Our Guided Tour of Mixer Helps You Go With the Signal Flow
Digital Differences

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Although digital mixers perform nearly all of the same functions as analog units, they do so differently. They also offer many features not found on analog mixers. It’s far beyond this article’s scope to give a complete account of signal routing in specific digital mixers, but I’ll point out a few essentials using the Yamaha 02R (see Fig. A) as an example.

Analog audio signals don’t flow through digital mixers. Analog signals entering a digital mixer are converted to digital information in a data stream, and they stay that way until converted back to analog signals. If you track to a digital multitrack machine, using digital buses and mixing to a digital recorder, the only reason to convert the digital signals back to analog is for monitoring. (Monitor speakers must be analog.)

FIG. A: This Yamaha 02R digital mixer is configured for use with two ADATs, which are synched using SMPTE time code printed to track 8 of one recorder. Also shown are the connections to an aux send, a computer, headphones, control-room monitors, and various input sources.

Digital consoles have no analog circuits between the A/D converters and the DACs. When you push up a digital fader, you’re simply moving a vertical data encoder assigned to adjust amplitude. You can reassign this fader to adjust some other value—such as monitor-send level—and most digital mixers exploit this capability with several different fader assignments levels. For example, level 1 might assign faders 1 through 16 to channels 1 through 16, while at level 2 the same faders control channels 17 through 32, and at level 3 they act as master sends for the aux and recording buses.

Many digital mixers feature software-based effects. For example, the 02R has two complete onboard multi-effects processors and enough 4-band parametric EQs, dynamics processors, and delays to patch one of each across nearly every input and output on the mixer—all without plugging in a single cable. Yet most digital mixers have few, if any, analog insert points. Adding inserts (and direct outs) means more D/A converters. If you normally patch in your favorite vintage compressors on mixdown, you may not be a happy camper. This point is a deal-breaker for many people.

Because digital-mixer settings are information stored in memory, they are perfect for “snapshot” and dynamic automation. Once you set the mix parameters, you can take a snapshot of them and name and store them as a file. In most cases, you can back up these settings to a computer for safekeeping. You could return to the mix years later, press a few buttons, and shazam! Your settings load, and the mixer is ready. The same goes for dynamic automation, in which you usually store the fader, EQ, pan, and mute moves in memory (or in a MIDI sequencer, if the mixer has MIDI automation).

Like analog mixers, digital mixers have analog mic and line inputs, but they usually offer additional channels accessible only through various I/O cards. If you want to use a digital mixer with an analog multitrack deck, you need analog I/O cards. You’ll probably connect the mixer to digital recorders, so you’ll need the appropriate interface: ADAT, TDIF, AES/EBU, or S/PDIF. A few digital mixers boast lots of digital inputs, but most need optional I/O cards.