Midi Conversion Of An English Concertina

[JDP]

Hello There!

 

We have been in MIDI interfaces production business since year 2000.
Besides the many other projects, recently we had a opportunity to convert an old English concertina with removed reeds to MIDI to turn it into "silent" instrument so that its owner can practice while travelling, without disturbing other people in the plain, bus, car etc.

The instrument became pure MIDI controller with three key layouts and air-pressure control over MIDI Volume.

User can change many things via SysEx programming, including key-note mapping, MIDI channel per side, default note velocity, pressure sensitivity and pressure response curves, pressure MIDI controller.

Here is a photo it:

 

 

I wrote an article about this conversion that can be downloaded from our site:

http://www.midiboutique.com/downloads/documents/midi_conversion_of_english_concertina.pdf

 

Any comments/requests are welcome!

 

Best Regards,

 

Jordan Petkov

www.midiboutique.com

Edited March 21, 2014 by JDP

[alex_holden]

Very interesting article, thanks for that Jordan. I am at the design stage in a similar project and have been planning to use a very similar arrangement of reed switches under the action board with magnets attached to the pads. From what I have read they are very reliable, reasonably cheap, low power and easier to interface to than either hall effect or optos.

[Don Taylor]

Jordan

 

Thank you so much for this, I have devoured your document with great interest. Very well done indeed.

 

I am particularly impressed with the way your design tries to keep the original look and feel of the concertina. I imagine that this approach will appeal to most of the folks on this forum.

 

I am sure that I will have lots of questions to ask once I have digested the document more fully.

 

Is there any possibility that your customer could give his or her opinion of the playability of the final result?

 

Regards

 

Don.

[Łukasz Martynowicz]

Jordan,

great pdf, thanks for posting.

I came across your site back in 2010, when I first started digging on MIDI instruments. Description of your mbe2 was a great source of initial knowledge of what can be done and have helped me in defining goals for my solution.

[JDP]

Thanks, guys.

 

Alex, if I had no requirement to make the instrument battery-powered, I may have used Hall switches instead of reed contacts.
Reed contacts are a bit tricky to be installed and position adjusted because of their fragile glass body, but once done, they are very reliable. Opto-switches are out of discussion as they require more power even than Hall switches (10-20mA per switch), and are sensitive to dust, plus they require more space and mechanical light beam interrupters, etc.

 

Don, I will ask the customer, maybe he will agree to share his opinion here.

 

Jordan Petkov

www.midiboutique.com

[alex_holden]

Have you experimented with different reed switches? They come in a range of sensitivities.

[JDP]

No, the space for reed contact was limited to by the size of air holes, so I had to go with the only type of 10mm reed contacts I could find (by Meder).

[Don Taylor]

So you kept the action board (buttons, springs, pads and holes) intact?

 

When you press a key then the same (or nearly the same) air flow would occur as for an instrument with reeds? Pressing three buttons for a chord would open three air holes and release more air just as it would on a traditional instrument?

 

I was wondering about conserving air in the bellows when playing multiple keys as you tend to run out of bellows capacity pretty quickly when playing chords. I was thinking about only having a single air hole, probably permanently open, sized to give a decent feel to the bellows and to conserve air capacity.

 

 

Don.

[JDP]

Yes, the action board, buttons, levers and springs, pads and holes were left intact.
In fact, the encoder boards cover the action board.
These boards are of same hexagonal shape as the action board.
5 of their 6 sides were sealed to board using silicone. Only narrow gap between sixth side and the action board (narrower than 1mm) was left. I'm not expert in bellow instruments playing, and my feeling was that the gap was was of right size to limit the air flow. The airflow limiting can be adjusted by either adding more silicone to make existing gap shorter, or removing silicone from 5th side.

The user liked it at once and did not report any discomfort about air flow speed.
If he reports such problem further, I will advice him what to do to add or remove silicone.