Singing with Votrax SC-01


As of 1 Jan 2014 the firmware of the controlling Arduino board has been completed and it is now possible to make the Votrax sing with correct lyrics !

Unfortunately the procedure to make the Votrax sing is not exactly straightforward, so for the time being it won't be available on-line.

However, if you are interested in producing your own song, follow the procedure below to create a MIDI file in the proper format, and send it to me. Then I will generate the audio file off-line and send it back to you.

The procedure is as follows:

  1. Start off with a MIDI file with only notes on MIDI channel 5.
    Make sure you never have more than one note playing at any single time.
    Make sure you only use notes in the range A0 to C#4 (MIDI note number 21 to 61).
  2. Place a program change event at the beginning of the song to select program 2.
    (The firmware allows using the Votrax also for live performance, for example connected to a keyboard, but program 2 is the one used for this "karaoke" mode)
  3. The concept is that we can define a string of phonemes that get triggered at the MIDI note on event, and a separate string of phonemes for the MIDI note off event.
    We use MIDI Control Change 80 and 81, respectively.
  4. You need to work out your string of phonemes for the whole song, and place each group of typically one or two or three phonemes before the corresponding note event.

    To make this task easier I have personally used the Windows utilities Midi2csv and Csv2Midi by John Walker

  5. For example, if you have a note G1 (MIDI note number 43) corresponding to the lyrics "your", and you want to break it down like this:
    sing "you-" at the note on event, so that the vowel sound can be sustained,
    sing "-r" at the note off event

    You have established by some other means that the word "your" can be synthesized by the Votrax phonemes Y O R (respectively 41 38 43)
    you would edit the csv file like this:

    	3, 14200, Control_c, 4, 80, 41
    	3, 14300, Control_c, 4, 80, 38
    	3, 14400, Note_on_c, 4, 43, 90
    	3, 15000, Control_c, 4, 81, 43
    	3, 15200, Note_on_c, 4, 43, 0

    The velocity of the "note on" event is completely disregarded, except of course if it is zero it means "note off".

  6. Modulation wheel is also supported to add vibrato to long notes, but please don't use it as yet, because you don't have an immediate feedback on what it would sound like.
    If it absolutely vital to your song, just describe it to me in the email that you will be sending me, and I'll add the vibrato myself.
  7. Run the Csv2Midi utility to re-create a MIDI file which you can send to me as an attachment to an email
  8. Please don't expect a speedy response from me, I'll do my best to render your audio file and place it in your user page on this site.
    There is no fee for this, but if it gets too time consuming in the future I might consider charging a minimal amount of money.

If you have any suggestion, please post a message in the Forum