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MIDI-CEP

How to control Audition / Cool Edit with MIDI events

During recording session either in studio or in the field there is a need to communicate with the performes. See Fig.1. It is usually done by voice using the mic from the place of the console and also by red light visible by performers which denotes recording is in progress. For such purpose I have adjusted the red light directy on the top of communicating monitor, Fig.2. I toggled the red light switch manually and, of course, often forget untimely either it is off or on.

The elegant solution would be the possibility to toggle the red light automatically from recording program (Audition/CEP) synchronous with Record/Pause function.

During some discussion on Audition/CEP forum I was directed to the reversed possibility to control CEP from outer world with MIDI notes or commands (events) leaded to the MIDI input port on the sound card. CEP has namely the ability to control the majority of its functions not only by keyboard shortcuts, but at the same time by the MIDI events. To use this possibility it remains to build some additional hardware which sends MIDI event which is then in CEP associated with the Record/Pause function and at the same time this outer hardware toggles the red light ON/OFF.

The first step I had to undertaken was to made myself somewhat familiar with MIDI. Some basic information you could find in next links or use Google.

http://multiple.insertions.com/mi_html/contrib/other/bobw/midi.htm
http://www.harmony-central.com/MIDI/Doc/tutorial.html

The one who wishes to be overhelmed with information is recomended to input in Google search machine words: "MIDI Tutorial".

The next step, before building any hardware, was to prove, how it works in reality.

For the third and last step you either must possess the ability to understand the design and realization of microcontroller hardware or, as I, have the close friend who possess all this capabilities.

Realization. First of all I have drawn a block scheme, how I imagine the required hardware should work. See Fig.3. My requirement was that in the generator box must be also a "Unmute button" which enables to speak to performers and that the audio communication and DC current for the red light must be conducted in single cable to somewhat reduce the layed cable "salad" (no multicable used).

My friend decided to build the MIDI generator on his favorite ATMEL microcontroller AT89C2051 (2.7 Volt, 2 kB flash memory, 20-Pin Package, compatible with the industry standard MCS instruction set.) instead on commonly used PIC controllers. Although for the required function only one MIDI code is required, we decided for the future experiments with various CEP functions to build ten MIDI code generator. The particular codes are to be selected with the rotary ten-pole BCD switch.

Resulting groundwork for inspiration is here: schematics for the MIDI generator. (The BCD switch is not correctly drawed, I have not found in Eagle┤s library the correct one. Sorry for that .) The same schematics in EAGLE format, program for microcontroller in source code and in hex format. Realized box of MIDI generator is on Fig.4 all assembled equipment for communication on Fig.5.

Using the MIDI generator with CEP is described in the next section How it works. I have tested all the communicating equipment during the real recording session and it really simplifies the work. The generator box with its two keys is located besides the left side of the PC-keyboard and is handled by the left hand as well as all keyboard shortcuts I use. The right hand does not leave the mouse.

How it works

To prove controlling CEP with MIDI commands before building any microcontroller hardware generator you need either MIDI keyboard or, if you do not have any as I, you could use the second computer as the MIDI generator.

First examine, if your sound cards in both computers have MIDI DIN connectors. My M-Audio Delta-1010 has MIDI IN and OUT connectors and on second computer SB Live sound card has cable adapters for it. If any of your computers has only MIDI on joystick connector, then some hardware work with soldering iron is unavoidable.

For getting MIDI in work is valuable simple MIDI detector tool. Any activity on MIDI OUT is seen as weak LED flicker.

Then you need some software running on second computer which generates MIDI codes. The simpliest way is to use freeware MOUSE KEYBOARD or much better (and also more sophisticated) freeware MIDIOX. Either software must be properly configured. MOUSE KEYBOARD in MIDI Out, MIDIOX in Options / MIDI Devices. What MIDI device to select depends on your particular sound card and computer configuration. If you are not sure, then use the method of "trial and error" or better, "trial and success". For such experimenting mentioned MIDI detector tool is invaluable. Use the communication on Channel 1 for simplicity. Always verify with the MIDI detector connected to the MIDI OUT that any generated event (note or control code) is accompanied with LED flicker.

Connect both computers with MIDI cable. It must be connected on computer which serve as MIDI generator to MIDI OUT connector, on computer where CEP is running in MIDI IN connector of course.

Start Cool Edit 2.1 (or Audition) on first computer, configured MOUSE KEYBOARD or MIDIOX on second computer.

  1. In CEP create new waveform: "File / New / OK".
  2. Press F6. In bottom left corner "Opened MIDI Input Sync/Trigger" appears. F6 is toggle function which opens/stops MIDI trigger capability. Leave it open.
  3. Go to "Options / Shortcuts (Keyboard&MIDI Triggers.." and select "Category / Transport / Record/Pause toggle".
  4. Move cursor to the window MIDI Trigger. Verify that Channel is 1. (If you use the communication on channel 1 on second computer of course.)
  5. On the second computer generate MIDI event, say note "C3 ON" (Hex codes: 90 30 7F).
  6. On the first computer in MIDI Trigger window appears: "Note C3 (48)"
  7. Close Shortcuts window clicking on OK.
  8. From this point on, anytime you send to the first computer MIDI note C3 from the second computer (or any other hardware) CEP starts recording. Next C3 note pauses the recording etc. If you wish to end recording you must press in CEP the STOP button.
  9. If you use the real add-on hardware for Record/Pause and red light triggering as I described in previous section and you lost sync between recording and red light lit, simply stop MIDI triggering in CEP by pressing F6, correct the situation and press F6 again.

Does it work as described? If not, then load MIDIOX also in the first computer, configure it for following MIDI events on IN port. Now send MIDI events from second computer and see if they arrived to the first computer, use also MIDI test tool and think, test, think...

If you use CEP 1.2 the sequence for setting MIDI triggering is somewhat different as described, but you surely find your way, don┤t you?