Reference Guide

1313
Improving performance with digital audio
Improving audio performance
follow any special card-specific operating instructions listed there.
• Re-test audio recording/playback. If problem(s) persist, go to the Next Step.
The “I/O Buffer Size” may not be well matched to your hard disk
SONAR may be reading and writing audio data to/from your hard disk in chunks that are either too
large or too small for your particular hard disk's characteristics.
Go to Edit > Preferences > Audio - Sync and Caching and try different values for Playback I/O
Buffer Size and Record I/O Buffer Size until you find values that works well for your particular hard
disk:
• The default value is 64. Try reducing this value, to 32, then 16. After each change, close the
dialog box (click OK) and re-test your project's recording/playback behavior.
• If problem(s) persist, try increasing this value, to 128, then 256, then 512. Again, close the dialog
box and re-try your project after each change.
• If you have an older, slower computer or an older, slower hard disk, you should try increasing the
buffer size; decreasing is not advised on slower hardware. However, increasing this setting uses
more of your computer's RAM. If you have a smaller amount of RAM in your computer, increasing
the buffer size may not help.
If problem(s) persist, restore this value to its default and continue with the next step.
Mixing latency may be set too low
SONAR tries to send and receive audio data to/from your sound card with very a minimal delay (so
that any real-time adjustments you make to a track's volume, pan, or other settings will take effect
rapidly). If the latency setting is set too low, the sound card driver may not be able to keep up with
the SONAR, and audio will be disrupted.
Try higher latency settings:
•Go to Edit > Preferences > Audio - Driver Settings . Move the Mixing Latency Buffer Size
slider control to the right in small increments until you see the value to the right of the slider
increase; close the dialog box (click OK) and re-test your project after each increment.
• If problem(s) continue, move the slider control back to its original position, and try increasing the
number in the Buffers in Playback Queue text box. (This value starts out at 4; try increasing it to
5, 6, 7, or 8). Close the dialog box (click OK) and re-test your project after each such change.
• The total effective latency is displayed below the slider; it is determined by multiplying the per-
buffer latency time (in msec) by the number of buffers in the playback queue.
Your hard disk may be excessively fragmented
Audio data can be processed most efficiently if it is arranged in consecutive physical locations on
your hard drive. Over time, the chunks become distributed at various discontiguous locations on
your disk, which makes it more time consuming for SONAR to access the chunks. This extra access
time can interfere with smooth audio recording and/or playback.
Try defragmenting the hard disk:
• Make sure SONAR, and the Wave data directory are not installed on a compressed hard disk.