360 Systems TCR Multi-Track - Manual (Page 63)

TCR Series UserManual Operations 4-13
Pre-roll and post-roll duration
The pre-roll or post-roll duration can be configured in the PREFERENCES section of the MACHINE
SETUP menu. The range of values can be from zero to 10 seconds.
Performing the Review
To review a punch-in recording or an auto record, press REVIEW once the transport has stopped. To
review an arbitrary file section, first set the Edit-In and Edit-Out points and then press REVIEW. The
selected audio plays at 1X unless varispeed playback is enabled for some other speed.
Variable-Speed Playback
Playback speed can be adjusted from 0.1X to 2X in 0.1 percent increments for non-time code
applications. The audio pitch correlates to the selected speed. This stretches or compresses the time
line making time code synchronization inaccurate. However, variable speed playback can be
triggered by time code using the CHASE UNTIL LOCKED, THEN FREERUN option.
Initiating Off-Speed Playback
Press the VARI button to enable variable speed playback then press PLAY or REVIEW to initiate
playback. Press VARI again to switch between variable speed playback and 1X playback.
Adjusting the Playback Speed
Press ADJUST while the VARI button is illuminated to adjust the playback speed. During VARI
ADJUST the function of the wheel changes from jog/shuttle to speed adjustment. The VARI speed
value is displayed in the lower right hand corner of the TRANSPORT SCREEN. The speed can be
adjusted during playback. Press ADJUST again to confirm the adjustment and restore normal
jog/shuttle function to the wheel.
Digital Output Dithering
MENU | Machine Setup | Audio I/O | Output Word Size
The TCR always records audio using a digital word size of 24 bits. However, it is sometimes
desirable to play out using a smaller digital output word size for use by external equipment, such as a
16-bit DAT recorder. If the output material is anything but white noise, its sample stream will be
correlated. This is particularly true of music. The effect of simply truncating the 24 bit samples to 16
bits results in the quantization error being correlated to the signal, producing signal distortion.
Dithering is a technique of adding an appropriate random noise source to the 24-bit digital output
stream before reducing the word size. This effectively decorrelates the quantization error from the
signal, resulting in a very low-level broadband hiss being added to the signal, rather than the more
objectionable signal distortion.
The TCR uses a zero-mean random noise source with a triangular probability distribution. Its peak
level corresponds to the magnitude of the least significant bit of the reduced word size within the 24-
bit field. The method is called “LSB TPDF dither” for Least Significant Bit Triangular Probability
Density Function.
The OUTPUT WORD SIZE selection in the Machine Setup | Audio I/O menu gives you three
choices: 24 BITS (no dithering), 20 BITS (4 bit dithering), or 16 BITS (8 bit dithering.)