MIDI Organ Console Project (Conn 652)

[John]

P. writes:

I just bought 4 of your [MIDI CPU] boards and would appreciate a little advice on configuration...

I plan to use them to convert an old Conn 652 console to run the Miditzer 260SP virtual theatre organ (after modifying the keyboards to provide 2nd touch contacts).

This then, will have 3 x 61 mote manuals, 2 with 2nd touch, 32 pedals and as many stops as I can reasonably persuade to fit along the existing stop rails plus a number of pistons, some of which would be assigned as generals and some divisional, plus 2 swell and one crescendo pedal.

What I had in mind was to use four boards as follows:
1 pedals / main swell / solo swell / cresendo
2 accomp manual / accomp 2nd touch
3 great manual / great 2nd touch
4 solo manual / pistons

Ideally, I would like to fit bar graphs to show the swell pedal positions but that is not a priority and I think I would need at least one more board for that anyhow. (I may modify the solo manual to provide velocity information to make the pianos more playable but if I do that I'll probably cannibalise an old yamaha keyboard for that...)

Does that setup sound reasonable or should I do it differently?

I'm unfamiliar with "2nd touch". What is it & how does it work?

Also, are the key switches or pedal switches already matrixed? Or will you be adding the matrix diodes, etc.

Please let me know, and I'll do my best to analyze your configuration.

The keyboards are probably matrixed in some fashion, as it currently uses digital keying but I will almost certainly be rewiring them to suit the new boards and fitting the diodes as required.
2nd touch is effectively another set of keyboard contacts operating on a different midi channel which close when additional pressure is applied to one or more keys. It is used to bring in another sound on one or more notes to make it sound as if the player has more than two hands and was originally introduced by Robert Hope Jones when he was building WurliTzer cinema organs. The MidiTzer software I will be running emulates a fairly large 3 manual + pedal WurliTzer known as the 260SP. The effect of 2nd touch can be likened to polyphonic aftertouch in most respects, although it is achieved in a different way.

I have had another look at the capabilities of the boards and changed my mind about the configuration, especially as 2nd touch will add only a very small amount of midi traffic, and I now propose the following configuration:

board 1: accomp manual (61 notes) / accomp 2nd touch (61 notes) (midi channel 1 & 5)

board 2: great manual (61 notes) / great 2nd touch (61 notes) (midi channel 2 & 6)

board 3: solo manual (61 notes - no 2nd touch) / pedalboard (32 notes) / main swell pedal / solo swell pedal / crescendo pedal (3
analogue pots) (midi channel 3 (keyboard), 4 (pedalboard) & 15 (analogues)).

board 4: stops / pistons (this will not accommodate all the stops of the 260SP but has more than enough capacity for the stops I presently have on the console. (midi channel 11 (54 stops) & 14 (25 pistons)). All the stops / pistons will be accessible from a touch screen on top of the console, so adding phyical stop switches to the console can wait until I have more money to spare!

The analogue pots may be better assigned to board 4 as they can generate quite a lot of traffic while playing expressively. What is the limit for the number of matrixed digital inputs that the board can reasonably accomodate with 3 analogue potentiometer inputs hooked up?

You can connect whatever combination of analog & matrix inputs you'd like. You're correct, however--lots of analog input activity on multiple inputs will reduce the matrix scan rate somewhat. But this shouldn't impact the overall functionality. I think you've got a good plan regardless.

If I decide to cannibalise my old velocity sensitive yamaha keyboard and use the guts to replace the solo manual (better control for pianos etc.), board 3 will be used for additional stop switches and the existing analogues. This would be better as it would reduce the midi traffic on a board which is also handling a keyboard.

The 61-key manuals will work well. I suggest arranging the switches in a 8x8 matrix. This will allow both the manual & the 2nd touch to be monitored by a single MIDI CPU, as you have suggested. I'll post an example wiring diagram as a response.

[John]

Here's the best way to wire two of the 61-switch matrices (manual + 2nd touch) to fit a single MIDI CPU.

The position of the switches and diodes can be swapped. But either way, the anodes must connect to the "data" lines, and the cathodes must connect to the "select" lines.

I chose control terminals 16-23 for data, because terminal #19 is unable to generate a select signal (see Table 9-1 in MIDI CPU Hardware Manual). Thus, two 8x8 matrices can be connected.

If this looks good, I can also post the configuration SysEx.

[stefanuk]

John,

You mentioned the sysex for this schematic, does it even need one, and is it published somewhere else?

[John]

Here's the sysex for the diagram above. Of course, the MIDI channels, note numbers, etc can be changed if we want. I chose MIDI channels 2 & 6 for the "great manual".

Update 2011-11-26: fixed config code for select lines so that notes are properly ordered. other posts in thread may not reflect the fix. -John

// Fixed Header
F0 00 01 5D 04 01
// Layer 00h
00

// CT 0-7: Matrix Select for "First Touch"
// Notes C2-C6 (36-96, or 24h-60h) on MIDI Channel 2
00 00 2E 02 5C 00
01 00 2E 02 54 00
02 00 2E 02 4C 00
03 00 2E 02 44 00
04 00 2E 02 3C 00
05 00 2E 02 34 00
06 00 2E 02 2C 00
07 00 2E 02 24 00

// CT 8-15: Matrix Select for "Second Touch"
// Notes C2-C6 (36-96, or 24h-60h) on MIDI Channel 6
08 00 2E 06 5C 00
09 00 2E 06 54 00
0A 00 2E 06 4C 00
0B 00 2E 06 44 00
0C 00 2E 06 3C 00
0D 00 2E 06 34 00
0E 00 2E 06 2C 00
0F 00 2E 06 24 00

// CT 16-23: Matrix Data
10 00 7F 00 00 00
10 01 7F 00 00 00
11 00 7F 00 00 00
11 01 7F 00 00 00
12 00 7F 00 00 00
12 01 7F 00 00 00
13 00 7F 00 00 00
13 01 7F 00 00 00
14 00 7F 00 00 00
14 01 7F 00 00 00
15 00 7F 00 00 00
15 01 7F 00 00 00
16 00 7F 00 00 00
16 01 7F 00 00 00
17 00 7F 00 00 00
17 01 7F 00 00 00

// Fixed Footer
F7

[stefanuk]

OK,

I get the wiring and it will work. Now, I have sysex, is there a place on forums that walks me through the steps of what to actually do with sysex?

[John]

Yes.

http://forum.highlyliquid.com/showthread.php?t=280

Be sure to let me know if you have questions.

[Joe.fisher]

Can this same circuit be used for two manuals, say Great and Solo and no 2nd touch?

[John]

Originally Posted by Joe.fisher

Can this same circuit be used for two manuals, say Great and Solo and no 2nd touch?

Hi Joe,

Yes, this approach will work equally well for two separate manuals.

[Joe.fisher]

Being new this this type of configuration, the questions is instead of a manual with 2nd touch, can this be use for two manuals, say Great and Solo?