Mixing long hours can lead to poor mixing decisions, deception in perception, and worse – permanent ear damage. In this article, we look at how to protect your most valuable mixing tools – your ears – by understanding the symptoms and designing a healthy workflow.

Of all the technical skills an engineer can learn, mixing is by far the most challenging and oftentimes difficult. Seasoned professional mix engineers usually have learned how to deal with the issues of fatigue. They’ve created mixing workflows to enable them to weave the technical, creative and observational skills necessary to work quickly, efficiently and effectively. They have learned how to avoid the traps that cause mental and physical fatigue and become more sensitive to the symptoms of fatigue as they arise. Most importantly, they take appropriate measures before the fatigue sets in and causes the mix to spiral out of balance.

Even with the best artistic vision and technical skills at hand, mental and physical fatigue can destroy a mix in a short period of time. Most bad mix decisions and imbalances result from an engineer’s fatigue or lack of clear-headedness. So how can you avoid these traps and take on habits that help you to work better and more efficiently?

Manage Your Monitoring Levels

One of the quickest ways mixers can lose perspective on a mix is to listen at loud volumes over long periods of time. We all love the sound and feeling that comes from the thumping low end and added presence in the high frequencies, but if your mix doesn’t translate at a wide variety of listening volumes and speaker sizes, then only you get that experience.

Listening at loud volumes, in addition to causing fatigue of your hearing, also causes other physical acoustic issues. Depending on your system, pushing volumes can cause mechanical and acoustic compression of your mix. Overdriven amplifiers and speaker drivers lose accuracy and efficiency as they become more resistant to excessive gain. The high monitoring levels can also exaggerate acoustic resonances in your mixing space, causing you to wrongly compensate for them in the mix itself. What this can lead to is that when the mechanical driver compression and acoustic resonances go away, what you are left with is an unfocused mix that will not translate to lower listening volumes and smaller speakers.

This is a habit that can be hard to break, but it is an important one to manage. Since our hearing’s sensitivity to high and low frequencies within our hearing spectrum varies at different volumes, a good moderate listening level with a relatively flat response according to Fletcher-Munson Curves is about 85 dB SPL.

If you are not sure what 85 dB SPL sounds like in the real world, purchasing a sound pressure level meter or SPL app will be enlightening, but be aware that this magic figure of 85dB SPL is often taken out of context. Distance matters and the size of the room matters. This is why in film and TV mixing guidelines the size of the mixing space needs to be taken into consideration. Whereas 85dB SPL in a large cinematic mixing theatre is often used as a benchmark, by the time you come down to the room size we find in the average domestic home, we are looking at figures below 79dB SPL. It’s vitally important to educate yourself on what these numbers mean and how they affect the acoustics of your studio space. It will provide a great reference as you get used to managing your monitoring levels while you mix, and will help you to judge what you are listening to with some certainty.

Understand The Psychoacoustics Of Extended Critical Listening

One of the most frustrating elements of mixing is that our brain is always actively trying to balance our hearing with the environment we are listening in. It is constantly adapting to make what we hear intelligible. This means it’s increasing our sensitivity to higher frequencies when the music sounds dull and desensitizing them when the mix is bright or harsh. So the tendency will be to push more high frequencies as our senses dull; rinse and repeat this process over the course of a few hours and you can quickly see where this is going.

But wait, there’s more! Our brains also are more acutely aware of transient energy than sustaining energy. In other words, our brain is more focused on active changes in our environment, not static sameness. If you're not careful, this can make lower frequencies a victim, because they often consist mostly of sustaining energy. Higher frequencies generally account for more short-term bursts of energy that introduce new sounds and thus draw more focused attention. After some time getting used to a mix, this can make it easy to get used to low frequency 'mud' that only becomes apparent when listening back after a long break.

Worried yet? Understanding how our perception of sound works is vital to designing techniques that limit the brain’s ability to employ these effects. Good monitoring habits, in addition to limiting the effects of frequency masking, will also increase mental acuity and focus. They can help you to work more efficiently and effectively by exposing the problems in your mix more quickly. If you fail to find these problems early on, they can have a rippling effect on the way you approach sounds in the rest of the mix. Your mix can then quickly become a house of cards that falls when the problem is later discovered!

Design A Healthy Workflow

• Check your mix at different volumes. As a general rule, while mixing, keep your average listening level at a moderate volume that does not over-activate the acoustics of your listening space. However, it's important to change the listening volume every now and again and notice how the balances of the mix and the perception of sounds change, especially regarding the processing you've applied. Make the necessary changes that help it to be as even as possible at a variety of listening levels. 

• Use multiple monitors and headphones. If you have multiple monitors set up, switch between them regularly as you perform each processing task. This will quickly indicate if you have gone too far, or not far enough, with your processing. If you do not have a second pair of monitors, a good pair of headphones will act as a suitable alternative.

• Balancing low frequencies: In order to effectively monitor low frequencies in balance with the rest of the spectrum, Equal Loudness Contours (or as many people know them, Fletcher-Munson Curves) suggest that we need to raise the monitor level to at least 85 dB SPL. If you must work at these levels, try to keep the amount of time you spend at louder listening levels to a minimum. Turn up, make adjustments, lower the volume, change speakers, and raise the volume to check how your work translates. 

• Balancing high frequencies: Interestingly, our perception of low and sub frequencies is greatly enhanced by the balance of high-frequency content. In context, the challenge comes from the fact that most often, various changing instruments provide high-frequency content in a mix. When judging high frequency, monitor your adjustments in the context of the full mix and notice how it affects the low-end content. Check your adjustments at all volumes and monitor setups, and balance accordingly. 

• Balancing midrange frequencies: Midrange frequencies, from approximately 400 Hz to 6 kHz will translate to almost every monitoring setup, no matter how small. Most of our perception of localisation comes in this frequency range, and every instrument in a mix should be represented here, even basses. Low listening volumes are often best when making adjustments to the midrange as most speaker systems work very efficiently in this range. Change regularly to louder listening levels to check the relative balance to low and high frequencies. 

It’s vitally important to check your work at different listening levels and with different monitoring systems as much as you are able to. This will help to keep your physical hearing mechanism from adjusting too quickly to one listening situation and will keep your mental focus active. Remember, sameness is the enemy to efficient mixing!

In this video, mixer Chris Lord-Alge (Green Day, Bruce Springsteen) gives his tips on monitoring, including mixing at a consistent volume, but checking the mix as you go on a variety of playback systems, at a variety of levels:

Curb Mental Fatigue And Take A Break

Having trouble keeping your focus on the mix? You are not alone! Mixing can be a tedious process full of detailed processing and editing work that requires a lot of mental focus. In addition to the technical challenges, there is often a lot of stress around the mixing process, as it represents a final commitment to the song and production. Maintaining mental acuity is a vital part of maintaining your perspective and making quality decisions throughout the mix.

Mental focus is greatly affected by physical fatigue. Loud monitoring will tax our hearing mechanism and cause the brain to devote a lot of energy to protecting that system, and physical fatigue is one of the primary causes of mental fatigue – but not the only one.

• Limit distractions. You may be thinking, “Now they are going to tell me to turn off my social media feed when I mix!” The answer is, no, not necessarily. It largely depends on understanding what your own capabilities for attention are. If you are avoiding the mix as a result, then turn it off. If you turn to it as a way to give yourself a short break from intense mixing work, then it can be a good thing.

• Take a break! The most destructive mix habit ever is working relentlessly when you’re fatigued. The problem stems from a singular mix imbalance getting compounded into a lot of bad decisions. If you hear a problem in the mix, make an adjustment. If it doesn’t solve the problem, return it to the previous settings and try something different. If that doesn’t work, return the settings to where they were and take a short break. When you return, listen to the overall mix rather than what you were focused on. 9 times out of 10 you will hear the real problem right away and make the necessary correction. Try it, it works!

Balance Technical And Creative Work

Mixing is both highly creative as well as technical. Our right brain controls creative thinking and the left brain handles the technical processes. Alternating technical tasks with creative tasks in your mixing workflow can provide a break for the half of your brain that is not as activated. Here’s how you can break down technical and creative skills for mixing:

Technical Tasks

• Organising and colour coding

• Routing tracks to busses/stems

• Creating memory locations

• Balancing gain inconsistencies

• Editing out noise and blank regions

• Setting up effects returns

• Assigning plugins to tracks

• Basic pitch correction

• Removing plosives and sibilance

Creative Tasks

• Level balancing and setting pan positions

• Applying equalisation

• Applying compression

• Effects processing

• Applying automation

• Creative pitch shifting

The early part of a mix is often where most engineers focus on the technical work so that the mix can be properly prepared for the creative work. Some of this is necessary, such as track organisation and gain staging the audio files so that the creative process can flow smoothly. Many others such as colour coding, removing silence, and setting up effects returns are not necessary to begin the mix.

Rather than cramming all the technical work, in the beginning, set up the basic track organisation and routing and begin processing the tracks. As soon as you lose perspective on the mix, address some of the technical issues like creating memory locations, setting up effect returns or applying pitch correction. After a short while, you will get an idea of how to address some of the issues you’ve encountered on the creative or overall balancing side of things. At that point, stop the technical tasks and immediately resume the creative work until you lose perspective again.

This workflow switches between right brain and left brain activity, allowing you to stem the effects of mental fatigue by switching to tasks that utilise the less fatigued side. It will enable you to increase your efficiency and keep your undivided attention on the mix without burning out. This doesn’t mean that taking full breaks away from the mix won’t be necessary, but this way you will almost always take your breaks feeling that you have accomplished something of value during the time you have spent working.

In this video excerpt, mixer Michael Brauer (John Mayer, Coldplay) talks about his mixing workflow, specifically about working quickly on creative impulses so as to not get 'stuck' hearing the same thing for too long:

Mix Mindfully: Design Your workflow & Practice It!

Many experienced mix engineers will tell you that 80% of a mix gets accomplished within a couple of hours of work. The experience it takes to get there so quickly is as much about effective monitoring skills and managing mental fatigue as it is about sound processing techniques. Selecting the right processors and the right approach is only as effective as the engineer is clear and focused.

Remember, every person is different and has different capacities for the physical and mental skills necessary to create a great mix. What is most important, though, is that you are aware of your own capabilities and learn to adapt the techniques to support the skills that are weak, and enhance the skills that are strong. Fatigue is a given part of any sophisticated, and sometimes tedious process.

Your awareness of the effects of fatigue are a critical bridge to making the right decisions. Changing habits will take conscious attention at first, but will soon become a normal part of your workflow as you begin to reap the benefits in the quality of your work.

A Little History…

In the past, in the recording studio 'hit factory’ model, the producer and artist would often leave the mix engineer alone to work for hours before coming into the control room to listen. They would bring a fresh perspective, unencumbered by the physical and mental fatigue of listening to the same song for hours. Learning how to work effectively and efficiently for long hours was a necessity to accommodate the cost of studio time and hard deadlines to finish the project.

Today, many records are mixed in private studios unattended by the artist or producer. This leaves the responsibility of maintaining a fresh perspective all on the mix engineer. If you are serving the roles of artist, producer and mix engineer altogether, then learning the skills necessary to maintain your perspective and mix effectively is critical.

Do you have any tips that we missed? Let us know in the comments below.