Mix Bus: 6 Ways To Clean Up Mix Mud

Does your mix sound like mush? You’ll know it when you hear it, because the tonal balance of your song will sound tubby. Instruments will be blurred together rather than distinct, and they’ll sound distant and muffled. Here are six ways to reduce muddiness so your mixes can emerge with clarity
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Cakewalk Sonar's Sonitus:fx EQ is creating a slight cut around 300Hz and a gentle rolloff starting at around 80Hz, both of
which can help reduce muddiness.


Leakage (signal bleed) in a multiplemic situation is a major cause of muddy sound. Examples of leakage are the drum sound picked up by a scratch-vocal mic, or the electricguitar sound picked up by an acoustic-guitar mic. I explained several ways to reduce leakage in the June 2008 issue of EQ: place mics closer, overdub instruments, record direct, gate the toms, deaden room acoustics, omit the bass amp, and impose high-pass filters on most instruments. It also helps to position bass traps in your studio and control room to suck up boomy low end.


Too much reverb can muddy the mix. For some reason, many recordists assume a song sounds more “produced” if it’s bathed in reverb and/or echo. But if your mix is sounding muddy, mute or disable all effects for a moment. Does the mix suddenly become clearer? If so, turn down the effects send levels. You might be surprised how little reverb you can get away with. I also recommend putting no reverb on the bass and kick drum, using shorter reverb times (especially if the song’s tempo is fast), and trying echo instead of reverb (just be sure to reduce feedback so you get fewer repeating echoes, and adjust the delay time so the echoes don’t mess with the groove). Another trick is adding about 50ms to 100ms of pre-delay in your reverb unit or plug-in so that the listener hears the direct sound of the instrument for a short time before the reverb kicks in. This can clarify the sound by separating the reverb from the direct sound, as well as help the reverb appear more audible so you can use less of it.


As discovered by audio researchers Fletcher and Munson, we hear less lows and highs (around 4kHz) when monitoring at low volumes rather than high volumes. For example, a rock band might sound bright and punchy when you hear it playing live at around 110dB. But when you record the band, and play back the track without EQ at a normal listening level of approximately 85dB, it can sound dull or muffled. Compensate by boosting EQ levels in the highs and/or upper mids.


If the sound is bloated or tubby, try cutting 1dB to 2dB around 300Hz. This seems to be a “magic frequency” where a lot of mud resides. It’s also common to cut between 400Hz and 600Hz on toms and kick drums. In addition, recording several background vocals can result in bass buildup, so turn down the lows in massed harmonies. If the mix sounds kind of “heavy,” or too strong in the deep bass, use a high-pass filter on each track. Starting with a low corner frequency, slowly turn up the frequency until the sound thins out, and then back off a bit.


Sometimes, a mix sounds muddy or dark because it’s weak in the high frequencies. Try using EQs to boost the presence of instruments that lack clarity, apply an audio enhancer (but watch for added noise), and make high-frequency boosts after you compress, as compression tends to reduce the perceived impact of tonal tweaks.


A clean mix is uncluttered—meaning that too many parts are not playing at once. Arrange the music so that similar parts don’t overlap. Mix selectively so that not too many instruments are heard at the same time. For example, you might bring in vocal harmonies only during the choruses, or have guitar licks fill in the holes between vocal phrases, rather than playing on top of the vocals (think “call and response”).

In a clear-sounding mix, instruments do not “crowd” or mask each other’s sound. They are separate and distinct. Clarity arises when instruments occupy different areas of the frequency spectrum. For example, the bass provides lows, keyboards emphasize mid-bass, lead guitar punches out upper mids, and cymbals fill in highs. Often, the rhythm guitar occupies the same frequency range as the piano, so they tend to mask each other’s sound. You can aid clarity by equalizing them differently. Boost the guitar at, say, 3kHz, but cut the piano at that frequency. In other words, use complementary EQ. If the bass and kick drum blur together, thin out the kick and add lows to the bass, or vice versa. Use a high-pass filter or turn down the lows on some tracks— especially guitars—to leave room for the bass guitar and kick drum. The guitars might sound thin when soloed, but the overall mix should sound balanced. It also helps to pan similarsounding instruments to opposite sides. For example, the rhythm guitar and keyboards might cover the same frequency range, but you can make them more distinct by panning the guitar hard left, and the keys hard right.