Category: Talkback Posts

The High Wire

Mixing is a balancing act.  Like an acrobat walking the tightrope, the mix engineer must strive for balance.  A push in one direction can mean a pull in the other, and it’s easy to lean the wrong way if you’re not careful.

Balance starts with the trusty eq.  Faders, pan pots, compressors, and effects are all powerful mixing tools, but they can’t easily fix bad tone.  Hidden energy can rob your mix of punch and sparkle, and make it difficult for featured tracks to sit well in the mix.  Good tone maximizes impact, size, and emotion.

Once you get the frequency balance sorted out, your mix will have more detail and depth – compressors will have less work to do and fader moves will be smoother because balancing the frequencies can minimize jumps in level.  Let’s look at some ways we can use eq to get a spectrally balanced mix.

What is Spectral Balancing?

Spectral balancing is a fancy term for using an eq for dialing in, or carving out, a frequency space for each element of a mix so everything blends together in a pleasing, balanced way, without too much energy in any one area of the frequency spectrum.

An eq is a tone control. The first introduction to spectral balancing for most people is the bass, mid, and treble tone controls on their stereo system.  Those 3 dials cover the entire spectrum of highs, mids, and lows. A spectrally balanced mix would not have too much energy in any one of those general areas, and when listening, you wouldn’t feel the urge to boost or cut any of those bands to make it sound better.

At the mix stage, each element of the mix can have its own tone controls, and since that track blends with the other tracks, a careful ear must be placed on how those elements all work together.   What you are aiming for is a mix that sounds balanced throughout the entire frequency range, a cohesive blend with all tracks playing.

Get A Second Opinion

I recommend using a spectrum analyzer when mixing.  There are many spectrum analyzers available today, some are even free, so using one should be mandatory.  The visual representation provided by the analyzer serves as a confirmation of what you are hearing, and can indicate the exact frequency you are trying to control. Insert it on your mix bus at the end of the chain to get a visual display of the frequency content of your entire mix or anything that passes through the master fader.

When you mix or solo a track or group, the analyzer will show the frequency content of that element, so it is a handy reference at any time during the mixing process.  It will also reveal rumbles, hiss, and identify spikes for you if you miss them or your speaker/room combination isn’t revealing them.  Between what your ears tell you and what the analyzer is showing you, you should be able to pinpoint problem frequencies and enhance tone quickly.

Tip: A pre-mastered, spectrally balanced mix should have a general frequency curve that has a slight tilt downward from low to high.  If it were a flat curve, it could end up very harsh and bright after limiting and mastering.

Carving Out a Sound

Today’s large track counts and close miking techniques require weeding out competing frequencies for a clear mix.  You might find a buildup of low frequencies, and some tracks may need energy removed from bands that have little effect on the tone. Sometimes a boost in the tonal area is desirable where the body of the instrument resides.

Two of the most common eq problems with mixes are boominess and harshness.  Going through the tracks and sorting out the low mids and high mids can really clear up a track without losing any of the size or the sizzle. Listen closely to the sound of the track, and try to “hear ahead” to what you could do to make it sound better, or make it blend better.

Here are some techniques for spectrally balancing your mix with individual track eq.  To protect your speakers and your hearing, you may want to turn down your monitors when you boost and sweep as you hone in on frequencies:

Corrective EQ:

Clean up obvious issues with the tracks. This is where you attack obvious frequency issues.  This could mean rolling off the extreme bottom rumble, or getting rid of any problems that distract from the performance, like noise, finger squeaks, sibilance, etc.  Tip:  Go track by track, checking for any obvious problems.  Use the filters to remove subsonic rumbles or noise.  Tidy up obvious distracting problems.

Find and remove hidden energy. This is the powerful step of removing unnecessary excess energy.  It may not always be obvious where it is.  Many times it is low frequencies, but it can be in any band unnecessarily taking up “space”.  Look for energy in the low midrange to weed out.  Learn to find it and remove it, and you will have more “room” in your mix.  Tip:  Sweep through the bands at full cut, and find an area where the cut does the least damage, and the sound is still fairly natural, even with that band cut.  Now that you’ve found the area, bring it back in, cutting only as much as needed to help the blend with the other tracks, and use a fairly narrow bandwidth.

Cut ugly frequencies. This is where you cut areas of the spectrum where there is bad tone.  This would be an area you would not want to highlight or bring out, like honking, ringing, or boingy frequencies jumping out.  Usually, you’ll find it in the midrange, not at the extremes.  Tip:  Sweep through the bands at full boost, medium bandwidth, looking for a really bad sounding area, then cut this area with a narrow bandwidth.  Adjust bandwidth and amount of cut by ear.  If needed, find a frequency above or below the cut frequency to boost to bring back some fullness or presence the cut may have removed.

Know Your Limits. Balancing the extreme top and bottom ends of the mix spectrum is important. Cymbals, shakers, and other high percussion are usually the top instrument (over about 12-14KHz), and the kick and bass usually fill the space in the bottom (under about 60Hz).  Everything else fits in between there.  Tip: Sweep with high and low pass filters until you start to hear a change or degradation of the tone, then back off a bit.  Rolling off energy at these extremes will make room for those instruments that need that space. For example, using a low cut filter on a vocal will help keep plosives from popping out.

Creative EQ:

Bring out the tone. Once the tracks are cleaned up and excess hidden energy has been removed, it’s time to boost for good tone.  For example, once sibilance has been minimized, it may now be possible to brighten up the vocal for detail and intimacy.  Find an area where the instrument sings.  Many times this is in the lower midrange area, with clarity in the high mids.  Tip: Sweep through the bands with a medium boost, then back it down to a slight, gentle boost once you find a happy area where the body of the instrument lives.  Start with a medium bandwidth to zero in on an area you like, then us a fairly wide bandwidth (Q) for the tone boosts.  Resist the temptation to boost excessively.

Use EQ For Effect. Telephone voice comes to mind, where all the bands are cut except a small band in the upper mids.  Other dramatic effects are possible, from deep bass accents to automated filters and sweeps.  To bring an element forward in the mix, roll off the bottom.  To send an element back in the mix, roll off the top.  Or cut some of the mids, and enhance the highs and lows (smiley face curve), then bring the overall gain back up for a big sound that doesn’t hurt the ear when cranked up and stays out of the way of the vocal.

Tip: Use eq for height and depth – brighter sounds seem taller and closer, bassier and duller sounds seem lower, bigger and father away.

Some engineers say you should never eq a track in solo. Yes, you can certainly solo a track to hear problems like rumble, high frequency noise, honkyness, dullness, etc. while EQing, but it is a good idea to do your creative EQing in context of the other tracks. Let the mix play, and dial in the EQ on that track until it sits well among the other tracks and is clear (or distant, or however you want it to sound) without solo’ing the track. No one will ever hear the track in solo, so the blend is what we are going for.

Tip: Sometimes your first instinct may not be your best choice, and the opposite approach may be the better move for a track. For example, if a track is too bassy, you may at first think to add high end. But you may want to reduce the low end instead, then turn the track back up. Conversely, if a track is brighter than it is full, you may want to reduce the high end and turn the track back up a bit instead of adding bottom, and use the body that was naturally captured rather than inflating the bottom with EQ.

After you have the track sounding better, adjust the output gain on the eq so you can pop the eq in and out, and the level remains consistent.

Hear The Band

Try to describe the sound you are hearing. For example, use words to describe the sound like dull, harsh, boomy, round, warm, thin, or sizzly, or whatever it sounds like to you. If you can describe it, you can fix it.

To train your ears to hear frequencies quickly, it helps to break the frequency spectrum into larger general areas (low, low mid, high mid, and high) at first, and get used to hearing those broad ranges of the spectrum. Then learn to identify the 10 octave bands, and you’ll be carving better sound faster and easier. Soon you will learn the sound of frequency ranges and how they “feel”. Those descriptions will help you learn the 10 octave bands. Once you can associate each frequency band with a feeling, it’s easier to clear up mixes. 

Here is a general description of how to hear the spectrum, broken into 10 musical octaves by frequency and approximate piano note range:

Deep Bass (20-40Hz, A0-E1) – Not a lot of musical information way down here, but energy in this range can add to the perceived size and impact of the mix.  Too much energy here will prevent you from getting a competitively loud mix, as the speakers will be working hard to reproduce that energy.  This octave can be cut from most instruments, and many loudspeakers don’t reproduce this range.  Low B on a 5 string bass is about 31Hz.

Low Bass (40-80Hz, E1-E2) – This is the range that has the pants-rippling, table shaking low end you feel at concerts.  Bass and kick are neighbors here, and it can be gently rolled off any other tracks that might occupy too much space here, like close miked guitar cabinets, rumbling toms, close miked hihats, vocals, etc. Low E on a bass is about 41Hz.

Bass (80-160Hz, E2-E3) – The fundamentals of lower pitched instruments are in this octave.  The E string on a guitar is about 82 Hz.  This is the thick and beefy area where the “weight” of the instruments and vocals lives.  Space-crowding low resonances are down here.  The warmth and depth of the sound is here, but too much energy in this area can diminish clarity.

Upper Bass (160-300Hz, E2-E3) – This is the mudrange, and also where the “thump” is.  This range is a good place to cut muddy buildup, or add chest thump to a snare.  Many times, instruments and vocals that are “boomy” or lumpy can benefit from a dip in this range.  Too much energy in this octave will distort some speakers, making the woofers bottom out on the punch, which will rob your mix of volume and definition. Reduce this range to retain the fullness and volume, but lose the “chuff”.  The fundamental of the toms lives here.  Middle C is 261.63Hz.

Low Midrange (300-600Hz, E3-E4) – Here lives much of the fullness and body of the sound. Too much and things start to sound honky or nasal.  This area is where you would find vocal resonance issues, hihat or metal clang, or buildup from the other tracks that you can cut to make it sound better.  This is a good place to cut on kick and toms.  The richness of vocals and other instruments lives here.  A=440Hz.

Midrange (600-1200Hz, E4-E5) – There is a lot of competition for space in this critical band, so sorting out this octave will help vocals and lead instruments cut through without having to be pushed.  Strident or harsh pitches can build up here.  Reducing energy in this area on backing tracks can help carve a space for the featured tracks. This is the range to boost for clarity on bass guitar.

Upper Midrange (1200Hz-2.4KHz, E6-E7) – The ear is very sensitive in this area. Too much energy in this band gives a hard edge to a mix, and can be fatiguing or possibly damage your hearing if abused.  The clarity of vocals is here, but so is the bottom end of sibilance.  Gently dialing out this area on brighter instruments like electric guitars and cymbals can help minimize clutter against the vocal or lead instruments.

Presence Range (2.4 KHz-5KHz, E7 and higher) – The bite on electric guitars, the attack on drums, and presence and liveliness live here.  This is the region where vocal sibilance resides, and is the upper end of the range of most instruments.  The snap of the kick beater is up here.  The highest note on a piano is C8, or 4186Hz. Too much energy in this octave results in a fatiguing harshness.  You can add warmth by attenuating this region a bit.  Critical detail lives here for clarity on words, transients, and articulation.

Highs (5-10KHz) – The brilliance is here, and the detail.  Vocal sibilance can also be up here, as well as hiss and distortion artifacts.  The brighter edge of guitars and vocals, and brightness live here.  This area can be rolled off of bass guitar and other elements for a less pointy, vintage sound.

Extreme Highs (10-20KHz) – The air, the sizzle, and the extreme highs live here.  Cymbals and all the other components that bring a sense of quality and accuracy reside here.  Boost 10KHz to bring out the point on the snare.  Be careful to avoid rolling off too much in this region as you run the risk of dulling the impression of quality in the recording.  Too much energy here may actually reduce definition.

Summary

When you find yourself chasing your tail on a mix, or the faders just keep creeping up, go back to the eq to carve a space for everybody, and get it under control!

For more detailed information, magic frequencies, a breakdown of the various types of EQs, and further instruction, click here: Spectral Balancing Book.

For Ear Training tools and drills, click here: The Ear Training Kit.

~Sean Shannon