4 psychoacoustics tricks to enhance your mix

Whether you’re new to producing music or have some years of experience under your belt, the world of audio engineering continues to reveal fascinating techniques and concepts that can help you craft music that not only sounds great but also connects with your audience on a deeper level. One concept worth exploring is psychoacoustics – the science of how our brains perceive sound. In this article, we’ll delve into four essential psychoacoustic techniques – Sound Localisation, Equal Loudness, the Missing Fundamental, and the Shepherd Tone- and how you can integrate them into your own projects. Before we get started though let’s take a moment to understand exactly what psychoacoustics is.

Author: Alex Sajjadi (picture)

What is Psychoacoustics?

In short, Psychoacoustics is the study of how our brains perceive sound and in turn respond to it. When it comes to music production, understanding psychoacoustics can be a game changer because it allows you to influence the way in which listeners will perceive your music. This is because our brains are incredibly sensitive to various aspects of sound, such as pitch, loudness, and spatial location. By harnessing these aspects, you can create music that immerses your listeners and makes your tracks stand out.

Now let’s explore four essential psychoacoustic techniques that will transform your music production.

psychoacoustics 1 – Sound localisation

Sound localisation refers to the brains ability to determine the source of a sound. That is to say, the direction and distance from which a particular sound has originated. This is achieved by our brains ability to differentiate level, time, and frequency between each ear. As with a number of psychoacoustic properties, this most likely stems from an evolutionary advantage to help us survive in the wild. Today however it usually helps us pinpoint the location of a car horn or an airplane in the sky. In music production, simulating sound localisation can not only add depth and immersion to your tracks, but make them sound more live and organic.

Take a moment to familiarise yourself with an audio example. Listen to how panning, reverb & delay adds depth and space to the drums.

How to utilise Sound Localisation

Sound localisation can be utilised by modifying the panning and delay of an instrument. All digital audio workstations such as FL Studio, Logic or Ableton provide you with a range of panning and reverb options for each track.

• Panning: Experiment with panning your instruments slightly to the left or right to mimic the spatial positioning of real-world sound sources. This will go to create a more immersive listening experience.
• Reverb & Delay: Use reverb and delay effects to simulate distance and space. Increase the pre delay to increase the perceived space the instrument is in. Pair this with a touch of reverb to make an instrument sound like its in a large hall. Decrease the pre delay and reverb to simulate a smaller space.
• EQ: For an extra touch, apply a high cut to your delayed and reverbed signal to simulate the loss of frequencies due to the absorption of sound.

psychoacoustics 2 – Equal Loudness:

Equal Loudness contours, also known as Fletcher-Munson curves, deal with how our ears perceive different frequencies at various levels. That is to say, the human ear doesn’t hear all frequencies at the same level when played at the same volume. This is most noticeable when listening to music at low levels. At higher levels, frequencies begin to sound more equal to one another. In general however, our ears are most sensitive to frequencies ranging from 2-5kHz, due to the fact our voices are most audible within this range. When it comes to making music, this phenomenon is crucial to understand for balanced mixing.

Listen to the example below, I’ve created a series of sine tones, each an octave higher than the last. Notice how the volume doesn’t change but each subsequent tone seems to get louder. You can use the graph below to determine what frequency each tone relates to.

 

Image: Fletcher-Munson-Curve Equal Loudness Contour.
Source: Read more about the Equal Loudness Contour at Produce Like a Pro

 

How to utilise Equal Loudness

• Equalisation: Use an EQ on individual tracks to account for the differences in perceived loudness between frequencies. Boosting or attenuating specific frequency ranges will help to achieve a more balanced mix.
• Monitoring Levels: Pay attention to your monitoring levels. If you mix at extremely low or high volumes, you might misjudge the balance of frequencies. Keep your monitor levels within a reasonable listening range for the most accurate representation. You can always increase the level temporarily to check the low-end of your mix.

psychoacoustics 3 – The Missing Fundamental:

The missing Fundamental, is a fascinating psychoacoustic phenomenon that refers to the brains ability to perceive a fundamental tone, even when it’s absent from the sound. This can be highly effective in making your productions sound fuller. You can reinforce the tone of an instrument while making sure it doesn’t interfere with your mix. Utilising this phenomenon is also extremely important in helping your songs translate more consistently onto smaller speakers, which, let’s face it, most people will listen to your music on.

Check out the link below for an audio example. The first few seconds of the clip contain the fundamental tone; from that point on, however, it’s been removed. Notice how the texture or timbre of the sound changes, but the note remains the same.

How to utilise the Missing Fundamental:

• Bass Emphasis: Use an EQ or Compressor to boost the harmonic content in your bass. This can make it sound fuller and more powerful, even if the fundamental frequency isn’t as prominent.
• Layering synths: Layer multiple synths to reinforce their harmonic content. This can help make them stand out and give them more energy in your mix.
• Saturation & Distortion: By adding saturation and/or distortion you will reinforce the harmonics present in the sound boosting it and making the fundamental more audible.

psychoacoustics 4 – The Shepherd Tone:

The Shepherd Tone is an auditory illusion that creates the sensation of an ever-rising or falling pitch, even though the actual pitch remains constant. Famously utilised by Hans Zimmer in scores such as the Dark knight and Dunkirk, this effect can add tension and excitement to your music when used creatively.

Below you can find an example of a Shepherd Tone I made myself, as well as one used in one of my favourite tracks. See if you can figure out which element of the song has been turned into a Shepherd Tone.

How to utilise the Shepherd Tone:

Here’s a step-by-step approach that I’d like to share with you

• Creating a Shepherd Tone starts by creating a continuous tone with a synthesiser or sample.

• Make sure it can loop continuously.
• Now duplicate the tone twice, raising the pitch of one duplicate by an octave and the other down by an octave.

• You’ll now have three continuous tones separated by 1 octave each.
• Automate the pitch of all three tones to increase by an octave over the duration of the sample.

• Automate the level of the higher tone to decrease along the duration of the sample.
• Automate the level of the lower tone to increase along the duration of the sample.

• Apply a crossfade should your Shepherd Tone not loop properly.
• You should now have a Shepherd Tone!

Conclusion:

Incorporating Psychoacoustic techniques into your music production can elevate you tracks and make them sound more unique. From creating immersive spatial experiences with sound localisation to achieving balanced mixes with Equal Loudness, these techniques offer endless possibilities.

Experiment with these psychoacoustic concepts, and don’t be afraid to push the boundaries of your creativity. As you explore and refine these techniques, you’ll discover unique ways to captivate your audience and create music that leaves a lasting impression.

The only limit is your imagination.

About the author

Written by: Alex Sajjadi. Alex is an Amsterdam-based Audio Engineer & Music Producer working under the pseudonym Miniatour. He is a graduate of Abbey Road Institute Amsterdam. Learn more about Alex and Miniatour.

Graphics: Dennis Beentjes

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