Beginner's Series on Recording
Updated: Feb 11
The role of the mixer The ultimate function of the console is to control, manipulate, and route all the various audio signals racing in and out of the different pieces of equipment in the studio or synth rack—it provides the appropriate signal path for the recording task at hand. Consider mixdown. The signal flow goal of mixing is to combine several tracks of music that have been oh-so carefully recorded on a multitrack into two tracks of music that our friends, the radio stations, and the record buying public can enjoy. They all have stereos, so we ‘convert’ the multitrack recording into stereo: 24 tracks in, two tracks out. The mixer is the device that does this.
Naturally, there’s a lot more to mixing than just combining the 24 tracks into a nice sounding 2-track mix. For example, we might also add reverb. And equalization. And compression. And a little turbo-auto-panning-flange- wah-distortionTM (patent pending. It’s just a little patch I’m working on in the ol’ digital multi-effects box). It is the mixing console’s job to provide the signal flow structure that enables all these devices to be hooked up correctly. It ensures that all the appropriate signals get to their destinations without running into anything. A primary function of the console is revealed: the mixer must be able to hook up any audio output to any audio input. See Figure 1 for an example of the many possible hookups you might expect your mixer to provide.
In connecting any of these outputs to any of these inputs, the console is asked to make a nearly infinite number of options possible. We mentioned mixdown as an example above, but we do more than mix. Our signal routing device has to be able to configure the gear for recording a bunch of signals to the multitrack recorder simultaneously, like when we record a big band. It should also be able to make the necessary signal flow adjustments required to permit an overdub on the multitrack. Additionally, we might need to record or broadcast live in stereo. Fortunately, all sessions fall into one of the following categories.
1. Basics A multitrack recording project begins with the basics session. When doing the basics session, nothing is on tape yet, lots of musicians are in the room playing, and the engineer is charged with the task of getting the first tracks onto tape. You know how it goes. The band all plays together, and you record them onto separate tracks. Of course the singer will want to redo her part as an overdub later. Ditto for the guitarist. You still record everything, as sometimes the keeper take is the one that happens dur- ing basics. No pressure, just sing/play along so the band can keep track of which verse they are on, and we’ll record a more careful track in a few weeks.
2. Overdubbing For the overdubs there are often fewer musicians play- ing, fewer microphones in action, and possibly fewer band members around. It is often a much calmer experience. During basics there is the unspoken but strongly implied pressure that no one can mess up or the whole take will have to be stopped. The crowd in the studio is overwhelming. The crowd in the control room is watch- ing. The lights, meters, mics and cables all over the place complete that “in the lab, under a microscope” feeling. Performance anxiety fills the studio of a basics session. Overdubs, on the other hand, are as uncomplicated as a singer, a microphone, a producer, and an engineer. Dim the lights. Relax. Do a few practice runs. Any musical mistakes tonight are just between us. No one else will hear them. We’ll erase them. If you don’t like it, just stop and we’ll try again.
Meantime, the console routes the mics to the multi- track tape. The console creates the rough mix of the mics and the tracks already on tape and sends them to the monitors. Simultaneously, it creates a separate mix for the headphones. And we never miss an opportunity to patch in a compressor and some effects. Figure 4 lays out the console in overdub mode.
3. Mixdown For mixdown, the engineer and producer use their musical and technical abilities to the max, coaxing the most satisfying loudspeaker performance out of every- thing the band recorded. There is no limit to what might be attempted. There is no limit to the amount of gear that might be needed.
In case you’ve never seen what goes on in a big budget pop mix, let me reveal an important fact: nearly every track (and there are at least 24, probably many more) gets equalized and compressed and probably gets a dose of reverb and/or some additional effects as well. A few hundred patch cables are used. Perhaps several tens, probably hundreds of thousands of dollars worth of out- board signal processing is used.
Automation is required. And an enormous console is desired. During earlier recording and overdubbing ses- sions you might have thought, “This is sounding like a hit.” It’s not until mixdown when you’ll really feel it. It’s not until the gear-intense, track by track assembly of the tune that you’ll think, “This sounds like a record!” As Figure 5 illustrates, the signal flow associated with mixdown is actually quite straightforward. Gone is the need to handle microphone signals. Gone is the need to create a headphone mix. Nothing needs to be sent to the multitrack. The mission is to route multitrack music plus effects to the monitors. The only addition is the master 2- track machine. The point, after all, is to create a DAT, cassette, or CD master of the mix.
4. Live to 2 For many gigs we bypass the multitrack entirely, recording a live performance of any number of musicians straight to the 2-track master machine or sending it live to a stereo broadcast or the house monitors.
A Live to 2 session is the rather intimidating combination of all elements of a Basics and a Mixdown session. Performance anxiety fills the performers, the producer, and the engineer. Such freedom often leads to creativity and chance-taking, key components of a great take. So you may one day be glad you recorded the singer that day. Ditto for the guitarist. With the intent to do so many tracks as overdubs later anyway, the audio mission of the basics session is reduced to getting the killer drum and bass performance onto the multitrack. And sometimes even the bass part gets deferred into an overdub. So for basics we record the entire band playing all at once to get the drummer’s part on tape. Check out the set-up sheet for a very simple basics session. It’s just a trio—drums, bass, guitar, and vocals—and yet we’ve got at least 15 microphones going to at least ten tracks. I say “at least” because it is easy to throw more mics on these same instruments (e.g. create a more interesting guitar tone through the combination of several different kinds of mics in different locations around the guitar amp). And if you have enough tracks, it is tempting to use even more tracks (e.g. record the bass DI direct to the mixer as a separate track from the miked bass cabinet). The console is in the center of all this, as shown in Figure 3. It routes all those mic signals to the multitrack so you can record them. It routes them to the monitors so you can hear them. It routes those same signals to the headphones so the band members can hear each other, the producer, and the engineer. And it sends and receives audio to and from any number of signal processors (more is better): compressors, equalizers, reverbs, etc.
But for the console itself, the gig is actually quite straightforward: micro- phones in, stereo mix out. Of course we want to patch in any number of signal processors. Then the resulting stereo feed goes to the studio moni- tors, the house monitors, the head- phones, the 2-track master recorder, and/or the transmitter.
Board of confusion These four types of sessions define the full range of signal flow require- ments of the most capable mixer. Yet despite having distilled the possibili- ties into these key categories, the console demands to be approached with some organization. Broadly, we can expect to be frustrated by two inherent features of the device: complexity of flow (where is the signal supposed to be going?) and quantity of controls (look at all these pots!).
Complexity is built into the console because it can provide the signal flow structure for any kind of record- ing session one might encounter. The push of any button on the console might radically change the signal flow configuration of the device. In this studio full of equipment, that little button changes what’s hooked up to what. A fader that used to control the snare microphone going to track 16 might instantly be switched into controlling the bari- tone sax level in the mix. It gets messy fast. The sheer quantity of controls on the work surface of the mixer is an inevitable headache because the console is capable of routing so many different kinds of outputs to so many different kinds of inputs. 24 tracks is the norm for multitrack projects. Most of us exceed this. Number of microphones and signal processors? Well, let’s just say that more is better.
The result is consoles that fill the room—or a pair of 17" computer monitors—with knobs, faders, and switches. The control room starts to look like the cockpit of the space shuttle, with a mind-numbing collection of controls, lights, and meters. These two factors, complexity and quantity, conspire to make the con- sole a confusing and intimidating device to use. It needn’t be.
Flexibility: friend or foe? In the end, a mixer is not doing anything especially tricky. The mixer just creates the signal flow necessary to get the outputs associated with today’s session to the appropriate inputs. The console becomes confusing and intimidating when the signal routing flexibility of the console takes over and the engineer loses control over what the console is doing. It’s frustrating to do an over- dub when the console is in a Live to 2 configuration. The thing won’t permit you to monitor what’s on the multitrack tape. Or if the console is expecting a mixdown, but the session wants to record basic tracks, you experience that helpless feeling of not being able to hear a single microphone that’s been set up. The band keeps playing, but the control room remains silent. It doesn’t take too many of these experiences before console-phobia sets in. A loss of confidence matur- ing into an outright fear of using cer- tain consoles is a natural reaction. Through total knowledge of signal flow, this can be overcome.
The key to understanding the sig- nal flow of all consoles is to break the multitrack recording process— whether mixing, overdubbing, or any- thing else—into two distinct signal flow stages.
First is the Channel path. Also called the Record path, it is the part of the console used to get a microphone signal (or synth output) to the multitrack tape machine and, you know, record it. It usually has a microphone preamp at its input, and some numbered tape busses at its output. In between you find a fader and maybe some equalization, compression, effects sends, cue sends, and other handy features associated with getting a great sound to tape. The second distinct audio path is the Monitor path. It is the part of the console you use to actually hear the sounds you are recording. It typically begins with the multitrack tape returns and ends at the mix bus. Along the way, the Monitor Path has a fader and possibly another collection of signal processing circuitry like equalization, compression, and more. Keeping these two signal flow paths separate in your mind will enable you to make sense of the plethora of controls sitting in front of you on the console. Try to hang on to these two distinct signal paths conceptually, as this will help you understand how the signal flow structure changes when going from basics to mixdown. Try to break up the console real estate into channel sections and monitor sections so that you know which fader is a channel fader and which is a monitor fader.
Split consoles Console manufacturers offer us two channel/monitor layouts. One way to arrange the Channel paths and Monitor paths is to separate them physically from each other. Put all the Channel paths on, say, the left side of the mixer and the Monitor paths on the right as in Figure 8A. This is a split configuration. Working on this type of console is fairly straightforward. See the snare overload on the multitrack? This is a recording problem. Head to the left side of the board and grab the Channel fader governing the snare mic. Levels to tape look good, but the guitar is drowning out the vocal? This is a monitoring problem. Reach over to the right side of the console and fix it with the Monitor faders.
Sitting in front of 48 faders is less confusing if you know the 24 on the left are controlling microphone lev- els to tape (channel faders) and the 24 on the right are controlling mix levels to the loudspeakers (monitor faders). So it’s not too confusing that there are two faders labeled, “Lead vocal.” The one on the left is the mic you’re recording; the one on the right is the track you’re listening to.
In-line consoles A clever but often confusing enhancement to the console is the in-line configuration. Here the chan- nel and monitor paths are no longer separated into separate modules on separate sides of the mixer. In fact, they are combined into a single module set; see Figure 8B. Experience tells us that our focus, and therefore our signal processing, tends to be oriented toward either the channel path or the monitor path, but not both. During tracking the engineer is dedicating ears, brains, heart, and equipment to the record path, trying to get the best sounds on tape as possible. Sure the monitoring part of the console is being used. The music being recorded couldn’t be heard otherwise. But the monitor section is just creating a ‘rough mix,’ giving the engineer, producer and musicians an honest aural image of what is being recorded. The real work is happening on the channel side of things, and the moni- tor path should only report the results of that work accurately. Adding elaborate signal processing on the monitor path only adds confu- sion at best, and misleading lies at worst. For example adding a “smiley face” equalization curve—boosting the lows and the highs so that a graphic eq would seem to smile—on the monitor path of the vocal could hide the fact that a boxy, thin, and muffled signal is what’s actually being recorded onto the multitrack. It turns out that for tracking, over- dubbing, mixing, and live to 2 sessions, we only really need signal pro- cessing once, in the channel or the monitor path. We’ve just seen the channel path focus of tracking. Mixing and Live to 2 sessions are almost entirely focused on the final stereo mix that we hear, so the engineer and the equipment become more monitor path oriented. Here lies an opportunity to improve the console. If the normal course of a session rarely requires signal processing on both the monitor path and the channel path, then why not cut out half of the signal processors? If half of the equalizers, filters, compressors, aux sends, etc. are removed the manufacturer can offer the console at a lower price, or spend the freed resources on a higher quality version of the signal processors that remain, or little bit of both.
And as an added bonus the console gets a little smaller and a lot of those knobs and switches disappear, reducing costs and confusion further still. This motivates the creation of the in-line console. On an in-line console, the channel path and the monitor path are com- bined into a single module so they can share some equipment. Switches lie next to most pieces of the con- sole, letting the engineer decide, piece by piece, whether a given feature is needed in the channel path or the monitor path. The equalizer, for exam- ple, can be switched into the record path during an overdub and then into the monitor path during mixdown. Ditto for any other signal processing. Of course some equipment is required for both the channel path and monitor path - like faders. So there is always a channel fader and separate monitor fader (less expensive mixes often use monitor pots) The in-line console is a clever collection of only the equipment needed, when its needed, where it's needed.
Channel surfing An unavoidable result of stream- lining the console into an in-line con- figuration is the following kind of confusion. A single module, which now consists of two distinct signal paths, might have two very different audio sounds within it. Consider a simple vocal overdub. A given module might easily have a vocal microphone on its channel fader but some other signal, like a previously recorded guitar track, on its monitor fader. The live vocal track is actually being monitored on some other module and there is no channel for the guitar, as it was overdubbed yesterday. Levels to tape look good, but the guitar is drowning out the vocal? This is a monitoring problem. The solution is to turn down the monitor fader for the guitar. But where is it? Unlike the split design, an in-line console presents us with the ability to both record and monitor signals on every module across the entire con- sole. Each module has a moni- tor path. Therefore each mod- ule might have a previously recorded track under the con- trol of one of its faders. Each module also has a channel path. Therefore, each module might have a live microphone signal running through it.
To use an in-line console, you must be able to answer the following question in a split sec- ond: “Which of the perhaps 100 faders in front of me controls the guitar track?” Know where the gui- tar’s monitor path is at all times, and don’t be bothered if the channel fader sharing that module has noth- ing to do with the guitar track. The monitor strip may say, “Guitar.” But you know that the channel contains the vocal being recorded. It is essential to know how to turn down the guitar’s monitor fader with- out fear of accidentally pulling down the level of the vocal going to the multitrack tape.
One must maintain track sheets, set-up sheets, and other session doc- umentation. These pieces of paper can be as important as the tape/hard disk that stores the music. However, rather than just relying on these notes, it helps to maintain a mental inventory of where every micro- phone, track, and effects unit is patched into the mixer.
Much to the frustration of the assistant engineer who needs to watch and document what ’s going on and the producer who would like to figure out what’s going on, many engineers don ’t even bother labeling the strip or any equipment for an overdub session or even a mix session. The entire session set-up and track sheet is in their heads. If you have enough men- tal RAM for this, try to do it. It helps you get into the project. You are forced to be as focused on the song as the musicians are. They’ve got lines and changes and solos and lyrics to keep track of. The engineer can be expected to keep up with the microphones and reverbs and tracks on tape. This comes with practice. And when you know the layout of the console this intimately, the overlapping of microphones and tracks that appears on an in-line console is not so confusing.
Sure the split console offers some geographic separation of mic signals from tape signals, which make s it a little easier to remember what’s where. But through practice you a e going to keep up with all the details in a session any way. The in-line console becomes a perfectly comfortable place to work .
Getting your ducks in a row If you’ve dialed in the perfect equalization and compression for the snare drum during a basics session, but fail to notice that you are pro- cessing its monitor path instead of its channel path, you are in for a sur- prise. When you play back the track next week for overdubs, you’ll find that that powerful snare was a monitoring creation only and didn’t go to tape. It evaporated on the last playback last week. Hopefully you remember and/or document the settings of all signal processing equipment anyway, but more helpful would be to have had the signal processing chain in front of the multitrack tape machine, not after. No worries.
Through experience, you’ll learn the best place for signal processing for any given session. Equalization, compression, reverb, the headphones—each has a logical choice for its source: the channel path or monitor path. And it varies by type of ses- sion. Once you’ve lived through a variety of sessions it becomes instinctive . Your mission is to know how to piece together channel paths, moni- tor paths, and any desired signal processing for any type of session. Then the signal flow flexibility of any mixer, split or in-line, is no longer intimidating. By staying oriented to the channel portion of the signal and the monitor portion of the signal, you can use either console to accomplish the work of any session. You can focus instead on music making.