Apple Soundtrack - Manual (Page 196)

196 Appendix C Solutions to Common Problems and Customer Support
 If you are using a USB audio interface, make sure the audio interface is directly
connected to your computer. Do not connect a USB audio interface through a USB
hub, or chain it through another USB device.
 If you experience unwanted noise or hiss, check the connections between your
computer and any external audio devices. Refer to the documentation that came
with each device for any additional instructions on dealing with noise.
Eliminating Recording Latency
You can use the Latency Compensation setting in the Preferences Recording pane to
eliminate any latency inherent in your recording device. You calculate the latency by
playing a loop and recording it at the same time, as described below:
1 Use an appropriate cable to connect the audio output port you are using to the input
port for the device from which you plan to record.
2 Choose a loop with a large number of transients, such as a drum loop.
3 Set the tempo to 60 bpm (to simplify the latency calculation).
4 Click the Record Enable button in the header of the track to which you want to record.
5 In the Recording tab, set the Input device to the recording device.
6 Set Monitor to None and ensure that hardware monitoring on your recording device is
turned off. You may also need to reduce input or output volumes of your devices in
order to avoid feedback.
7 Click the Record button and let the loop play for a few seconds. Then click Stop.
8 Visually compare the original track and the newly recorded track. Zoom in to identify a
place where the tracks have identical waveforms but are not lined up. Set the playhead
at the corresponding identical points on the two waveforms and subtract the two
Beats field values. This is the latency in milliseconds. If the recorded audio is late (to the
right), you enter a positive value; if it’s early (to the left), you enter a negative value. For
example, if the location in beats of the selected point in the source loop is 1.2.002 and
the location in beats of the corresponding point in the recording is 1.2.008, the latency
is 6 milliseconds.
9 Enter the latency value in the Recording Preferences pane.
10 Mute the recorded track and test record the loop again to make sure the latency
is eliminated.