Reference Guide

277
Input monitoring
Recording
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 278); 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 happen with or without input monitoring,
but since input monitoring can add several levels of gain to the signal flow, it’s of greater concern
when you have input monitoring enabled. Input monitoring is disabled by default when you install
SONAR, and you enable it with the following procedure.
To enable input monitoring
• Turn your speakers down, and on an audio track that you want to monitor, click the Input Echo
button so that it’s lit up (on) . To disable monitoring for this track, click the button off.
Or
• Turn your speakers down, then click the Input Echo On/Off All Tracks button in the Control
Bar’s Mix module. This enables input monitoring on all tracks. To disable monitoring for all tracks,
click the button again.
Now you can hear your instrument in real time with any plug-in effects that you want to patch into the
current track. You might also hear an echo, because the dry signal is coming out of your sound card
slightly ahead of the processed signal. To eliminate the dry signal, see the next procedure.
say “3”
SONAR