MIDI to Expression Pedal

I have a number of sample sets working very nicely on my Rodgers C440. But, I have yet to figure out how to connect the expression pedal from say the Moseley to my physical pedal. I can work it with the mouse, but that isn't what I need. The MIDI tabs on the Rodgers only list Swell, Great and Pedal. Further, it is only a stereo input. Will it not work? Many thanks.
Sandy Hackney
Easton, NY

[mdyde]

Hello Sandy,

What MIDI messages (if any) does your Rodgers' expression pedal send?

This tutorial explains how to use Hauptwerk's MIDI logging facility to find out (it refers to configuring stop switches, but the process is analogous for continuous controls, i.e. expression pedals):

http://www.hauptwerk.com/clientuploads/documentation/Tutorials/MIDI-Logging-Tutorial.pdf

A different approach - rather than repeat what I did with my Rodgers 340, you can check it out here (on the 2nd page) http://site.virtualorgan.com/community/viewtopic.php?f=40&t=694 Zero problems to date.

Rgds,
Ed

Thank you Martin and Ed! Martin, I'll follow up with the link. Ed, What an Impressive Job! I am humbled... I was proud of getting HW to work with my Rodgers, but you have shown me a new dimension. Many, many thanks!!

Hello Sandy,

What MIDI messages (if any) does your Rodgers' expression pedal send?

This tutorial explains how to use Hauptwerk's MIDI logging facility to find out (it refers to configuring stop switches, but the process is analogous for continuous controls, i.e. expression pedals):

http://www.hauptwerk.com/clientuploads/documentation/Tutorials/MIDI-Logging-Tutorial.pdf

Hi Martin,

I've tried to follow up the procedure without success so far.

I have a M-Audio EXP Universal Expression Controller Pedal attached to a M-Audio Keystation 61es connected to a M-Audio MidiSport 4X4 Anniversary Edition.

When pressing up on the pedal, the LED corresponding to the Midisport 1st port used for the Keystation 61es is flashing, showing an incoming message is going through. When I press down, same LED reaction.

The Midi logging procedure was successful. I reported all data in Hauptwerk, as mentionned in your tutorial, but nothing happened... Did I miss anything?

By the way, is it normal the MidiSport LED is only flashing once when pressing the pedal (from minimum to maximum and vice versa)?

Is it simply the (basic) equipment I am using which is incompatible with this procedure?

Thanks in advance for your help!

[mdyde]

Hello Pat,

The Midi logging procedure was successful. I reported all data in Hauptwerk, as mentionned in your tutorial, but nothing happened... Did I miss anything?

Can you clarify?

The purpose of the MIDI logging exercise is to log the MIDI messages that your pedal is sending in the activity log ('Help | View error/activity log' and scroll to the end after moving your pedal with MIDI logging on).

What entries were/are written to the log as you moved/move the pedal?

When pressing up on the pedal, the LED corresponding to the Midisport 1st port used for the Keystation 61es is flashing, showing an incoming message is going through. When I press down, same LED reaction.

That's fine - that means that the pedal is sending MIDI.

By the way, is it normal the MidiSport LED is only flashing once when pressing the pedal (from minimum to maximum and vice versa)?

Yes - it should flash on and stay lit as long as the pedal is actually moving.

Can you clarify?

Sorry I was not articulate... I meant I couldn't get the pedal be recognised in Hauptzwerk...

What entries were/are written to the log as you moved/move the pedal?

Here you are -

2010-02-28-20-36-27: INF:2553 Diag: IN: MIDI control change: port: MIDISPORT 4x4 Anniv IN1, channel (1-16): 01, controller (0-127): 064, value (0-127): 127. [ACT:2411 MIDI diagnostics]

2010-02-28-20-36-28: INF:2553 Diag: IN: MIDI control change: port: MIDISPORT 4x4 Anniv IN1, channel (1-16): 01, controller (0-127): 064, value (0-127): 000. [ACT:2411 MIDI diagnostics]

That's fine - that means that the pedal is sending MIDI.

Absolutely, this is what I deducted!

Yes - it should flash on and stay lit as long as the pedal is actually moving.

And this is where another problem comes - it's lit for one second or less, ie less time I'm pressing on the pedal on its way from minimum to maximum or vice versa...

[B. Milan]

Hello Pat,

The MIDI logging information shows that your expression pedal sends on MIDI channel 1 with a controller value of 64. Thus you need to set these in the General settings | Continuous controller MIDI inputs as follows:

Click each image for a larger view...

(This example uses the setting for the item named Swell using St. Anne's)

Then once that is done go to Organ settings | Connect continuous control MIDI inputs to organ continuous controls... and map the virtual Swell pedal to the proper input (Swell):

Then once done your pedal should control the virtual expression pedal.

And this is where another problem comes - it's lit for one second or less, ie less time I'm pressing on the pedal on its way from minimum to maximum or vice versa.

As long as it is sending the full range of continuous control values I wouldn't worry about whether or not the LED stays lit continuously. Perhaps the MIDI interface just cannot keep up with the series of incoming MIDI messages to trigger the LED. If you set everything as above and the virtual expression works then the LED shouldn't matter.

Hi Sandy,

I noticed you were using the SUSTAIN input on the 61es which is configured for a pedal-switch and not a potentiometer, such as in the expression pedal you have. Because of this, the 61es may only be sending the values 0 and 64 and not a continuous set from 0 to 127 as you would need. (that would explain the strange light behaviour.) Perhaps you want to investigate a continuous MIDI encoder (I believe MIDI boutique sells one) to get a controller which produces a continuous controller value like Volume (7) or expression (11) over the full range of values.

Also, it seems like using the 61es just for the MIDI encoder for the pedal might be a bit of an overkill. However if you are using the 61es as an additional manual, perhaps you can rewire the volume slider on the 61es to a jack (available at radio shack) for the expression pedal. I am doing this in another conversion-in-process and it works well.

Hope this helps a bit.

Pax,

Thomas

Hello Pat,

The MIDI logging information shows that your expression pedal sends on MIDI channel 1 with a controller value of 64. Thus you need to set these in the General settings | Continuous controller MIDI inputs as follows:

Click each image for a larger view...

(This example uses the setting for the item named Swell using St. Anne's)

cc-inputs.jpg

Then once that is done go to Organ settings | Connect continuous control MIDI inputs to organ continuous controls... and map the virtual Swell pedal to the proper input (Swell):

cc-inputs-2.jpg

Then once done your pedal should control the virtual expression pedal.

And this is where another problem comes - it's lit for one second or less, ie less time I'm pressing on the pedal on its way from minimum to maximum or vice versa.

As long as it is sending the full range of continuous control values I wouldn't worry about whether or not the LED stays lit continuously. Perhaps the MIDI interface just cannot keep up with the series of incoming MIDI messages to trigger the LED. If you set everything as above and the virtual expression works then the LED shouldn't matter.

Thanks for the detailed info, Brett!

I tried this morning with no luck... but it was before I got my daily caffeine minimal dose to be really efficient. I shall give another try when I am back home tomorrow night...

As for the LED lighting up or not, I think you are right - when I press a key, no matter how long it is, the LED is lit when I press it, and when I release it, but remains off inbetween.

Hi Sandy,

Hi Thomas, I think you are referring to me as Sandy is using a Rodgers C440.

I noticed you were using the SUSTAIN input on the 61es which is configured for a pedal-switch and not a potentiometer, such as in the expression pedal you have. Because of this, the 61es may only be sending the values 0 and 64 and not a continuous set from 0 to 127 as you would need. (that would explain the strange light behaviour.) Perhaps you want to investigate a continuous MIDI encoder (I believe MIDI boutique sells one) to get a controller which produces a continuous controller value like Volume (7) or expression (11) over the full range of values.

Thanks for the explanation Thomas...

I had requested an expression pedal when purchasing it - together with the 61es - and insisted I didn't want the sustain pedal they were proposing me at first. It looks from what you write that I didn't get the right product in the end...

Also, it seems like using the 61es just for the MIDI encoder for the pedal might be a bit of an overkill. However if you are using the 61es as an additional manual, perhaps you can rewire the volume slider on the 61es to a jack (available at radio shack) for the expression pedal. I am doing this in another conversion-in-process and it works well.

Radio Shack has disappeared recently in the UAE, but anyway it has never been comparable to the real ones you have in the States – basically it was an electronic shop selling devices and very few components.

My 61es-based setup is a temporary solution, before I can afford to move to a more serious one. I bought this basic pedal as I thought it allowed me to be closer to a real organ, but if not the case, it shall not be a big deal. For the time being, I’m more practising than anything else – I have not played the organs for a few decades!

If my further trial is not more successful, I shall disconnect it and place it back to the cupboard without hard feeling…

Thanks for detailing all this info, I do appreciate Thomas!

Slightly off topic, but it could be of general interest. I posted this a while ago on the MidiTzer forum:
A very inexpensive and simple solution is the MRG3 board from http://www.midi-hardware.com/ I discussed the issue of MIDI flooding from expression controls with Roman Sowa, the owner and designer.

Roman is the first one to describe the operation of his pedal controller that should work with almost any MIDI VPO system. He has done this by only sampling the analog output at a rate slower than the 1000 messages per second used by the traditional MIDI interface. I have been saying this for years. If the manufacture of the swell shoe controller won’t specify how fast they can output messages, I wouldn’t buy it. Faster doesn’t mean that it is better in this case. Faster only means that you will be flooding the MIDI port with unnecessary swell shoe messages. Most people would look at a specification and naturally say “faster is better” so they buy the faster better unit not knowing the difference. Now a marketer would have to say “with special feature that won’t affect the keyboard latency” without saying that this feature is done by slowing things down.

Rgds,
Ed

Yours is a timely post, Ed, as I've spent part of last night and this morning adding potentiometer scanning to my encoder project. Even with a scan rate somewhere in the neighborhood of every 5 ms there is still a need for some smoothing, such as averaging with the previous readings, in order to get well behaved swell pedals in the real world. If I've learned nothing else, it's that most of the midi designers are doing us a real service in paying attention to these details. If I remember correctly, the MidiBoutique unit that I've been using scans the keys 1000 times per second and the pots 200 times per second.

At the moment I'm using 5 scans to debounce both make and break on the keys, though I've heard of some older keyboards needing a longer time. Anyway, when my programming bugs rear there ugly heads I find out fast how well my interrupt scheme is working!! It's certainly no challenge to overrun a MIDI transmit buffer.

This all started with that thread about turning power amps on after receiving the HW "organ loaded" message. All in order to avoid the big thump that we've all heard a time or two. So one thing led to another, and now the part about controlling the amp is so simple that I haven't gotten around to trying it yet.

Even with a scan rate somewhere in the neighborhood of every 5 ms there is still a need for some smoothing, such as averaging with the previous readings, in order to get well behaved swell pedals

Agreed. I scan mine every 8 ms but average the current reading with the previous seven. And then I add some hysteresis to that, so the result is very smooth.

Sorry Pat,

I didn't mean to hijack the thread. Yes I thought I was talking to Sandy.

But DO look into using the volume slider or the modulation wheel by soldering your 3 wires from the pedal to either the slider pot on volume or the wheel pot on the modulation. I believe it will be worth the effort.
Pax,
Thomas