NOTE: This project is has been discontinued, and is provided only for historical reference. Please see multichannel audio player 2 instead.

• Design Overview
• Block Diagram
• Fallback Plans (Modes of Operation)

• Related Pages

The left channel is fed into low-pass and high-pass filters.

• The output of the high-pass filter is the 3 kHz carrier modulated by the volume envelope. It is our recovered "animation audio" channel.
• The output of the low-pass filter contains the DTMF tones of our control channel.

The control channel is fed into a DTMF decoder that converts tones into a four-bit binary value validated by a strobe signal. The strobe latches the binary value into a quad latch, which drives relays to select which performer(s) get the sound track.

Block Diagram

This block diagram shows the major components of the multichannel player:

• Plan A - Create the perfect CD
  • RIGHT: speaker audio
  • LEFT: mixed DTMF and custom volume envelope (of just the vocal part of audio)

  • Pros: You can control who sings and talks. Jaw motion reflects only the vocals. (No problems when you hit the bass drum during vocals. Mouth doesn't move along with passages between vocals.)
  • Cons: It takes some time, effort, and expertise to create the CD.
  This will be worth it.

• Plan B CD
  • RIGHT: speaker audio
  • LEFT: mixed DTMF and volume envelope (of mono right track, with non-vocals cut out)

  • Pros: You can control who sings and talks. Mouth doesn't move along with passages between vocals.
  • Cons: The mouths move when you hit the bass drum during vocals.

• Plan C CD
  • RIGHT: original source material mixed-down to mono
  • LEFT: only DTMF

  • Pros: You can control who sings and talks. Mouth doesn't move along with passages between vocals.
  • Cons: The mouths move when you hit the bass drum during vocals.

• Plan D CD
  • RIGHT: original source material mixed-down to mono
  • LEFT: the only thing is your voice, dubbed in for talking or singing
  • [switch off the DTMF decoder]

  • Pros: This is easy to do. Mouth doesn't move along with passages between vocals. No problems when you hit the bass drum during vocals.
  • Cons: All the props say/sing the same thing.

• Plan E CD
  • RIGHT: original source material mixed-down to mono
  • LEFT: same, except deleting sound where nobody is talking or singing
  • [switch off the DTMF decoder]

  • Pros: This is very easy to do. Mouth doesn't move along with passages between vocals.
  • Cons: All the props say/sing the same thing. The mouths move when you hit the bass drum during vocals.

• Plan F - If all else fails, use any CD
  • use a standard stereo CD
  • [switch off the DTMF decoder]

  • Pros: There will be something on the right that sounds good enough, and something on the left that will look good enough.
  • Cons: All the props say/sing the same thing. The mouths move when you hit the bass drum during vocals. The mouths move during the background music, even when nobody should be singing.

Where the drawbacks are:

• same - All performers sing in unison.
• tween - Sounds that happen before, between, and after vocals cause mouths to move.
• during - Sounds that happen at same time as vocals cause mouths to move.

We have some configuration switches that provide maximum flexibility and allow for the fallback plans.

Please note that the many choices of fallback techniques are provided in case it is too expensive, time-consuming, or difficult to do it the best way. Selecting one of the less desirable approaches still requires basically the same equipment. It just saves effort in the making of the program material.

• multichannel audio player 1
• overall design [this page]
• tone control design
• schematic diagrams
• making the recording

Thank you for visiting. Your comments are welcome.
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