182
traveling at the speed of light, so it is immediately present across all analog audio
paths inside the sound card.
Next, you say "2." In the time it takes you do that, the ADC has converted the "1"
to digital form and the Wave In driver has fed it to SONAR for processing. SONAR
processes the buffer right away and passes the processed data right back to the
Wave Out driver.
Finally, you say "3." By this time the original "1" has been converted back to analog
audio by the DAC, and that analog signal is mixed in with the "3" you have just
said. The ultimate result is that you hear a "1" and "3" mixed together at the line
output of card—seemingly sounding like an echo, but actually just an artifact of
the signal flow through the system.
You can eliminate the echo by muting the line-in from playing back (see “To
Eliminate the Echo from Input Monitoring” on page 183); you’ll send only the
processed signal to the sound card outputs. This technique introduces a little extra
latency to what you hear coming out of your sound card, but if you use WDM or
ASIO drivers with your sound cards, the latency is negligible.
The feedback problem results whenever you have a loop in your mixer path: the
output of your mixer is patched into the input of your sound card. Feedback can
say “2”
say “3”
To Next Page
Loading...