Ideas for changing a diatonic harp tuning on the fly

[Brendan]

Good to hear you're home and back on this interesting project, Dom. On a couple of points in your last post:

"I find retuning chromatics much more tedious than retuning diatonics, each model seems to put the slide-in and slide-out reeds in different places. it's nowhere near as easy as a "draw plate" and "blow plate" like diatonics."

Once you know the rules, it's quite easy! The ones that seem initially tricky are the chroms with a criss-cross slider (where the reeds in a scale cross over on both top and bottom reedplates, and the slider holes are accordingly staggered between top and bottom rows). For retuning to an altered scale that repeats after every 4 holes (like Bebop, Diminished, PowerChromatic, any variation on Solo Tuning), this is how to do it:

Start with the top reedplate in hole 1 blow. Get that correct, then count up 4 reeds to the right and retune to the same note an octave higher, then 4 reeds to the right of that. Then start on holes 2, 3 and 4 and do the same: count 4 reeds up and it will be the same note, an octave higher. Then do the draw reeds with the same rule. Then move onto the lower reedplate and use the same rule. It's quick, because you have the pitch of the initial note in your ear, and so you can quickly hear when the higher octave versions of it are coming into tune.

Unfortunately this doesn't work out with tunings that repeat after every 3 holes (eg. Wholetone/Augmented), or ones with variations in each octave (like Richter, PowerBender etc). With them you need to make tuning diagrams and follow them carefully!

"I haven't fully given up on a drawplate turboslide either. After playing with it a bit more I think the stability problem has to do with where the magnets are placed over the reeds. I have more design/rapid prototyping freedom than Jim did, hopefully I can whip something up next week."

Jim did do some initial work on a short drawplate Turboslide, in order to enable magnet bending on the top 4 holes in Richter tuning. However he had the mini Turboslide moving in slots cut in the comb tines UNDER the draw reedplate. But it never came to fruition. No doubt it would be hard to get it airtight...

[triona]

Here you have the layout of a chrom with straight slide and one with zig-zag slide in comparison:

Chrom, C solo, straight slide
All notes of C on the top reedplate, all notes of C# on the bottom.
Any blow reed is located besides its respective draw reed.



obere Stimmplatte = upper reedplate, untere Stimmplatte bottom reedplate
arrow up = blow, arrow down = draw, slide position = self evident

Chrom, C solo, zig-zag slide
Notes of C and C# interchanging from top to bottom reedplate.
Blow reeds and draw reeds in each hole besides each other on the same reedplate.



yellow = blow, green = draw, Schieber frei = slide out, Schieber gedrückt = slide pushed

Jim did do some initial work on a short drawplate Turboslide, in order to enable magnet bending on the top 4 holes in Richter tuning. However he had the mini Turboslide moving in slots cut in the comb tines UNDER the draw reedplate. But it never came to fruition. No doubt it would be hard to get it airtight...

I really can imagine that. I guess without any gasket like a shaft seal ring or similar there is no chance.


dear greetings
triona

[dominico]

For retuning to an altered scale that repeats after every 4 holes (like Bebop, Diminished, PowerChromatic, any variation on Solo Tuning), this is how to do it:

Thank you! I wound up stumbling into a more rough edged version of this procedure converting a Solo Tuned EastTop Forerunner to a Diminished Tuning. I did it with Blutak. It does indeed play well! It took a bit of time but I imagine I will get faster at it the more I do it.
I do eventually want to create a 10 hole chromatic harp in Paddy Richter Extended, so this will come in handy.

Back to one of your earlier suggestions about blu-tak and magnetic coverplate hardware... I like this idea a lot, its quite genious and made very practical with the idea of quick detach-reattach cover plates. I've gotten used to using blu-tak lately and I think this could be a pretty slick way to go about it.
Forgive my ignorance on the magnetic coverplate implementation, do you basically superglue neodymium magnets over the coverplate screw hole or is it more involved than that?

Jim did do some initial work on a short drawplate Turboslide, in order to enable magnet bending on the top 4 holes in Richter tuning. However he had the mini Turboslide moving in slots cut in the comb tines UNDER the draw reedplate. But it never came to fruition. No doubt it would be hard to get it airtight...

I had thought about putting the magnets inside the comb over the draw plate as well, but that would not only complicate the comb design but also the slider design as well. The magnets work just as well below the draw plate provided they are given a spacer to slide across so the reed still has space to move. Also, the magnets pull the reed slightly away from the slot rather than closing it, so there is no risk of the slider choking the reed like what sometimes happens with the blow plate slider.

I was able to print a successfull "underplate spacer"; I've started working on a draw side slider design, the magnets will be positioned somewhere between the halfway point of each reed and the base. I'll play with the best placement for each reed.
If I can get the drawplate slider to actually work (and sound good and stable) then I have a monster of a plan for my Seydel Nonslider

Regarding the thought vein that maybe a chromatic platform is best for these ambitious goals: I went ahead and ordered a Trochilus/Bushman Gamechanger in A/Bb. We will see how mod-friendly of a platform it is. The design looks very wonky; everything in an odd shape at odd angles; and I'm not sure I like the "Jetsons" aesthetic. Those things aside, at least in pictures it looks only slightly larger than a diatonic, and to me that's its biggest selling point. I like the price of the 10 hole EastTop better, I just wish they were able to get it into a slightly smaller package and offered it in more than one key.

[dominico]

So Dominick... A combination of Blu Tack on the reeds with magnetically-attached covers should give you a pretty effective way of changing between tunings in 10 seconds or so, on the same harp. It's not exactly instant "on the fly" between licks, but certainly usable for situations where you want a particular tuning for a song and don't want to carry two harps.

I took your suggestion and started making magnetic coverplates for my Seydel 1847s.

viewtopic.php?f=9&t=948

and while watching your video I was inspired to build my own version of a Slipslider as well!

viewtopic.php?f=9&t=949

My drawplate turboslide project got a bit side-tracked while I built a slipslider instead, but I'll be back on it soon.

[EdvinW]

As a reed swings back and forth in its slot, a turboslide works by pulling at it when it get's far out on one side. This results in the reed spending a little more time on that side, which lowers the frequency by which it swings.

Why, precisely, doesn't a turboslide work for the draw reeds? It might be because the pull at the draw reeds result in too much gapping which makes the reeds unplayable, but I haven't experimented with this myself. I suppose moving the turboslide further away, so that the reeds mostly feel them when they swing far out from the slot, has been tried and eliminated as a possibility as well.

If pulling the draw reeds further out doesn't help, would it be an option to place tiny tiny magnets on the draw reeds? If each reed has a tiny magnet that's orientation is opposite to that of the turboslide it would instead push it into the slot, like the blow-reed turboslide does.

It's not completely the same effect though. The blow reeds experience a stronger magnetic field the further they are pushed into their slot, while magnetised draw reeds would experience a stronger force further out.

I think this would result in the reed now spending a shorter time on the side of the turboslide, so that the frequency would increase rather than decrease, but I'm not sure what the effect would be. It would be interesting to hear about.

Of course you would have to retune the reeds to compensate for the magnets, but there are, apparently, really small magnets out there. After a quick search I found this site: https://supermagnetman.com/collections/micro-magnets

If the magnets have a density of 7.5 g/cm³, their cubic quarter-millimetre magnets should weigh in just over a milligram. Their smallest magnets, currently out of stock, are just 0.2 mm and should be even lighter, somewhere around 600 µg.

I'm not at all confident it would work, but with all the experimentation going on some of you might think it interesting to try.

[Brendan]

Interesting ideas as always, Edvin...

I have some of these tiny magnets, and they attract well to Seydel steel reeds. I was looking into using them as reversible tuning weights: similar to the repeat-Blutak idea, but faster. Mixed success in that respect.

In your application they would need to be glued in a precise point on the reed, and with pretty strong glue to stop them flying off the reed when encountering the opposing magnetic force of the Turboslide.

Good luck with that! I feel this could be a case where theory and practice are two different things... But I hope you try it and prove me wrong

[dominico]

The Seydel All Minor proved that magnets can change the pitch of the draw plate reeds. They attached them to the cover plate.
https://www.seydel1847.de/SEYDEL-INNOVA ... INNOVATION

What I am basically doing is trying to is get the draw magnets side into a slider format, get the right magnet strength and positioning, and somehow fit it all within the space confines of the cover plate.

I just today discovered that the turboslide magnets are much bigger than I thought they were, they are sunk into to the grub screws by nearly 3mm. I thought they were 2mm x .5mm, turns out they are 2mm x 3mm. I should have tested their strength to begin with. The magnets I was using were weaker, and I could at best get them to lower a semitone. Now I'll be using strong magnets, which unfortunately exacerbates the space problem a bit.

[FingerSinger]

…
I have some of these tiny magnets, and they attract well to Seydel steel reeds. I was looking into using them as reversible tuning weights: similar to the repeat-Blutak idea, but faster. Mixed success in that respect.
…

I’ve just received a parcel of small magnets i’ve ordered to try exactly that - using them instead of blutak retuning. it seems to be working quite well.
I’m still thinking if it’s possible to somehow do that really on the fly though, with a click of the button or lever.

[Brendan]

Aren't magnets wonderful? Especially the small powerful neodymium ones we have now, in all shapes and sizes.

I don't believe in any kind of god, spirit, essence whatever. But magnetism is a kind of magic for sure! Even though science might explain it logically, I never get over the wonder that these things can attract or repel other objects through space.

And not just with an obvious strong effect on your tabletop. It's becoming increasingly clear that the earth's magnetic field is sensed via infinitesimally small quantum effects in the brains of birds to guide their incredible migrations over thousands of kilometres around the globe.

https://www.scientificamerican.com/arti ... -navigate/

We're very lucky that one of the major harmonica manufacturers chose to make their reeds in magnetically responsive stainless steel. Thanks SEYDEL!! And thanks to Dr. Jim Antaki for discovering the very cool musical effects small magnets placed at appropriate positions above steel reeds can have.

[dominico]

Indeed! Magnetism itself is super handy, and now with the availability of small, powerful magnets and the fact that people can now basically have an affordable rapid prototyping center in their own home, their are a lot of cool new uses for them emerging as well.

After playing with these things and Seydel's magnificent steel reeds for a while I've become convinced there is some untapped potential here as well. And definitely if it weren't for Jim Antaki I wouldn't even have thought to try to make a project like this work. I just wish he would respond to his email

If you want to see a video update of where I am right now in this project, I have a crude prototype of the draw side which drops the B to a "Bb" to make a minor tuning and minor chords.

https://youtu.be/pDx_m-v-r7w?si=x3EgmkfF6A1tgkWl

Video is 7 minutes long, I apologize I talk too much. I do play it a bit but I'm holding the bottom coverplate on because my set screws are currently too big to proper fasten the bottom coverplate.

Advice I could use: I only have 5mm of clearance to work with, plus the space needed for the draw reeds ro be able to oscillate, ideas about how to make the thing more compact are welcome. I will need to work a slide spring into it somehow at some point that would ideally drive an upper and lower slide at the sane time (or maybe independently, maybe it would be cool to flip between natural minor and Dorian tunings )