CAKEWALK sonar x3, Справочное руководство

Страница: 297 / 2094

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Input monitoring
Recording
The bottom block of the picture represents the sound card. The shaded area above it represents the
audio drivers. The unshaded area at the top represents the main environment of the operating
system.
As the diagram shows, analog audio flows into the card's line input (on the left), and is immediately
split in two. One branch goes up through the analog-to-digital converter (ADC), where the audio is
digitized, buffered and fed to the driver (labeled Wave In in the diagram).
The digital audio data buffers are read by SONAR from the Wave In driver, processed, and then sent
out to the Wave Out driver. The driver passes the digital audio buffers through a digital-to-analog
converter (DAC), where the audio data is converted back to an analog signal.
Finally, this analog output signal is mixed with the original branch of the input analog signal, and the
summed result is presented to the sound card's line output.
With this information in hand, let's follow a simple audio signal through the system to understand
how echoes get introduced into the input monitor path.
Suppose you are counting “1, 2, 3" into your sound card very quickly. When you say the first “1,” this
sound immediately appears in all the places indicated in the illustration above. In other words, the
analog audio signal is pure electrical signal traveling at the speed of light, so it is immediately
present across all analog audio paths inside the sound card.
say “1”
SONAR