Apple Logic Express 8 - Manual (Page 854)

854 Chapter 35 Synchronizing Logic Express
Audio Sync Mode
This is where you define how your audio hardware should be synchronized to an
external time code master.
Not all audio hardware can work in every sync mode described below. This is
particularly dependent on whether or not the hardware’s sample rate can be
controlled.
You can choose the following options in the Core Audio menu:
 MTC Continuous (default): Audio regions are started in sync, and the sample rate is
continuously regulated to match variations in the time code master signal. Even very
long audio regions stay in sync in this mode.
 MTC Trigger + Auto Speed Detection: Similar to MTC Trigger (see below), but the
tempo of the time code master is constantly monitored while Logic Express is
running. The next time you start Logic Express, it will use an adapted sample rate.
This mode keeps long regions in better sync with the time code master, although not
as closely as MTC Continuous. It does, however, use a constant sample rate, which is
not affected by variations in the time code master signal.
 MTC Trigger: Audio regions are started in sync, but are then played at a constant
sample rate, regardless of any variations in the time code master signal. Logic Express
always uses the set nominal sample rate (44.1, 48, 88.2, 96, 192 kHz). This mode is
suitable when it is vital to retain the absolute pitch of a recording. If the speed of the
time code master deviates from the nominal value, you may need to split long audio
regions into shorter sections.
 External or Free: Logic Express has no influence on the sample rate. The audio
hardware is responsible for ensuring that the position and sample rate of audio
regions match. This mode is only advisable if you are sure that the Word Clock and
time code master are running in sync—by using an external SMPTE or Word Clock
synchronizer, for example.