Instruction Manual

837
SMPTE/MIDI Time Code Synchronization
Synchronizing Your Gear
2. Check the desired option from the Synchronization list.
3. Click OK.
Audio playback under time code sync is handled according to the setting
you chose.
SMPTE/MTC Sync and Full Chase Lock
When using SMPTE/MTC Sync with full chase lock, the first time you play
any audio the pitch may fluctuate wildly for up to 30 seconds. Also, you may
occasionally note the pitch of the audio sounding consistently high or low
pitch.
A simple analogy makes this behavior easy to understand: Synchronizing
audio to SMPTE/MTC is a lot like trying to get even and stay neck-and-neck
with another car on the freeway. If the car is ahead of you, you need to drive
faster to catch up to it. If it's behind you, you have to slow until the car
catches up to you. Once the two cars are neck-and-neck, you can simply
keep going at the same speed, unless the other car changes its speed. If
the other car speeds or slows, you must speed or slow too.
The first time you play audio under SMPTE/MTC Sync, the audio clock has
to get even with the external clock. This could mean racing ahead, which
raises the pitch of the audio, or stepping on the brakes, which lowers the
pitch of the audio. These fluctuations continue until SONAR matches its
playback speed to the external clock, which usually takes no more than 30
seconds. The stable playback speed, by the way, may be slightly faster or
slower than the normal audio playback speed, resulting in a slight change in
the pitch of the audio. Here’s the best way to address this problem:
• Start each new SONAR session by playing some audio under SMPTE/
MTC Sync.
• Let the audio play for 30 seconds or until all audio pitch fluctuations
stop.
Once this procedure is complete, SONAR knows the difference in rates
between the external time code and the audio clock on your sound card.
For the rest of the session, SONAR will start playback closely in sync,
without any drastic pitch changes.
If the external timing source were 100 percent stable, the audio would stay
in sync with the external clock. Unfortunately, no timing source is perfect.
Therefore, every once in a while after playback has started, SONAR may
need to vary the playback speed by a tiny amount to stay even with the time
code. If the time code signal is unstable (as might be the case from an