MIMF

Over the past about three years, I've been working on an instrument of my own design; I call it a "rotola." I've attached pix below.

The original design (what you see in the pix) had 16 strings; I've made some modifications since that I'll discuss below. The sounding body of the instrument is comprised of eight soundboard panels of sitka spruce steam bent and edge-glued into a cylinder. The nut (left) end has a solid walnut internal disc to which the soundboards are glued (not visible from the outside), capped by a external walnut disc -- also of eight sections (like a pizza) -- circumferenced with a brass rod that serves as a nut and into which the strings' end pins are anchored (small brass nails visible in the left side view). The tuning pin (right) end has a pinblock made of two layers of 3/4" Baltic birch plywood cut into eighths (again, pizza-like) to which the other end of the soundboards attach (also not visible from outside) and which is capped by a solid walnut decorative plate. Through the center of the entire cylinder runs a shaft of ash to serve as an axle and to bear most of the weight of the string tension. This axle rests in a walnut stand that serves only as a support and bearing surface within which the entire instrument may freely turn (see view from above). Outside this stand on the right is a solid walnut crank allowing the player to rotate the instrument (visible with a brass knob in the right side view). Strings are steel zither strings, 0.012", relatively lightly tensioned, while the bridges are purpleheart and can be moved to allow individual strings to be tuned to different pitches (compare to a koto or gayageum). Finally, the instrument is played by a highly curved steam bent ash bow with untensioned horsehair (see bowing pic) that wraps around the body to play up to half the strings at once.

In terms of the performance design of the instrument, it was conceived as a drone, especially as a monochord, to be performed by a single player. This prototype is quite a bit smaller than my initial vision -- think 'cello range as what I ultimately aim for -- with a lowest pitch of F above middle C, and with the steel zither strings its sound is very bright. However, as the strings resonate with each other -- both the bowed and the freely resonating -- it creates a rich (and loud) sound, as monochords are known for. With the moveable bridges, it can be tuned to play chords as well. My intention for the instrument was as a meditation aid, which I have found it to be delightful for. I am still working on creating a recording of it to share, but I have noticed that the impact of its rich resonance is very difficult to capture.

I'm posting here because I want to hear about others' experiences with similar instruments. Although this was an original idea, I know that there is very little that is actually new in the universe and would be unsurprised -- but delighted -- to learn of others on this forum who may have built like designs. Indeed, right around the time I finished the rotola (last November), I found a video on Facebook of a Brazilian band that had created a large, upright version requiring two players, performing with it several years ago https://www.facebook.com/watch/?v=975781312507473.

Once the rotola was complete and I could spend time experimenting with it, I discovered that half of the strings had wolfs of varying severity (violin family instrument performers will be familiar with this term describing notes that are especially non-resonant and make a kind of choking sound). After messing about with it, I determined that the issue was not limited to particular tunings or pitches, as it would be with a violin-family instrument, but particular strings, specifically, every alternating one. Of the eight with wolfs, two were still playable, so I removed the six with bad wolfs and the now ten-string instrument is even more resonant. I plan to experiment further with this and to address the issue in the next iteration.

I have posts on my personal blog detailing (for novices) my design and construction over the years; I can share links here if that is helpful, but I'll wait for requests, given that this post is already pretty long.

Please share with me your responses, thoughts, ideas, insights, etc., especially if you have built a similar thing!

view from above:

left hand view:

right hand view:

bowing:

A few weeks ago, I was trying to envision such an instrument to be played with a straight bow. This is amazing. Maybe you can post a video of it sometime, I'd love to see and hear it being played.

It’s sort of a reversed Hurdy Gurdy. Very cool.

Are you going to experiment with putting wolf tone eliminators on the offending strings?

Beautifully executed! Would also be the perfect accompaniment to a bagpipe chanter without the full volume of the pipes.

Just recently the Temu (Chinese cheap junk retailer) ads that have been annoyingly popping up on my tablet showed an instrument that looked a lot like it, or at least nearly cylindrical in shape, but I paid no attention to the ads. I may have a closer look the next time it shows up.

Try swapping some of your bridges or put a little paper padding under the strings on the bottom rim ("nut") to see if the wolf tones move. It may be a string seating problem more than a resonance problem.

It took me a bit to figure out how to get a video uploaded, but here's a link: https://youtube.com/shorts/8F_hU9M-fKw?feature=share. The instrument is tuned here to F, Bb, and C above middle C (I like quartal harmonies).

Thanks all for the encouragement! Despite its shortcomings as a prototype, I'm really happy about how this came out and am excited about the next iteration.

@Teresa Wiggins: One of the first things I did was to weave muting cloth between the tuning pin-side of the strings, because I realized that they were resonating inharmonically with the speaking length (honestly, I was a little embarrassed with myself that I didn't plan on that from the start), so hopefully, that would render wolf tone eliminators moot. That said, I did think about them and, if the seating issues I discuss below don't address it, I might experiment with them.

@Barry Daniels: Yes, I've been telling people it's kind of an "inside-out" hurdy-gurdy!

@Jim McConkey: I hadn't thought specifically about a chanter, but that's a good idea. I'm not a wind player, but I have one and might experiment with it. And I'd love to hear about that cylindrical instrument you saw, if you find it! Regarding the pads under the rim (I'm guessing you're referring to the brass rail on the nut end?), I hadn't thought of that, but I agree that seating is likely a good avenue for investigation. In an effort to keep the pitch as low as possible (and I was originally worried that the whole thing would collapse), I tuned the instrument with the lowest workable string tension. Also, the break angle over the bridges is pretty low, something I underestimated for a number of reasons. Plus, the body is not as perfectly cylindrical as I had hoped, so the radius I cut in the bottom of the bridges is sometimes more and sometimes less than optimal. Between these three issues, I think the bridges are not seating as well as they might. What confuses me, though, is that the pattern alternates between strings: the strings with the outermost tuning pins are fine, while the innermost all wolf. It might still be that seating will solve the issue, though, like there is still some inharmonicity arising from the different string lengths (consistent with Teresa's idea), but the sensitivity to it could be reduced with proper seating. If that's the case, one possible experiment would be to make new, higher bridges, with a tighter bottom radius (effectively putting feet on the bridges rather than a full-seat contact), and to raise the base pitch of the instrument; that's pretty labor intensive, so it won't be the first thing I try. I will, however, check the seating at the nut, as you suggest.

Not exactly what I remember or was was looking for, but I stumbled upon this tonight completely by accident, and you will it very interesting: https://www.youtube.com/watch?v=p2kJMPfFOX8

LOL -- Yes, I ran across that myself recently! Crazy. It does kind of scratch that itch, though, to figure out how to make a rotola that can change notes on the fly. (I have some ideas about that, but other problems beg solutions first!)

Can you press your fingers on the strings to get different notes?

@David - Think moveable hurdy gurdy tangents inside your drum if you want to change notes, but talk about complicated mechanics!

@Teresa - David's instrument is conceived of as a drone, but like the video I posted, he could play it with a bottle slide. Fingers will dampen the strings too much without frets, and the rotating strings won't be very comfortable on the fingers, either.

@Jim: Yes, that is the lines along which I was thinking. I'm able to imagine a chain of levers and sliding surfaces that would go from, say, a one-octave keyboard through to the interior of the drum which would then press tangents out against the strings, but I haven't CADed it out to see if it could actually work. At this point, I have other projects I want to try first before investing in such a complex and iffy goal.

@Teresa: Jim said essentially what I would have. Have you looked at the video yet? If not, that should illustrate the challenge more clearly.

@Jim: I see you are MIMF Staff; could you answer a question for me? Would it be okay and/or appropriate for me to cross-post about this (perhaps posting a link to this thread) on the string instruments section of MIMF? The descriptor, "If it has strings, post it here" (or something like that) felt like the rotola could be included. My goal would be to get as much feedback as possible on whether anyone else has built something like this.

Sorry, David, we really try to keep discussions to one place only. This is really the best forum for this kind of instrument. If you see a discussion in String Instruments where a mention of this would be appropriate, you can post a link back to this discussion, but please try to keep the main discussion here.

Yes, it makes sense, don't know what I was thinking, LOL.

@Jim: Thanks; glad I asked. Totally understand. I've been on forums where things get out of control (and readability) quickly! And I appreciate your clarification that this is the right thread.

@Teresa: No worries. I appreciate your thoughts!