8 Reasons For Muffled Mixes & How To Fix Them

If you've spent any amount of time mixing, you've likely encountered mixes that demand extra work so as not to sound muffled. On the other hand, perhaps you're employing techniques that contribute to muffled mixes and want to learn what those detrimental habits are and how to break them. Either way, you've come to the right place! I had these issues at one point and can teach you how I go about un-muffling a mix in this article.

Let's get into each of these reasons in greater detail throughout this article and investigate a few strategies to fix each issue. Before we get started, though, let's consider how we can tell whether our mix is muffled or not.

---

How To Tell If Your Mix Is Muffled

Meriam-Webster defines muffled as:

• a: to wrap or pad with something to dull the sound
• b: to deaden the sound of

Regarding sound and acoustics, high-frequencies naturally lose energy faster than low-frequencies as the longitudinal sound waves travel through media (solids, liquids and gases).

So then, when something is muffled, like our mix, we'll have a deadening of the overall sound that affects the higher frequencies more than the lower frequencies.

A muffled mix, therefore, will sound lacking in the upper midrange and high end.

But that's not all. Muffling a sound also dampens its transients and dynamics, meaning there's less variation between the loudest and quietest parts of a muffled sound relative to an equal unmuffled sound.

We can naturally tell whether a mix sounds muffled simply by listening to it. However, the extent to which a mix is muffled can be more difficult to determine, especially with ear fatigue, loudness bias, and other psychoacoustic trickery.

It's important to have proper monitoring that gives us an accurate representation of the mix. This means monitors and headphones with flat frequency responses and maybe even a subwoofer to cover the low end. It also means proper room acoustic and acoustic treatment when monitoring through studio monitors.

If we can't hear our mix accurately, we'll have a more difficult time finding and addressing issues of muffledness and more.

Another important tool for understanding issues of muffling in our mixes is the use of reference mixes.

A reference mix (or reference track) is an audio mix/track that we can compare our work against as we make our way through the mixing process. A reference track is typically in the same style/genre as what we're working on and acts as a goal post to work toward in terms of mix aesthetic.

By A/Bing our mix against a reference, we can get quick feedback as to whether our mix is brighter or darker. If we've chosen a reference mix that's decently bright and our mix is very dark in comparison, we'll likely have to make some adjustments to reduce muffling and increase the overall brightness.

I have a video going into detail regarding reference mixes. Check it out here:

Of course, this is all assuming you have healthy hearing, especially in the highest octave between 10 and 20 kHz. If everything sounds muffled to you, then perhaps it's time to visit an audiologist to get your hearing checked out.

But for everyone else, let's get to the reasons why mixes may sound muffled and what to do about them.

---

Lack Of High-End Frequencies

The most obvious cause of muffled-sounding mixes is a lack of energy in the high-end, so let's get this one out of the way first.

Beginning with an example, try speaking aloud and continue speaking as you cover your mouth with your hand. By covering your mouth, your hand is blocking and absorbing a lot of the high-end frequency content of your voice, causing your voice to sound muffled.

Extend this to mixes, and it's easy to conceptualize that a lack of high-end frequencies will lead to dark, muffled results.

How To Fix A Lack Of High-End Frequencies

Beyond rearranging the song to add brighter elements or re-recording those tracks that are duller than they should be, there are strategies to bring up the high-frequency content of a mix.

The first is to increase the gain/volume of tracks with strong high-end content. If we already have tracks with high-frequency content, we may want to start by simply budging their faders upward.

If doing so makes the tracks' lower frequencies too prominent in the mix, we can opt to cut some of the lower frequencies with EQ.

Alternatively, the next is to use high-shelf boots in our EQ. These filters increase the gain of all frequencies above a set corner/cutoff frequency. We could also use bell filter boosts for less broad results, though high-shelving is often best if we really need to fix muffling.

Now, we could opt to insert a high-shelf boost on the mix bus itself to bring up the overall high end of the mix. However, it's generally advised to boost those individual tracks (or instrument subgroups/buses) that would most benefit from added top-end rather than the entire mix itself.

That way, we can make space for the tracks that most deserve the extra brilliance in an effort to reduce the muffledness of the mix.

But the brilliance range (about 8 kHz and above) isn't the only range that may lead to lacklustre results when under-represented in a mix. We can also opt to boost frequencies below that, even with the typical bell-curve-type EQ, to bring up the presence of certain instruments if they're overly muffled.

Bringing up the presence in the 4-7 kHz range can help bring out certain elements in the mix and lessen the “muffle” of the mix. I find this particularly useful on guitars (both acoustic and electric) and also with vocals, especially if they aren't cutting through the mix as they should.

Harmonic saturation enhances the harmonics of an audio signal and even produces new harmonic content in many cases. These harmonics can have the effect of brightening a sound and reducing the overall muffledness of the mix.

The aural excitement process effectively combines harmonic saturation with a high-pass filter so that only the highest frequencies of the added harmonic content are added to the mix.

In some more experimental cases, we can try pitch-shifting to add upper frequencies to the mix. If you're trying out this production technique, I'd advise setting up a parallel return channel and running the pitch shifting through the auxiliary track/return to have independent control over the original and the pitch-shifted version. I'd also recommend using octaves rather than other intervals to maintain the truest integrity of the original.

---

Build-Up Of Low And/Or Midrange Frequencies

On the other side of ‘lacking high-end energy' is having too much low-end or even low-midrange energy.

The low-end plays an important role in nearly all mixes and should be well-represented. However, it's also critical that we do not over-emphasize these frequencies.

For one, these low-end frequencies demand more power to be heard by us humans. While our natural hearing response is universally accepted to be 20 Hz – 20,000 Hz, we're naturally less sensitive to the longer wavelengths of low-end frequencies.

This can be visualized in the following Fletcher-Munson curves and Equal loudness contours:

So, it can be tempting to increase the gain/volume of low-end elements to hear them in the mix. However, going too far will cause these power-hungry frequencies to quickly eat up our headroom and tilt the overall frequency content in a way that muffles the mix.

Similarly, low-midrange frequencies can cause problems in muffling the mix. Although we generally refer to build-ups in the range of 200-500 Hz as “muddy” rather than “muffled,” it's still important to have good clarity in this range to achieve decent separation between elements in the mix.

How To Fix Build-Ups Of Low And/Or Midrange Frequencies

If you're able to re-record or rearrange the song so that the bass instruments have audible fundamental frequencies, this simple step can make a big difference in the presence of the low-end, the amount of headroom available, and ultimately, the clarity of the entire audible spectrum.

This generally isn't an issue with instruments like bass guitar, tuba, kick drum, timpani, etc. However, it can easily be the case that a sample or a synthesizer is playing too low to be adequately heard in the mix.

For example, a sine wave bass line playing in the 20-40 Hz octave will be difficult to mix audibly. If we were to bring that synth bass line up an octave to 40-80 Hz, we'd have an easier time hearing it in the mix, meaning we'd need less gain/volume and/or distortion. This, in turn, will open more headroom for the midrange and high-end frequencies to shine through.

The first actual mixing strategy to reduce the build-up of low-end and low-mid frequencies in the mix, and therefore reduce the effect of muffling, is to simply turn down the gain or volume of these bass elements.

Of course, we should still be able to hear them, but having them too loud in the mix will be detrimental to the overall darkness-brightness of the mix.

Note that we'll perceive the bass frequencies more clearly as we turn up our monitoring (see the Fletcher-Munson curves and Equal loudness contours above). It may very well be that the bass frequencies nearly disappear at low listening levels, and that's sometimes okay.

Another way to reduce the build-up of low and low-mid energy, specifically, is to use subtractive EQ. Cutting these frequencies, even gently, from those instruments that take up space in the low end of the mix can help reduce the clutter in the low end and offer more space to the midrange and high-end frequencies.

Speaking of eliminating clutter in the low-end, high-pass filters are invaluable tools in mixing for this very reason.

It can be worthwhile to high-pass nearly every track in the mix that doesn't have musical content. This way, we can make room for elements with musical content in the low end.

Reducing low-end energy to help solidify and strengthen the sub-bass and bass ranges of the mix may seem counter-intuitive, but the frequency masking between all the tracks with low-end energy will lead to worsened definition.

I have a YouTube video dedicated to frequency masking. Check it out here:

By clearing up the low end, we'll have greater consistency (thanks to fewer phase issues) and benefit from not having to boost the important low-end elements as high in the mix.

Returning to harmonic saturation, we can apply saturation to bass elements to help enhance their midrange content. In doing so, we can make them more present in the midrange frequencies, where our ears are the most sensitive, and ultimately increase the perceived loudness of the bass elements without necessarily increasing the low-end content of the mix.

We're much less likely to overdo boosting the low end if we can hear the bass elements in the midrange.

Another strategy to help us avoid boosting low-end elements is to utilize sidechain compression to allow the low end of the kick to poke through the mix. By sidechaining the kick to the bass element(s), the bass element(s) will be quickly ducked whenever the kick is present in the mix. This way, we can stabilize the low end and help everything be heard.

I have a video dedicated to using sidechain compression in the mix. Check it out below:

---

Poor EQ Choices

Poor EQ choices can lead to a plethora of issues in the mix. The over-misuse of EQ often leads to thin mixes if we cut too much and cause too many phase issues. However, it can also lead to muffled mixes if we aren't careful which frequency bands we're cutting and boosting in the overall mix.

As previously mentioned, it's likely not the best strategy to simply boost the low-end elements of a mix. Rather, it's often best to increase their presence in the midrange for them to be heard more clearly.

It's also not always wise to cut too much from the upper-midrange and high-end frequency bands.

Furthermore, boosting too many tracks in the low-mids will cause muddiness and, if taken too far, even muffledness in the mix.

How To Fix/Avoid Poor EQ Choices

Avoiding poor EQ choices begins with developing a strong sense of the purpose of EQ, which ultimately stems from the purpose of mixing: to achieve a proper balance between the tracks of the session.

In terms of the balance of levels, faders are our primary tools. EQ, in a way, can be thought of as frequency-dependent fader control. In fact, graphic EQs are just that.

In understanding this basic concept, we can better utilize EQ to achieve balance and avoid creating dark, muffled mixes.

Another critical strategy for better EQ decisions is to EQ in the context of the mix rather than EQing tracks individually in solo. The mix is rarely about any single track but rather about how all the tracks work together.

However, when it comes to EQing each track in the context of the mix, things can get a bit tricky. I will usually start with a specific group of tracks (all the drum tracks, for example) or, alternatively, with the mix's most “important” tracks.

I advise putting together a hierarchy of mix elements, listing every track in order of importance or “presence” in the mix. Then it'll be easier to know which track to give preferential EQ treatment, especially when significant frequency masking arises.

And, as always, I'd advise to always A/B test any EQ moves by toggling the EQ on and off. If the EQ benefits the mix, move on. If it doesn't, try adjusting the parameters so that it does. If that doesn't work, perhaps EQ isn't right for the mix, and there will be other ways to reduce the muffledness of the mix.

I have a video where I share my top 11 equalization techniques. Check it out here:

---

Overly Competitive Arrangement

An overly competitive arrangement will lead to a dense mix. If too many tracks compete for the low-end and low-mids, it can be tempting to try to “shoehorn” everything in, which can often lead to a muffled or muddy mix.

The truth is that there's only so much sonic real estate in any mix, and overcrowded arrangements, especially when there are a lot of tracks with significant information below 400 Hz, will typically lead to lacklustre results if not addressed.

How To Fix An Overly Competitive Arrangement

The first and most obvious way of reducing the competition in the arrangement is to rearrange the song. Of course, this isn't always something that can be done. The song was written and arranged that way for a reason.

That being said, we can also choose to mute certain tracks that are contributing to the muffledness of the mix. This could be the case with tripled or quadrupled tracks, particularly when these tracks have significant energy, again, in the low end.

Muting auxiliary instruments may or may not help a muffled mix sound clearer, though it may be worth experimenting with.

It's sometimes the case that muting certain tracks at specific sections can help with the arrangement, though it's important to do any muting tastefully. If it doesn't help reduce the muffling of the mix, it may be best to leave everything intact, even in dense arrangements.

Suppose we can't do too much about the density of the arrangement. In that case, there are other tools to help us improve the separation between the elements, giving each track its space in the mix and, hopefully, creating a clear, unmuffled mix in the process. Some of these tools include:

• Balancing: adjusting the relative levels of the tracks.
• Mirrored EQ: boosting certain tracks at important frequency bands while cutting those bands from other tracks.
• Sidechain compression: using the audio from one track to control the gain reduction of a compressor acting on another track/tracks.
• Panning: moving tracks to different parts of the stereo panorama (from left to right).

Finally, as a similar point to muting specific sections of tracks, we can also automate any of the above processes to help clarify and brighten the mix throughout the song.

---

Overcompression

Overcompression, as the name suggests, happens when a compressor acts too aggressively on a signal and effectively squashes the dynamics.

Audio without defined dynamics sounds pretty lifeless. On top of that, overcompression can add a significant amount of distortion to the signal.

Muffled sound is partly a relative reduction in higher frequencies, but it's also a reduction in transients and dynamics. Therefore, overcompression has the potential to severely damage the audio and cause muffling in the mix.

How To Fix/Avoid Overcompression

Fixing overcompression in a mix is similar to fixing bad EQ in the mix in that it requires a fundamental understanding of the basic role of compression.

To reiterate the purpose of mixing, mixing is about achieving a proper balance between the tracks of the session.

In terms of the balance of levels, faders are our primary tools. Compression, in a way, can be thought of as automatic fader control: as the audio surpasses a set threshold, the compressor automatically reduces the output level.

In understanding this basic concept, we can better utilize compression to achieve balance and avoid creating dark, muffled mixes.

Once again, like EQ, another critical strategy for avoiding over-compression is to compress tracks in the context of the mix rather than in solo. The mix is rarely about any single track but rather about how all the tracks work together. Refer to your hierarchy of elements for guidance.

But with that said, a great way to avoid overcompression is to utilize a top-down approach, where we begin compressing at the mix bus (top), work our way down to the subgroups/buses, and finally to the individual track if need be.

By compressing the larger buses (being fed by multiple tracks), we can get the “glue” compression, helping bring elements together in the mix while also controlling dynamics. In avoiding compressing every single track, we can avoid the pitfall of overcompressing in serial at each stage/bus a track's audio will pass through.

As with any processing during mixing, it's important to A/B test our compression moves by toggling our compressors on and off to hear whether they actually help the mix or not.

If we find ourselves in a situation where the audio has been overcompressed and then printed (the effect is now part of the audio file), then we might be able to restore transients with a transient shaper or an expander.

Unfortunately, it's unlikely that we'll even get anywhere near the original clarity of the signal with these efforts. However, it's worth trying them in a bind.

I have a video where I share my top 11 compression techniques. Check it out here:

---

Too Much Limiting

Brickwall limiting (the more common type of limiting in modern mixing) works on the same principle as compression, though at a ratio of ∞:1. In other words, a limiter is designed to not let an audio signal level past a hard set threshold.

Limiting is incredibly useful for maximizing loudness without clipping the mix/master bus. It's also a good tool for controlling the dynamics of tracks and buses before the mix/master bus.

That said, like compression but worse, over-limiting can suck the life out of music and cause muffling, especially if the high-end energy is already lacking energy before the mix is limited.

How To Fix/Avoid Too Much Limiting

Avoiding over-limiting is similar to avoiding overcompression. Be sure to A/B your choices, and don't drive the limiter too hard.

When A/B testing, it's paramount that level matching is done appropriately (having the same perceived level whether the limiter is on or off). We naturally have a “loudness bias” that all too often convinces us that louder is better, even if it isn't.

Beyond that, gaining an extra dB of loudness is sometimes worth it for competing in the loudness wars. However, gaining a bit of extra loudness at the expense of muffled clarity is never worth it, in my opinion.

---

Too Much Distortion

Although we've discussed how harmonic saturation/distortion can help improve the overall frequency content of a mix to reduce muffling, distortion can also have the opposite effect if pushed too far.

Distortion has the effect of reducing the clarity and definition of sounds when pushed too hard. If there's too much distortion in the mix, we may lose the sense of clear transients and produce a somewhat muffled mix.

How To Fix/Avoid Too Much Distortion

The first strategy for avoiding too much distortion in the mix is to ensure adequate headroom so that we aren't overloading and clipping any analog or (especially) digital equipment. This is true on the way in (recording) and during mixing.

It's important to gain stage when recording and mixing to help avoid overloading and clipping.

I discuss gain staging and how to do it in this video:

Perhaps the most obvious point to avoid too much distortion is to dial back the distortion-type effects you're using (if applicable). This includes saturation, which can get pretty rad when pushed too far.

As I stated in the last two reasons for muffled mixes, overcompressing and over-limiting will also cause distortion and a dulling of the mix, so they should, again, be avoided if possible.

---

Over-Represented Time-Based Effects

Overdoing time-based effects like delay and reverb can quickly wash out a mix, causing poor definition of tone and transients in the individual elements. While these effects may not have a huge impact on the overall darkness or brightness of the mix, they certainly can at higher levels. Even at lower levels, they can muffle the transients of the mix.

So, pushing delay and reverb effects too hard can contribute to a muffled mix.

How To Fix Over-Represented Time-Based Effects

The first strategy I have for you in regard to time-based effects is to nearly always set them up on their own effects return channels. Send individual tracks to an auxiliary track and have the reverb or delay inserted on that auxiliary track rather than directly on the individual tracks themselves.

By utilizing auxiliary returns, we can have much more independent control over these time-based effects, which is nearly always a great thing.

One big advantage of doing so is that we have independent fader control for each effect return channel. Therefore, if we're muffling a mix by washing it out with reverb or delay, we can simply turn the reverb or delay channel down.

Another strategy is to reduce the time of the time-based effect to make it more concise and less washy. This would mean the delay time and feedback/repeats parameters for delay effects and reverb time and size parameters for reverb effects.

Furthermore, we can EQ the effects to fit them better into the mix and to help reduce clutter in the low end. We can also compress them to push them a bit further in the mix if that will help bring the dry tracks out a bit more in the mix and avoid muffling.

Related Questions

Why does my mix sound thin, and how can I fix it? Thin-sounding mixes often suffer from thin arrangements or poor recording, to begin with. However, bad EQ choices, phase issues, overly wide stereo images, or a lack of low-end energy, compression, distortion or time-based effects can also cause a thin mix. Finding and addressing each of these issues can solve the issue of thinness in a mix.

Why does my mix sound distorted, and how can I fix it? Distorted recordings often cause distorted mixes. However, distortion can also arise at the mix stage, where digital clipping (exceeding 0 dBFS), the over-representation of harsh high-end frequencies, overcompression, over-limiting, and, of course, distortion effects, can also cause the mix to distort and sound distorted. Address these issues to reduce distortion in your mix.