Clicks And Pops - Tascam PCI-822 User Manual

• Clicks and pops

Audio artifacts, also known as clicks and pops, can be caused by a
variety of conditions. Here are some suggestions for eliminating clicks
and pops.
— Synchronization —
The most common cause of glitches in the audio is an incorrect clock
source setting. For digital audio recording or playback, it's important
to remember that there must be one and only one audio clock master
in your digital audio system.
For example, if you're using an external multichannel A/D converter
which is running on its internal clock, then the converter is the audio
clock master, and the soundcard must be locked to that master by
setting the card's Clock Source to the appropriate setting. If the A/D
converter is connected to the card via the TDIF connector, set the
Clock Source to "TDIF" in the PCI-822 control panel. If the A/D
converter is transmitting audio to the RCA (coax) connector, set the
PCI-822 Clock Source to "SPDIF" in the control panel.
If both the external A/D converter and the digital soundcard are set to
Internal (both are trying to be clock masters), then the recording will
contain clicks at regular intervals. Tick ... tick ... tick. The rate of these
clicks is determined by how closely matched the internal clocks of the
external converter and the soundcard are. When this problem occurs,
the SLIP indicator for that input (in the PCI-822 control panel) flashes
red at regular intervals. Similar synchronization errors can also occur
on playback.
For more information about synchronizing digital audio components,
please refer to "Using the PCI-822" earlier in this Guide.
30 PCI-822 User's Guide