Whether you’re working with acoustic or electronic tracks (or a combination of both), some principles of mixing apply across the board. There are six essential rules that I adhere to in any mixing situation. No matter how great a mixmaster you think you are, if you ignore these basic principles, your end product will suffer. So, let’s run them down quickly.

1. Be mentally prepared to tackle the mix. Get yourself in the right frame of mind. Make sure that you’re properly rested. This also means taking breaks from the mix periodically; I’ve found that a breather every two to three hours is sufficient. Avoid interruptions: mixing requires just as much concentration from the engineer as laying down a solo does from the musician. So turn off the phone. Finally, make sure the mood is right. Get a comfortable chair, dim the lights, and fire up the lava lamp. (Okay, the lava lamp is optional.)

2. Know your client. What kind of music are you working on? If it’s a band project, has the band previously released a record that you can listen to? What are the producer’s goals? You can completely alter the sound of a record in the mix, so you need to know what direction to go before you start working.

3. Be familiar with the monitors. If you’re not working in your own studio, or if the producer brings unfamiliar speakers, give yourself a crash course in monitoring on the equipment. Pop in a CD that you are thoroughly familiar with; listen for exaggerated or muffled frequencies, paying particular attention to the low- and high-end content. Make mental (or even written) notes. Once you feel that you know the speakers’ response, start working on the mix immediately.

4. Monitor at low levels. There are three reasons for keeping the monitors low while you mix. First of all, you’ll avoid a case of listening fatigue (not to mention other health-related problems associated with loud music). Secondly, just about any mix sounds good when it’s cranked up; the stellar mixes are the ones that sound good both loud and soft. Third, with the speakers at loud volumes you won’t catch level problems. I was mixing a radio promo recently and thought I had a great mix going, but I was completely crushed when I lowered the monitors to a normal level—I couldn’t even hear the announcer’s voice.

5. Reference your mix to similar commercial mixes. Listen to mixes that are similar in style to what you’re working on. Again, if the band has other material you can use, great. If your console has a 2-track input for a CD player, use it. This way you can A/B between your own mix and the one you’re striving to emulate. This step obviously isn’t appropriate for those projects you have no intention of patterning after someone else’s work, but it’s often useful when producing commercial music, especially when you have to please a record label executive.

6. Reference the mix on a variety of systems. This is the most important point to remember: a well-balanced mix will sound good on poor monitors and great on good monitors. Check what you’re mixing through several systems of varying size and quality. Before I complete a mix, I’ve listened to it on my studio monitors, a pair of headphones, a boom box, and my car stereo. If I really want to go crazy, I’ll burn a CD and check it out on whatever system I can find. (I’ve actually done referencing in the electronics department at Sears.)

If you’re mixing on a computer, you have the advantage of building your mix during the recording process so that when it finally comes time to print to 2-track, only minor adjustments will be needed. I once produced a project when we didn’t even have a dedicated mix day; instead, I took an hour to automate the vocal track and then printed the song to DAT.

Even if you’re not working with a computer-based system, start getting some ideas together as you record. One of the best bits of advice I can impart is to periodically record rough mixes during tracking. All too often, after listening to the same song for weeks or months, we lose the fresh perspective that we had at the beginning of a project. Rough mixes are the perfect way to recall that lost perspective. Check in with them often to find out what your ideas were weeks ago.

What Goes Where?

When working entirely with sequenced MIDI parts, you have the option of mixing tracks virtually without ever recording them to a multitrack. The benefits of mixing directly from the sound modules are obvious. For one thing, your signal path is shorter, so your chances of collecting sonic garbage drop substantially. In addition, sticking with MIDI tracks leaves more audio tracks available. But most important, it means you’re not committed to anything—you can edit and automate synth sounds and sequences in ways that would be difficult to do with audio tracks, and you can do it at the last minute if necessary. (If you’re performing virtual mixing with a digital audio workstation, make sure your system has the ability to mix live inputs and that you have enough I/O available.)

However, many professional engineers like to print MIDI sequences to multitrack audio media (especially analog two-inch tape). Sometimes it’s unrealistic for the personal-studio owner to go this route, but it has several advantages. In a small studio with limited resources, for example, recording to audio multitrack allows you to apply outboard effects to individual tracks and submixes, freeing up your limited supply of effects processors for reuse at mixdown. In addition, submixing to tape or disk can simplify your final mixdown process. If you print to analog tape, of course, the tape recorder operates as a signal processor in the sense that it can add a desirable sonic quality.

Whether you mix virtually or print your sequencer parts to tape, it’s generally better to clean up the signals at the sound modules rather than at the mixer. Selective filtering and compression can be used to remove unwanted frequencies or dynamics before a sound leaves the module. However, I usually try to save elaborate effects processing for the mixing environment, where I can employ dedicated units (unless I’m mixing on a DAW, where DSP is a precious commodity—in which case I might do some processing at the modules and some at the mixer). It’s a balancing act, but it’s better to have too many options than too few.

If your mixer doesn’t offer dynamic automation, you can use MIDI Control Change 7 (Volume) and 10 (Pan) messages to automate your sequenced tracks. The drawback to this is that a mixer channel will remain open even when no signal is present, which is not the case when you manually ride the faders. With an analog mixer, you’ll get some hiss; to fix this, you can use noise gates or expanders at the channel inserts.

In general, it’s good practice to maintain as many dedicated instrument channels as possible. Granted, sometimes you may have no choice but to submix several parts to a stereo output, for instance. Just avoid unnecessary submixing; the more signals you have to work with at mixdown, the better.

There are three basic kinds of electronic sounds: emulations or samples of acoustic or electric instruments; completely artificial sounds; and emulations or samples of real-world, nonmusical sounds (a dog barking, for example). The mix engineer needs to approach each type differently.

When working with acoustic and electric instrument sounds, the goal is usually to replicate an accurate image of each instrument, positioning it in a realistic place on a virtual soundstage and making sure its frequency content is similar to what it would be in the real world. You’ll then give the recorded instrument a volume and depth on that stage by using level control, reverb, and sometimes other processing, such as delay. (This is not a hard-and-fast rule, obviously; there are no rules in the creative arts.)

The same philosophy usually holds true if the "acoustic" or "electric" instrument happens to be a sample or synth patch. For example, even though the Roland JV-1080’s grand-piano patches are electronic samples, I’d probably still EQ them like real pianos and put them in realistic positions in the stereo image, unless I was trying to achieve a weird result. However, the methods you use ultimately depend on the style of music you’re producing: for alternative and urban styles, perhaps the piano would need to be equalized like a guitar and spread across the entire stage.

When working with completely synthetic sounds, a different set of rules applies. Trying to place these instruments in a realistic spot on a "stage"—an acoustic environment where they wouldn’t normally be heard—is pointless. In addition, there are no real-world templates of synthetic sounds on which to base EQ settings; I mean, what is a Telefunken or a Space Warp Pad supposed to sound like, anyway? The same is true of nonmusical samples (unless, of course, one of your band members is really a barking dog). The only exception here is when you are creating music for picture and want to position the effects to match the action.

Working with synthetic sounds essentially gives you carte blanche to create exciting mixes with sounds coming from all over the stereo image and frequency spectrum. And using creative dynamics control and multi-effects processing, you can mold those sounds into practically anything you want.

You have much more creative liberty with a mix of electronic instruments than you do with a mix of acoustic ones. I like to create a natural-sounding blend of all the elements. Artists such as Beck, Nine Inch Nails, Jane’s Addiction, and Alanis Morrisette often employ contrasting timbres that don’t blend smoothly—but for a lot of music, a smooth blend is preferable.

In most cases, instruments and sounds should not compete with one another either spatially or spectrally. You should be able to hear every part of a mix and immediately identify which instrument is which. To do this, I try to conceptualize the mix as a three-dimensional stage (see Fig. 1). Panning instruments moves them across the width of the stage; altering their level and adding reverb or other delay effects determines how far back they are. The vertical axis represents frequency response (for example, cymbals would be toward the top of the stage, with the kick drum sitting near the bottom). This way you can graph the stage from either the front or above and see the two most important relationships of a mix: frequency/pan position and volume/pan position.

The goal is to make sure that no two components are centered at the exact same place in either graph. I don’t mean that things can’t overlap—the lower keys of a piano will inevitably be situated in the same area of the frequency spectrum as the bass—but elements shouldn’t blatantly sit on top of each other. This is what causes a mix to become cluttered and muddy sounding. A clear mix is achieved through careful planning and adjustment of level, pan, and EQ.

Many people don’t realize just how much EQ and level can affect the placement of an instrument in the stereo field. To check this out yourself, try the following experiment. Put the faders of your bass and kick drum tracks up with both channels panned to center. Boost them both by 15 dB at 200 Hz and turn up your monitors. You’ll notice that it becomes difficult to distinguish the hit of the kick drum. Now pan the bass to nine o’clock and the kick drum to three o’clock. When you do, the kick drum hit returns. Finally, pan them both back to center and pull down the level of the bass track; you can again hear the kick drum better when the bass is lower.

This experiment illustrates how instruments can occupy the same frequency ranges, provided they aren’t at the same spatial position in a mix (and vice versa). I’ll discuss specific EQ applications below, but this is important to keep in mind when panning tracks.

In general, instruments that comprise the rhythm section are kept toward the center of the mix (see Fig. 2). Specifically, drum parts, bass parts, certain pianos, and loops should be spread no further than ten and two o’clock. In fact, try putting monotonous loops in mono; this opens up the horizontal axis for the supporting characters (guitars, piano, strings, and so on). Whatever you do, don’t pan your drum tracks across the entire stereo image: have you ever seen an acoustic drum kit with toms that run from stage left to stage right? Keep the kit in the middle.

As a rule of thumb, any part that has a heavy low-frequency content should be situated toward the center of the mix. Simply panning the two signals is a prescription for trouble. True, Beatles engineer Geoff Emerick split the drums and bass to opposite channels on certain Beatles tunes. However, his drum and bass panning was almost certainly done out of necessity for bouncing tracks to overcome track limitations.

Lead vocals are generally put right up the middle; anywhere else makes them just distracting to listen to. Although instrument solos are usually panned dead-center, I prefer to spread them slightly to either side. Often, a solo will be played along with the lead vocal, and if both are in the center they will be competing with each other. (Many solo instruments have a frequency range similar to that of the human voice.)

Finally, the outside edges of the mix are usually reserved for effects returns (particularly reverb), for certain types of percussion, and for high-frequency background vocals (à la the Bee Gees). Be careful when placing sounds completely in one channel or the other, especially if you’re also processing them with multi-effects; in these instances, delays and reverbs that are panned opposite the source sound can cause phase cancellation.

Auto-panning synth patches should be addressed with caution. At what spectral position do these sounds start their journey, and where do they end up? This path must be clear of other sounds in the same frequency range; otherwise, dropouts will occur. Once you have a clear idea of where you want to place everything, it’s time to make sure that instruments sitting in similar places aren’t competing for room in the frequency spectrum.

Proper EQ means more than just getting a great sound from a track; it’s about eliminating congestion in the mix. I want to stress the importance of subtractive EQ. In general, your mix will benefit more from cutting than from boosting. To tweak a sound with a parametric EQ, I usually start by doing the opposite of what I was taught in school: I turn the EQ gain down all the way and sweep the frequency knob, so I don’t even think about boosting anything unless I really have to. However, if you cut enough frequencies, you’ll probably need to make up gain at some point. Fortunately, many digital mixing consoles and DAWs provide a "gain makeup" capability as part of the EQ section.

With electronic replications of acoustic instruments, your best bet is probably to retain the authenticity of that instrument’s natural sound. This does not mean that the samples don’t need equalizing: although they are supposed to be accurate, pristine recordings of acoustic instruments, many are flawed. Basically, you want to eliminate frequencies that aren’t needed. What is the instrument’s primary range? In other words, which frequencies are needed to get it to cut through a mix, when that is desired, or to keep it back in the mix when it is supposed to be part of a pad? Once you determine the range, you can whittle it down to the necessary frequencies.

Two of the most important sounds in a mix are the kick drum and the bass part, and there should be a synergy to their relationship. These two tracks constitute most of the low-frequency energy in a mix. You need to decide which of these tracks will be the primary source of low end. For a traditional mix, I usually opt for bass, simply because there is more motion to it, and spotlighting it makes the low end more interesting.

On a bass part, I find that rolling off frequencies below 50 Hz is a good start. Boosting frequencies in the 300 Hz to 1.5 kHz range (admittedly a large range) will increase the track’s clarity, and pulling them out will round out the low end. Once I have the bass sound, I work the kick drum in as support, accenting mid frequencies (1 kHz) and boosting a little around 80 Hz (3 to 6 dB, with a narrow bandwidth).

On the other hand, if you’re producing urban music, the kick drum sample or synth patch should be the more pronounced low-frequency element. Because many hip-hop beats are derived from premixed loops, you’ll want to boost the track by about 3 dB at 120 Hz. Loops also have little high-end clarity, so you may have to roll off upper frequencies with a shelving filter (usually above 7 kHz). A mid-range boost might also be in order. Most other electronic percussion instruments are fine with little or no EQ; if EQ is needed, it’s usually a boost at 7 kHz or higher.

Certain synth pads—especially organ sounds—tend to be heavy on the low-end content. You’ll probably find that, although they sound really fat by themselves, they just don’t sit well with the rhythm instruments. Try rolling off frequencies below 300 Hz or boosting the track in the 2 kHz to 3 kHz band and lowering the fader level.

Digital pianos can often present the same problem in a mix, especially when the lower half of the keyboard is being used. As long as the piano isn’t the only instrument playing, my advice is to roll off the low end. I recently used snapshots to automate the EQ of a piano track in a rock song. The piano started the song out and needed to sound full, but when the rest of the band came in, it totally clashed with the bass. So I simply set up two snapshots—the second one with a highpass filter engaged—and performed the change on the fly.

One very useful application of EQ is reducing hiss from sound modules. Although expanders and gates are an option, you’ll find that rolling off frequencies above 10 kHz is sometimes a better approach. Keep in mind that this will work only on synth outputs handling signals that have no frequency content above 10 kHz (such as drum tracks, bass parts, and guitar parts).

Remember, every change you make to one track—no matter how small—will affect the other tracks as well. A tweak to the piano will change its relationship to the bass, which may alter the way the bass sounds. So if you make major changes on soloed tracks, be sure to check the sound in the mix immediately.

Keep it Under Control

When used on acoustic instruments, compressors work to smooth the dynamics of a performance. Contrary to what many people think, electronic instruments have a good deal of dynamic range. You probably won’t have to squeeze anything to death as you would with an electric bass-guitar track, but slight compression of certain sounds can tighten up your mix. Synthesized strings generally sound good compressed at a light ratio (2:1 at -6 dB). If you have a live piano track, you may also want to process it with a little compression (-6 dB threshold, 3:1 to 4:1 ratio), especially if the musician performed with a lot of dynamic feeling.

Compression is often used in an electronic instrument mix to blend several synth outputs together by performing a submix of the desired tracks, busing them to a stereo pair, and patching a compressor across the two channels. Many people use this method to combine sampled sounds, particularly if the samples were derived from a variety of musical styles. I often do it with drum sequences if the samples didn’t all come from the same kit. This achieves two things: first, it ensures that the kit will sound cohesive; and if I want, it lets me generate an intentionally overcompressed pumping sound across the drums (a typical hip-hop sound).

Gates are commonly used on synth outputs to quiet or eliminate noise if no mixdown automation is available. Getting rid of extraneous noise is a priority; I have heard some really nasty sounds come out of certain inexpensive sound modules. You don’t need to gate the outputs if the modules are active throughout the entire song, only if there are extended periods of inactivity.

Although you could use an expander for this purpose, a gate doesn’t affect the dynamics of the performance the way an expander does. Make sure that the gate’s attack and release times are set properly; otherwise you may cut off part of the performance.

Finally, for those folks producing urban music, it’s not a bad idea to patch a limiter across the stereo bus—just enough to catch peaks from the kick drum. After all, you don’t want people getting mad at you because your mix blew their woofers out. (For a more detailed look at using dynamics processors, see "Conquering Peaks" in the December 1998 EM.)

When approaching a mix, I suggest you start by determining where you want to place everything on the stereo field and then pan the tracks accordingly. Push all the faders up, and get a rough mix going. Next, use EQ to tweak the sounds in context with the rest of the tracks so that nothing is clashing. If you hear something funny with any of the tracks, solo that track, isolate the problem, and fix it. When you’re done, pull all the faders back down.

Next, determine which track (or tracks) to mix the song around. Most people agree that you should build a mix around the most important element—whatever will sell the song. Doing this ensures that you won’t be caught with a great mix that has absolutely no room for the prized track. So generally, pop music (especially ballads) should be mixed around the vocal; jazz around the soloist; and rock, urban, and alternative around the rhythm instruments (drums, loops, and bass).

Bring the volume fader of your focal-point track up to about 80 percent. (If you decided to mix around the rhythm section, start with the kick drum and bass guitar.) Apply whichever multi-effects processing you want, but don’t obsess over the levels of the effects returns; they’ll need to be readjusted anyway once you start adding more tracks to the mix. Then start bringing in the rest of the components, adding effects where needed.

If you’re building around the rhythm instruments, follow the kick drum and bass with the snare and other drum tracks. Then bring in supporting instruments (piano, guitars, strings, and so on), followed by percussion, lead instruments, and solo instruments. Finish up by adding background vocals, samples, and sound effects.

When building around a solo instrument or vocal, I find it best to bring in some sort of accompaniment first, like acoustic guitar or piano. Follow that with the rhythm instruments, as outlined above, and finish with the supporting cast. If all your levels are good, you should still feel the energy of the first track you put up even after you’ve added all the other instruments. Don’t forget to check the mix in mono, especially if you think your recording could be broadcast; many radio and TV stations do not broadcast in stereo.

Once you’re reasonably happy with what you hear, you’ll want to establish the mix’s overall frequency parameters. How much high end do you want? How much low end? True, the mastering engineer usually takes care of these things, but most professional mix engineers will use a parametric or graphic EQ across the stereo bus before printing the mix to 2-track. This allows them to set high and low boundaries for the mix—a particularly smart move when working with electronic instruments, where the frequency responses of the tracks can run the gamut. (It will also help you EQ and set the levels of the extremely high- and low-frequency instruments.)

Again, find a CD with similar content and audio quality to the project you’re working on. Listen to the overall volume of the upper and lower frequencies. Then compare that CD with the mix you have going, and make minor adjustments to the stereo EQ where needed. A graphic EQ—I prefer the dbx 2231—is an excellent tool for this application.

A lot of hip-hop, dance, and R&B music has extremely heavy low-end content. This contributes to these genres’ distinctive sounds, but loud low end doesn’t equal good low end. In other words, don’t boost 9 dB at 120 Hz during mastering to get the kick drum to stand out more; go back and fix it in the mix. A good mix should require very little tweaking at the stereo bus.

Finally, a little compression (-3 dB, 1.5:1 ratio) across the stereo bus can compensate for subtle level changes that you may not have caught in the mix. Alternatively, as I mentioned earlier, limiting may be in order. (Be sure to set your threshold just below the peaks you want to eliminate.)

The most important thing you can do for any mix is put it to rest once you’re done. Let it sit for a few days, allow your head to clear, and then listen to it with fresh ears. At that point, you’ll probably want to make a few thousand adjustments, but that’s fine. What’s essential is that you take a break from the project.

When all is said and done, a mix of electronic instruments employs many of the same techniques as a mix of acoustic instruments. In fact, an electronic mix actually allows you to be more creative. If you keep in mind the basic principles I’ve outlined here, you should be able to construct a solid, three-dimensional mix that jumps right out of the speakers.

This article presented courtesy of Electronic Musician magazine.