have made historical copies:
http://ricerche.aquilacorde.com/ricerch ... -octobass/

Good luck! This should be a fascinating project. Please post pictures here as you go!
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Re: Octobass Hurdy Gurdy

Postby Liam McGillivray » Sat Feb 03, 2018 6:32 pm

I much applaud your willingness to create something untraditional like this. I will be happy to see it. Seeing projects like this is what I live for.

The hurdy-gurdy is an interesting instrument, and it's surprising that there aren't more instruments that borrow it's wheel feature to drive the strings. The only other that I've seen is the Apprehension Engine. However, I did consider having a hurdy-gurdy-style wheel on my project, which could have made it somewhat similar to yours, only it would have been closer to an upright bass in it's lowest note, only 36-38" scale length, and electric.

Something that I suggest for your instrument is you make it sit on it's back like a table (or a pedal steel guitar), rather than upright. This would make it easier to play, and have all the controls reachable.

I doubt that it would work (even as just a toy) with such low-quality hydraulics. To make it work, you will probably either need (almost) bicycle-quality hydraulics, or solid mechanical keys. I don't know if the treadle powered flywheel will be strong enough, as I don't know how much resistance hurdy-gurdy wheels have against them. However, a crank will give you better control, and it wouldn't get stuck like a treadle would.

Another problem I see it that if you have 3 strings, but only one wheel, then all 3 strings will be played at the same time. Even on bass guitar, full chords are generally not played except for on the upper frets, because such close intervals sound so muddy at such low frequencies. This would be worse for the even lower tuning that you're going for, but maybe it would be fine If you just want it to be a toy. The solutions to this are to either have dampeners to mute the other strings (or just use your fingers if you're not using them for the flywheel), have 3 different flywheels with different cranks, have a gearbox to switch between 3 flywheels, or just reduce it to a single string instrument. If you don't do any of these solutions and the strings are only playable at the same time, then all I suggest is that the strings are at-least an octave apart in tuning.
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