dbx Pro QUANTUM user manual Appendix C Midi Clock Info, Clock Modes

Appendix C MIDI Clock Info

QUANTUM

C.1 Clock Modes

With digital inputs, clocks are recovered from the incoming sample stream. For example, if you have a few different units digitally connected by S/PDIF, digital transfers may induce jitter into the audio stream. Syncing multiple pieces of digital equipment to a master clock reduces the jitter between them. Keeping jitter to a minimum allows for maximum fidelity. This is essential for accurate monitoring at different points along the chain.

With an analog input and downstream digital units, using the QUANTUM as a master clock will keep the digital signal accurate. While the differences in jittery sync without a master clock may be miniscule, it is better to reduce the vari- ables in favor of accuracy. Running a master clock that all downstream digital units sync to is just a good idea. Make sure that when you are using the SuperClock modes you are on the correct settings (SC 44.1, SC 48, etc.) these settings are designed especially for SuperClock. If these settings are not used, syncing errors will occur. The following chart shows the possible clock modes.

Possible Clock Modes

1.Analog In

44.1	48	88.2	96	Int Xtals
44.1	48	88.2	96	AES sync
44.1	48	88.2	96	Word
44.1	48			SC44.1, SC48,

2. Digital in - AES

44.1	48	88.2	96	AES sync
44.1	48	88.2	96	Word
44.1	48			SC44.1, SC48,

3. Digital In - SPDIF

44.1	48	88.2	96	SPDIF sync
44.1	48	88.2	96	Word
44.1	48			SC44.1, SC48,

4. Digital in - SRC - Int Xtals

96-> 48	96 -> 44.1
88.2-> 48	88.2 -> 44.1
48 -> 44.1	44.1-> 48

5. Digital in - SRC - Word

96-> 48	96 -> 44.1
88.2-> 48	88.2 -> 44.1
48 -> 48	48 -> 44.1
44.1-> 48	44.1-> 44.1

6. Digital in - SRC - SC44.1, SC48

96-> 48	96 -> 44.1
88.2-> 48	88.2 -> 44.1
48 -> 48	48 -> 44.1
44.1-> 48	44.1-> 44.1

7.Analog in - SRC - AES Sync

96-> 48	96 -> 44.1
88.2-> 48	88.2 -> 44.1
48 -> 48	48 -> 44.1
44.1-> 48	44.1-> 44.1

8.Analog in - SRC - Word

96-> 48	96 -> 44.1
88.2-> 48	88.2 -> 44.1
48 -> 48	48 -> 44.1
44.1-> 48	44.1-> 44.1

9.Analog in - SRC - SC44.1, SC48

96-> 48	96 -> 44.1
88.2-> 48	88.2 -> 44.1
48 -> 48	48 -> 44.1
44.1-> 48	44.1-> 44.1

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68 QUANTUM User Manual