Using the Trochilus as an x-reed platform

Anything apart from the two mainstream default harmonicas (Solo-tuned fully-valved chromatic, and un-valved Richter 10-hole diatonic). Alternate tunings, different construction, new functionality, interesting old designs, wishful-thinking... whatever!
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Using the Trochilus as an x-reed platform

Post by dominico » Mon Apr 29, 2024 5:56 pm

Hey folks,

I've started on another project and am looking for advice on a few decisions to make.

The Trochilus gets 40 reeds into something "nearly" as small as a diatonic at least something that would be "pocketable" if it weren't for the slide.

I've thought about what to do with that slide, redesign it so it sits somewhere else, out of the way, or potentially get rid of it all together.

I realize I could simply retuned it and use the slide for when I want blow bends, but if I could convert it to function like an x-reed style harmonica it would no longer need the slide.

My initial plan is to:
  • Retune a couple holes to various 3 or 4 reed configurations to test.
  • Replace the slide with a gasket under the mouthpiece
  • Design and print overvalve plates
  • Decide on 3 or 4 reed x-reed strategy
  • Add the valves to the reedplates / overplates
  • Retune the rest of the harmonica based on chosen strategy
  • Assemble the thing
I made an initial, very generic reedplate overplate, just to test the fit. I'll wind up enlarging the reed slots (or closing off certain slots completely) depending on which directions I wind up going with the design.

First trochilus overplate print: fitment test
trochilusTestOverplate.JPG (39.49 KiB) Viewed 981 times
Decision 1: 3 or 4 reeds per hole?
Pros for a 3 reed configuration: one less reed to deal with, potentially more airtight.
Pros for a 4 reed configuration: unlike the 3 reed configuration, the active draw can bend independently of what the active blow is set to, since it interacts with its own x-reed. Cons is dealing with 10 more reeds, possibly more resonance, airflow issues to deal with.

I have not considered preserving the ability to overblow in either of these designs. I'm guessing in both cases the overblow would actually result in a lower note since you would be interacting with the lower draw x-reed.
Rob's discussion here is making me wonder if this is something I should consider:

Decision 2: what to use as a gasket material under the mouthpiece
I've thought about simply printing a plastic insert here, but I'm open to other thoughts.

Decision 3: Which material to use for valves?
I am an avid half valve player. For the most part I use Seydel's PT Gazell valves. I'm guessing they won't work here for a number of reasons, one of them being that they are heavy and will probably fall when installed where they need to underhang a reed.

I can't find a very good supplier in the US for chromatic valves, or maybe I am just looking in the wrong place. If I wanted to make my own what materials would you suggest? Or maybe help me find a good chromatic valve supplier :-)

Decision 4: Which valves to attach to the reedplates vs the overvalve plates?
Theoreticaly I think I could install them all to the over or underside of the overvalve plate, and make the plate at least a couple mm thick to give the reeds space to swing. I'm looking for advice on which valves make more sense to add to the overvalve plate rather than directly to the reedplate.

Thank you all!

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Re: Using the Trochilus as an x-reed platform

Post by Brendan » Tue Apr 30, 2024 12:43 am

As you say Dom, the Trochilus should provide a nice platform for your X-Reed experiments. Not just because of the slim comb, but also because it has excellent reed/slot tolerances - which is important for such demanding harps.

I now have one and checked the reedplates under my microscope. They are extra thick (1.2mm), and the reeds sit centrally and very closely in pleasingly sharp-edged slots. Well done to JDR for their fine engineering precision in this vital area of harmonica performance.

Seydel sell sets of their chromatic valves, which of course work sitting on the lower plate or hanging from the upper one against gravity. I'm pretty sure they have stocks of them in the USA and can ship to you quickly. Here's a link with US dollar payment: ... -FANFARE-S

Each has its attractions, as you say. I think only you can decide what's best for you.

I've made a lot of gaskets over the years. The quickest and most effective way I've found is to lasercut them from single-sided adhesive foam. Neoprene cuts well, and comes in different densities.

Hope that helps. I haven't tried using the Trochilus as an x-reed platform, so am interested to hear how it goes 🙂

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Re: Using the Trochilus as an x-reed platform

Post by Brendan » Tue Apr 30, 2024 10:04 am

Looking at your OverValve Plate:

You'll need to add pockets on alternate slots to accommodate the wider area where the reed is welded onto the plate in order to get a good seal.

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Re: Using the Trochilus as an x-reed platform

Post by ousingp » Wed May 29, 2024 5:02 am

It should provide a good seal while allowing for smooth movement.geometry dash Decision 3 is tricky, but perhaps exploring thinner materials like Mylar for homemade valves could be worth a try. Lastly, for Decision 4, attaching valves to the overvalve plate seems logical to me, as it would simplify assembly and maintenance, but test it out to see what works best for your design.

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