TAKE ME TO YOUR MASTER

When you assign all of your mixer's channels, subgroups, and effects returns to your mixer's master stereo outputs, you are subgrouping everything down to a pair of output channels. Most mixers offer you one more shot at processing the entire mix before it leaves the mixer by using master-bus inserts, which, like channel inserts, are commonly configured prefader.

Just like channel inserts, master-bus inserts are best used with gear that is meant to process 100 percent of the bus's signal. Therefore, master-bus inserts are commonly used for adding compression, limiting, and equalization to an entire mix.

When using master-bus inserts, use the highest-quality gear you can get. Your entire mix is running through whatever you patch into those inserts, so the quality of the processor will have a profound impact on your mix's overall sound.

Most low-cost digital mixers don't offer master-bus inserts per se, but you can usually add digital dynamics processing or EQ to the master bus using the mixer's software interface. If your digital mixer does offer master-bus inserts and they are not digital, beware the additional signal-degrading D/A/D conversions required to send your mix to an analog processor and return it to the mixer.

Some high-end digital consoles offer digital master-bus inserts that let you patch in a digital processor and thereby remain in the digital domain. There are several other ways to interface digital outboard processors with digital mixers, but they involve in-depth discussions about digital sync distribution and data formats — subjects that are beyond the scope of this article.

THE END OF THE LINE

If you use an analog console, it is almost always preferable to use its master-bus inserts instead of its master-bus outputs for routing the entire mix through analog compressors and equalizers. But those who own a low- or midpriced digital console that does not offer master-bus inserts must often use the mixer's master analog-stereo outputs for further analog signal processing of the mix.

For instance, to add analog EQ to your entire mix using this method, just route your digital mixer's master analog-stereo outputs to an analog stereo equalizer's left and right inputs and patch the EQ's left and right outputs to your mastering deck or DAW to record your mix.

You can use the same setup for inserting an analog stereo compressor (or an analog stereo-linked, dual-channel compressor) in between your digital mixer's master analog-stereo outputs and your mastering deck or DAW. Nevertheless, there is one drawback to compressing your mix using that setup: your mix will become uncompressed once its level falls below the compressor's threshold during the fade-out. The change in dynamics is usually not too noticeable on the low-level material contained in the fade.

If the change in dynamics bothers you, however, there is a work-around: you can bus all mixer channels to two analog bus outputs, route those bus outputs to a stereo compressor, and return the compressor's outs to spare mixer line inputs that are, in turn, routed to the master stereo bus.

As long as you stay in the digital domain postfader on the master faders, that is a good strategy. You don't want to use that routing if you're printing your mix to DAW or DAT by way of the mixer's master analog stereo bus outputs, because that would require a second signal-degrading round-trip through the analog and digital converters.

So far I've written about routing tracks to signal processors after their signals are already inside the mixer. I'll now detail an advanced application for routing individual tracks to signal processors before they've entered the mixer, using the versatile and mysterious mult.

I'M MULTING!

The term mult is commonly used in two ways: as a noun to denote a multiple (a signal split off from the original signal), and as a verb to denote the act of multiplying or splitting a signal. Mults are often used to split a signal into two or more paths that can then be processed differently.

For example, you might mult a lead-vocal track so that you can give each of the two or three resulting signals different EQ treatments: one suitable for verses, another for choruses, and perhaps another for the bridge. A patch bay that specifically offers a parallel routing configuration is handy for multing a signal into three parts (see Fig. 6).

Figure 6. A patch bay configured for parallel routing can split a track’s signal into three mults, each of which can be routed to a separate mixer input for different kinds of processing.

With a parallel configuration, a signal that is patched from your MDM, for example, into the top-rear patch bay jack is split into three identical signals. Those signals leave the patch bay at its top-front, bottom-front, and bottom-rear jacks. You can then route the three signals into separate mixer channels, where they can be processed separately. As each section of the song comes up during mixdown, you simply unmute the lead-vocal channel that has the desired EQ settings for that section of the song while muting the other two lead-vocal mults.

You can use the same multing method to create a killer snare-drum track. Split the snare track into two parts using half-normaled or parallel patch bay jacks (see Fig. 7). Send one signal to the mixer unchanged. Route the other signal to a compressor, followed by a gate. Set the compressor's ratio, threshold, attack, and release controls so that the attack of the snare drum's stick hit is greatly accentuated.

Figure 7. A patchbay configured for half-normaled or parallel routing can be used to split a snare track into two mults. One mult is processed with a compressor and a gate and is then combined with the unprocessed mult at the mixer to create a layered snare sound.

Then, gate that sound so that all that gets through the gate is a short burst of the accentuated attack you created with the compressor. Route the gate's output to a separate mixer channel and mix it with the original snare for a rocking power-pop sound.

If you work with a digital mixer and MDM, you don't even need a patch bay to set up the aforementioned snare-drum mult (see Fig. 8). Route the unprocessed snare track to your mixer through a digital input as you would normally do.

Figure 8. If your MDM offers simultaneously hot analog and digital outputs, you can use the analog output to process the track and then combine the processed sound with the original track’s digital signal inside your digital mixer.

At the same time, route your MDM's analog output for that snare track to the compressor and gate for treatment and send the processed signal from the gate's output to a separate line input of the mixer. That will let you mix the processed signal with the unprocessed digital input. For the method to work, however, your MDM must offer hot analog and digital outputs simultaneously.

THE CLEAREST PATH

Ultimately, the best route to use for signal processing depends on what you want to accomplish. Understanding the uses and limitations of inserts, sends, buses, groups, and mults is the first step toward creative mixing and your ticket to mastering advanced applications.

Once you have a firm grip on the basics, don't be afraid to try wild routing variations with different processors. The next new sound to hit the airwaves might be your own.

Michael Cooper is the owner of Michael Cooper Recording, located outside the beautiful resort town of Sisters at the base of the Oregon Cascades.

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