Notes from the Workshop

A space for players interested in my specialist harmonicas, alternate tunings, instructional material, recordings etc to ask questions and share information, experiences, videos etc.
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Brendan
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Notes from the Workshop

Post by Brendan » Mon Jul 06, 2020 5:32 am

After a long hiatus the Rn'D bug has returned, and I've recently been spending time happily tinkering away in my workshop again.

The main idea I'm exploring is how to make a chromatic harmonica with a different air shifting mechanism to the conventional front mouthpiece and slider. For inspiration I'm going back to some ideas from the early days of harmonica development, in the 19th century.

The very first chromatic harmonica had a rear baffle which selected between upper and lower reedplates:
https://www.patmissin.com/patents/DE19221.html

It was later 'reinvented' and released as the Machino Tone Chromatic in the 1950s:
https://chromhistory.wordpress.com/2019 ... chromatic/

I've known of this intriguing chromatic for a long time, but recently got to hear it in action, played by the Japanese ex classical world champion Arinori Inagawa. He bought one on eBay and showed it off in a couple of videos:

https://m.facebook.com/story.php?story_ ... =607508388

https://www.facebook.com/arinori.inagaw ... 873143389/

The main advantages of using some kind of reedplate selector at the rear are that you can use a thin comb (diatonic thickness of about 6mm, without a central divider), lose the mouthpiece, get your mouth closer to the reeds, and possibly avoid valves (the Machino Tone has none). So it's worth going back and testing some of these old designs again, I think.

However, as the old saying goes 'There's no such thing as a free lunch', and they all have drawbacks of their own. It's not necessarily about whether a particular design works to shift your breath between reedplates efficiently or not - though even that can be tough to achieve without air leakage.

Ergonomics could be one problem area: the action required to operate the mechanism is perhaps not as fast or convenient as a sprung slider. Noise might be another; as you can hear on the Machino Tone, it's difficult to make something that hits a surface fast and hard work silently! Complexity, durability and expense could be further factors that mitigate against alternative designs.

Normally there is a very good reason that the status quo is as it is! After trying this, that and the next thing, in the end I might be forced to follow the historical pattern and settle with the conventional front slide design.

But it's fun trying to go back to the future and update ideas from the 19th century. If I make significant progress I'll let you know.

Lizzy
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Re: Notes from the Workshop

Post by Lizzy » Mon Jul 06, 2020 12:10 pm

Brendan..you are describing the reason why i often prefer the diatonic before the chromatic...to long distance between mouthpiece and reed and to thick comb and other small things. You have to choose between a big chromatic or a small diatonic and almost nothing between. Even if i emboss, reshape and gapping the reeds on my chromatic i still prefer the response from my diatonic. I wish it would not be that way but it is.

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Brendan
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Re: Notes from the Workshop

Post by Brendan » Mon Jul 06, 2020 1:29 pm

Early chromatics such as the ones on those links avoided the long distance to the reeds. I hope I can update their designs for a new model along similar lines.

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triona
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Re: Notes from the Workshop

Post by triona » Mon Jul 06, 2020 4:16 pm

Looks interesting. And I guess the old patents might have run out now. But as I know you, you could evade them by some substantial improvement anyway. :lol:


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Re: Notes from the Workshop

Post by harpdog123 » Sun Jul 12, 2020 2:50 am

Very intriguing out of the box concept Brendan! Hope you can make it work!

David Pearce

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Brendan
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Re: Notes from the Workshop

Post by Brendan » Mon Jul 13, 2020 2:24 pm

@ Malarz: They're working for me today, hopefully for you too?

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Brendan
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Re: Notes from the Workshop

Post by Brendan » Wed Jul 15, 2020 8:54 am

Hmmm... I have a rear slider chromatic working well in terms of selection of clear notes, but the sound is not as good as the Machino Tone, or a normal chrom.

It sounds rather constricted. I'd normally assume that was because of the 12 partitions in each coverplate, but since the Machino Tone has them too and sounds loud, I'm puzzled!

However I'm using a different comb design and fully valved reedplates, so perhaps one or both of those is the cause...

Will keep tweaking and see if I can improve it.

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Brendan
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Re: Notes from the Workshop

Post by Brendan » Sat Jul 18, 2020 1:20 pm

This is basically the design I've been exploring. Inspired by the Machino Tone, but with a rear slider instead of baffle. Its attractions are:

1. No front mouthpiece or slide assembly. This means the mouth is closer to the reeds, always a good design principle.
2. Slimmer overall thickness, since the comb can be reduced from 12mm to 6mm.
3. The rear slider only needs to be airtight on one side, abutting the rear. No need for it to slide in a channel, with the issues that can create.
4. Rear slider allows easy cupping for sound shaping.

I've got it working well in terms of note selection but found some negatives:

1. Constricted sound - not sure why. I think it's the cover compartments, which are necessary for this design.
2. Our old friend Helmholtz Resonance Coupling. Interference from the cover compartments messes with the pitch of the reeds, especially in the top octave. It flattens the pitch slightly, and makes draw-bending on high reeds (eg. hole 11 on a C chrom, the A and Bb notes) impossible.

It's not game-over for me with this design, but it's not looking promising at this stage.
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Roverharp
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Re: Notes from the Workshop

Post by Roverharp » Sun Jul 19, 2020 3:37 am

Haha. Looks like the same problem i’ve been having with my own designs. So, there are partitions build into the cover plates? I think those can cause a problem but one different than what you you mentioned. Let’s deal with that first.

In my experience the restricted sound is down to the air being routed out the rear of the harp. I’ve built some harps that didn’t have cover partitions but did have porting out the back. I also noted such a sound. Seems the more robust sound comes from directly over the slot as the reed swing through it. When this is prevented the air seeks another point of exit. Routing it to rear ports does work; just not as rich sounding as the point where the sound is generated.

The main issue with placing partitions is that it can sometimes cause ‘de-coupling’ of the reeds used in a bend. Instead of working together it becomes difficult to hold a bend and both reeds go off squealing in opposite directions. This is pretty common in the Suzuki Overdrive. Bent notes occur as an interaction between reeds. (Even reeds in addition to the two reeds in a chamber seems to offer more stable bends).


Brendan, if you like let’s pow-wow this week. I should have something to show for the design experiments i’ve been trying. Also lots of hiccups that you can help resolve :)
Last edited by Roverharp on Sun Jul 19, 2020 12:22 pm, edited 1 time in total.

Roverharp
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Re: Notes from the Workshop

Post by Roverharp » Sun Jul 19, 2020 8:04 am

Double post
Last edited by Roverharp on Sun Jul 19, 2020 12:21 pm, edited 4 times in total.

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