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**alfonso** · 02-21-2009, 08:49 PM

Originally posted by weasel_key View Post

Hello everyone!

This time I want to comment on a project I have in mind and I want to build.

I said a little involved ... I have a very basic keyboard for beginners. Has few octaves and only has analog output and not to MIDI ...

What this requires is to use a circuit that is capable of converting analog audio signals to the MIDI protocol and thus can be used in computer ...
This circuit detects pulses identifying the fundamental ... and then through other stages of the circuit as an analog to digital converter and etc. .. is how it works and communicates the computer and the keyboard.

I listen to other suggestions ... perhaps there is some alternative that I have not had any in mind.

I have seen a circuit that I have no details yet ... would have no problem getting the necessary components for arming myself ...

I would like to use my keyboard to the PC using a program called Sinthesia.

I appreciate the information I can provide both technical circuits ... or you can ...

Greetings and thanks for your time.

Converting a sound to MIDI is something that will have very limited results compared to the use of a MIDI keyboard. First limitation is polyphony, I'm not aware of any device able to effectively track in real time more than a single note to detect the pitch. then you have the latency proportional to the wave length, same problem with guitar MIDI converters...then all the derived dynamics are very poorly represented, and forget many other useful possibilities of MIDI control.....Some MIDI keyboards are really very cheap....

**weasel_key** · 02-21-2009, 10:56 PM

Originally posted by alfonso View Post

Converting a sound to MIDI is something that will have very limited results compared to the use of a MIDI keyboard. First limitation is polyphony, I'm not aware of any device able to effectively track in real time more than a single note to detect the pitch. then you have the latency proportional to the wave length, same problem with guitar MIDI converters...then all the derived dynamics are very poorly represented, and forget many other useful possibilities of MIDI control.....Some MIDI keyboards are really very cheap....

How about this circuit?. Do you think also has the problems that you just outlined? If I find a circuit that uses a fast microcontroller ... Could it work? or there is nothing in order to do what I want?

(That would be interesting electronic project, rather than a more professional, as cheaper to buy a midi keyboard ... just for that reason is what I want to build ...)

This is the circuit: http://kmt.hku.nl/~pieter/HARD/A2MIDI/A2MIDI.html

Thanks a lot =)

**alfonso** · 02-21-2009, 11:33 PM

I'm not an expert in circuits, I'm here more to ask, but the project you linked is made to change control voltages, which are the system to operate vintage analog synthesizers, to MIDI...it has nothing to do with the conversion of Audio signals to MIDI.

**Enzo** · 02-21-2009, 11:45 PM

I agree, the circuit you link even says right in the first paragraph that it is designed to convert slowly changing voltages between 0 and 5v to MIDI control values.

This is not audio, has nothing to do with audio. A very sophisticated circuit could be made I am sure to detect frequencies of notes, but you still would have the problem of polyphony.

MIDI is not based on the audio signal anyway. A MIDI keyboard sends NOTE ON signals when you press a key, and then NOTE OFF signals when you release it. if you want a keyboard to send MIDI signals to a computer, it is REALLY a whole lot simpler to find a basic MIDI keyboard. Translating audio a note at a time into MIDI somehow will be very inefficient.

REally basic MIDI keyboards are around inexpensively even when new. There must be thousands of them in basements across the land, you might even get for free. Abandoned Christmas presents.

**weasel_key** · 02-22-2009, 01:09 AM

OK. I know that this circuit not only serves, and that is inefficient, (unfortunately for me, of course) ... in combination with another maybe. Actually, I do not understand very much the topic because recently I have to investigate ...

I have this circuit ...

http://www.usyd.edu.au/anaes/rpa/Loa...as/PCmidi.html

With this and a MIDI keyboard is supposed to be solved. Right?

I will try to investigate more, and if possible I will try to raise doubts that have arisen after investigating further ...

Greetings

**kinglaiho** · 02-24-2009, 08:33 AM

i think i am looking for a similar sort of thing....

i would really like to something similar to this: http://members.cox.net/ampage/triggers.htm

but my issue is getting from the piezo output to MIDI and then to my computer....

any ideas?

**Enzo** · 02-24-2009, 09:00 AM

Drum triggers are just that - triggers. they simply output a pulse with each hit.

MIDI is a communication protocol. You need the circuitry to communicate with. It is microprocessor based. Your triggers could possibly feed a cheap MIDI keyboard key matrix. otherwise, I think I would look for an old electronic drum brain. If ther are drum machines that accept triggers, then that would work as well, though I don;t know any of the top of my head.

**weasel_key** · 02-24-2009, 09:29 AM

Thanks for your answer... =)

I 'll see more in deepper the matter...

Greetings!

**kinglaiho** · 02-24-2009, 10:16 AM

Originally posted by Enzo View Post

Drum triggers are just that - triggers. they simply output a pulse with each hit.

MIDI is a communication protocol. You need the circuitry to communicate with. It is microprocessor based. Your triggers could possibly feed a cheap MIDI keyboard key matrix. otherwise, I think I would look for an old electronic drum brain. If ther are drum machines that accept triggers, then that would work as well, though I don;t know any of the top of my head.

so there's no way to convert the analogue signal (or a set of analogue signals) into midi?

also, when you say i could use a MIDI keyboard key matrix, you're suggesting i buy a cheap/old/crappy MIDI keyboard, rip out the keys and plug the piezo/s into where they used to be? that sounds like fun lol

**Hammnond man** · 08-02-2011, 08:44 PM

Anyone still browsing this site for answers to these questions, Call Ram Electronics, in New Jersey. Ask for Bruce and tell him what you want and where you are from. They are trying to design a product to convert analog to digital to MIDI. Thier number is 888-726-2440, toll free. If we flood them with the interest in a unit, without the cost going thru the roof, maybe we will be able to come into the 21st century with our long out dated analog equipment. I for one will nver sell my old Hammond organ, but want midi capabilities. Bill

**Enzo** · 08-03-2011, 01:12 AM

Hi Bill. MIDI kits for Hammond organs have been around a long long time. Basically add some extra contacts under the keys and a small board for the MIDI.

**Jazz P Bass** · 08-03-2011, 01:36 AM

MIDIfication Of An Organ

Check out these links:
General MIDI - Wikipedia, the free encyclopedia
http://www.jbwebserver.net/mforum/up...ication_of.pdf
http://en.wikipedia.org/wiki/MIDI_1.0

**Hammnond man** · 08-03-2011, 03:52 AM

Enzo, where can i buy what i need. Everyone i have contacted, tell me that as midi grew over the years, the so called midi conversion kits are no longer being produced. I only need for the upper keyboard, and foot board. The lower keyboard has been replaced with a Yamaha DX-7. I will be using a Tyros-3 for the controller. I also will be midi-ing (cableing) thru a Korg PA80 and a Technics KN 7000. All the sounds i'll need. I just want to keep the Hammond for the main keyboard. I was told to use a midi Hammond XK3 to replace the main. Thanks

**Enzo** · 08-03-2011, 06:21 AM

Ah, well they used to sell them all over, but it didn't occur to me they'd quit selling them. And getting one of the newer synth Hammonds isn't a bad idea. I think they sound pretty good and with drawbars and percussion and even key clicks, they capture the3 flavor. But that is merely an opinion, you may not care for them.

In any case, I don't know the RAM guys, so no criticism intended. But really, to do this sort of thing, trying to capture the note from audio to get MIDI is the wrong approach. AS we mentioned a couple years ago, MIDI signals are not just encoded audio. It is instructions to a sound machine. Included are: note on, note off, velocity, and other data. Now for an organ, we don't expect velocity. SO basically, key closures into a MIDI box.

The old MIDI conversions were just that, key switches. They made them for organs, they made them for pianos - you could have MIDI on your baby grand. You could put it on a concert grand too, but then you'd need someone to smack you.

You want it to do what you want it to do, I understand that. I am not sure just what the end is. If you have a DX7, it certainly has MIDI send. You kept the uppers, so you still get the Hammond. You are holding out to get the Hammond tier to send MIDI as well as the DX7? Or you'd rather not use the DX7 in general?

Have you seen this video? I don't have sound on my computer, so I can't tell you how useful it is, but...
‪MIDI keyboard conversion‬&rlm; - YouTube

And to roll your own, I'd start with an existing MIDI keyboard. FInd the most basic cheapest little "personal keyboard" that has MIDI. Little Yamaha PSR somethings maybe. You'd install extra key contacts under the keys and pedals. Probably the pedals is the best place to experiment first. Then wire those to the circuit board that was serving the keys on the Yamaha PSR. Voila, MIDI. Yes, it would be a boatload of work.

I don't like the audio to MIDI idea, because as others have said, polyphony is a problem, and what about playing chords? And your drawbars introduce a lot of extra notes. Even if polyphony is achieved, then playing a note with both 8' and 4' pulled out would send two notes on MIDI. That might be fine if you are sending to a Hammond type sound box, but if you were sending it to some other patch, having an octave over the fundamental all the time would be a pain, or so I'd think. And that was just the 16-8-4-2' thing. WHat happens when you have the 5-2/3 or whatever it is bar pulled out? In the Hammond, that is a nice overtone. But to audio detection, it is two notes. If you send that in MIDI to say a trombone patch, I'd think that would sound darned weird.

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