Specifications
Pro Tools Reference Guide430
Sending MIDI Beat Clock Over
IAC
(Mac Only)
You can synchronize other MIDI applications that
use the Apple Inter-Application Communication
(IAC) driver to Pro Tools by transmitting MIDI
Beat Clock on the IAC bus.
To transmit MIDI Beat Clock on the IAC bus:
1 Choose Setup > MIDI > MIDI Studio.
2 In the MIDI Devices window of Audio MIDI
Setup, double-click the IAC Driver icon.
3 Configure the IAC Driver ports and confirm
that it is online.
4 Choose Setup > MIDI > MIDI Beat Clock.
5 In the MIDI Beat Clock dialog, select the
Enable MIDI Beat Clock option.
6 Select the IAC Driver ports you want to enable
for sending MIDI Beat Clock.
7 Click OK.
MIDI Beat Clock Offsets
You can set an offset for MIDI Beat Clock on a
port-by-port basis with your MIDI interface and
external MIDI devices. This lets you adjust the
timing for each device where some devices sound
late due to different, fixed latencies. Where appro-
priate, enter negative offset values in samples for
each port to correctly synchronize the audio sig-
nals from your external MIDI devices with
Pro Tools playback.
Measuring Beat Clock Latency
To determine the correct MIDI Beat Clock offset for
an external MIDI device:
1 Ensure that your computer and external MIDI
device are correctly connected and configured
for MIDI, and that its audio output is correctly
connected to audio inputs on your Pro Tools au-
dio interface.
2 Ensure that your external MIDI device is con-
figured to receive MIDI Beat Clock, and that it
is correctly configured to play back a simple
rhythmic pattern “on the beat.”
3 Create a new Pro Tools session.
4 In the MIDI Beat Clock dialog, ensure that MIDI
Beat Clock
is enabled and that the device is se-
lected.
5 Set the Main Time Scale to Bars|Beats.
6 Create a new audio track and select the audio in-
put channels for your external MIDI device.
7 Record enable the audio track and start record-
ing. MIDI Beat Clock is sent to the external
MIDI device, which starts playing back the
pattern.
8 Stop recording after a few bars.
9 Enable both Snap to Grid and Show Grid.