220 Chapter 18—Digital I/O
03D—Owner’s Manual
Output Dither
The 03D’s AES/EBU connection outputs digital audio data with a wordlength of 24 bits.
The Coaxial connection outputs digital audio data with a wordlength of 20 bits. When
a high-resolution digital audio signal is transferred to a lower-resolution system, some
of the least-significant bits (LSB) are ignored by the receiving system. This can make
low-level signals sound grainy and step like, similar to the breakup produced by a
low-resolution digital reverb processor as a signal fades. The wordlength of a digital
audio signal must be shortened to match that supported by the receiving system. The
digital dither technique is used to optimize this process. The output of a special pseu-
dorandom number sequence generator is compared with the lowest bit of the short-
ened data word and those bits below it and is rounded either up or down prior to D/A
conversion, thereby optimizing the 03D digital output signals for use with lower-reso-
lution systems. Dither endows digital signals with a noise floor close to the minimum
theoretical limit. Whether or not you use dither really depends on your application. If
you’re unsure, it’s best to use dither.
Dither can be set independently for the DIGITAL STEREO OUT and each pair of
YGDAI outputs. Set the WORD LENGTH parameters to match the wordlength sup-
ported by the digital device connected to the DIGITAL STEREO OUT or YGDAI card.
If, for example, you have a 20-bit digital recorder connected to the 03D’s DIGITAL STE-
REO OUT for use as a master recorder, set the wordlength to 20 and turn on dither for
the ST OUT DIGITAL.
The ST OUT setting applies to the AES/EBU output and Coaxial output.
1. Use the [DIO] button to locate the Dither page shown below.
2. Use the cursor buttons to select the dither on/off and wordlength
switches, and the [ENTER] button to set them.
If you are using a mouse, simply click the switches.
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