360 Systems TCR Multi-Track - Manual (Page 57)

TCR Series UserManual Operations 4-7
Suppose, for example, that you wanted to copy track 1 to track 4. One way of doing this would be to
connect a cable from digital outputs 1-2 to digital inputs 3-4, arm track 4 only, and press Record. The
resulting audio on track 4 would be in phase with track 1 when it was played back.
If, however, you were to route the track 1 digital output through an external device, such as an effects
processor or digital mixer, then the processing delays in the external equipment would cause the
playback of track 4 to lag behind the audio on track 1. The TCR can compensate for these external
delays during the recording process so that the delayed signal recorded on track 4 plays back in phase
with track 1.
The amount of delay incurred by the external equipment is specified in sample times for the track
being recorded using the Set External Process Delays menu.
You can establish the appropriate process delay value by trial and error, making trial recordings with
different process delay values until the source track and newly recorded track play back in phase.
Alternatively, you can measure the process delay and compute the delay value for the track to be
recorded.
To measure the process delay, record a test signal such as periodic clicks on to a reference track, say
track 1. Then route the output of this reference track through the external equipment to the input of,
say, track 4. Set the process delay for track 4 to be zero, arm track 4 only, and record on track 4 for
several seconds (while track 1 is playing). Now, playback the recording and measure the phase
difference between the analog outputs of tracks 1 and 4 using a dual trace oscilloscope. Divide this
time measurement by the sample period (20.833 microseconds, when the sample rate is 48000Hz) to
obtain the number of samples to be used in the process delay menu.
For example, suppose you observed during playback that the clicks on track 4 lag behind the clicks on
track 1 by 800
µ
sec. The value to be entered for the Process Delay for Tracks 3-4 would be computed
to be (800
µ
sec / 20.833
µ
sec per sample) = 38 samples. The next time a recording is made using this
process delay, you will see that upon playback, tracks 1 and 4 will be in phase.
RMW Selection
The R-M-W button toggles the Read-Modify-Write mode on and off. When R-M-W is enabled,
playback audio is available at channel outputs directly off of disk (without going through the
channel’s crossfader). This allows you to route a channel’s output through external processing
equipment and back to the same channel’s input for re-recording, without the associated delay and
feed back problems. When R-M-W is off, the audio being recorded may be heard on the track
outputs.
For example, you may want to add some echo effects to certain parts of a voice recording on track 1.
You can route the analog or digital output of track 1 to an effects generator, and send the output of the
effects box to the analog or digital input of track 1. When you punch-in on track 1, the original voice
material will be replaced by the echoed voice. Note that if there are any delays associated with the
external effects generator, then the appropriate process delay should be applied to track 1 as discussed
above.