The Tympanic Reflex: Science + Application
Let’s take a basic tour of the anatomy of the inner ear.
The basic signal flow in the inner ear is as follows: A sound enters through the ear canal. Fun fact—I recently learned that the general resonant frequency of our ear canal is around 3 kHz. The sound then strikes the tympanic membrane (eardrum), which transmits the impulses to the three smallest bones in the body: the malleus, incus, and stapes. These bones then nudge the cochlea, a small organ in our inner ear. The cochlea delivers the impulses to fine hair cells called cilia, which somehow translate mechanical impulses into electrical impulses—it’s like the body’s natural I/O or DA-AD, but instead of converting voltages to digital(01), it converts mechanical energy to voltages(electrical).
These electrical impulses are sent to the brainstem and then to the brain, though I won’t go into that here. Suffice it to say the sound is then heard. There are two tiny muscles in the inner ear: the tensor tympani and the stapedius. When exposed to volumes between 70 and 90 dB, these muscles flex and engage the tympanic reflex.
Now, notice I didn’t say 70-90 dB SPL or 70-90 dB FS; I just said dB because what we are referring to here is 70-90 dB HL (hearing level). There is a lot of math involved in converting HL to SPL, but suffice it to say, for now, that they are relatively linear (not exactly, but relatively). HL just accounts for how the human ear perceives loudness at various frequencies rather than pure sound pressure measurements.
If you’re still with me, this is about to get really interesting. When the 70-90 dB threshold is crossed and the tympanic reflex engages, it dulls or attenuates our sense of loudness as a protective mechanism to prevent overloading the cochlea. Essentially, it acts as a natural compressor. The tympanic reflex takes 50-100ms to fully engage and about 100-200ms to fully release. Once that threshold is crossed, after about 50-200ms, we are no longer perceiving the full loudness of the sound at an SPL level. This is incredibly important when we are trying to be perceived as LOUD.
I’m glossing over a lot of science because I’m not a scientist—I’m a producer—but I’m starting to understand the anatomy behind this, and it’s blowing my mind. I’m glossing over the differences between hearing level and SPL. Furthermore, the tympanic reflex has different responses at different frequencies and when exposed to different stimuli. However, I’m presenting this information to build upon it in the future.
I truly believe this is cutting-edge information that we are just beginning to understand. In my initial video, I mentioned that I’ve heard a lot of producers talk about “checkerboard” and “layer cake” style mixes (which I’ll explain in a second). I’ve also heard a lot of audiologists and auditory scientist discuss the tympanic reflex and its frequency responses, but I’ve never heard many people connect the two so in as far as how it relates to Music Production itself. Let’s go deeper.
What conclusion can we draw from this information? Well, I’ve coined the term “The Law of Loudness.” You won’t find this phrase on Google; it’s just my own conclusion. It states:
More dynamic sound is perceived as louder than less dynamic sound when played at equal average loudness.
In other words, a more dynamic sound—one with a larger ratio of loud to soft—is perceived as louder than less dynamic music, which has a smaller ratio between loud and soft sounds, even when played at equal average volume. [pause for dramatic effect……………….]
If that doesn’t blow your mind, revisit what I just said. It’s counterintuitive to the common assumption that more sound equals more loudness. In reality, it’s a ratio relationship between loud and soft. If you look at a traditional metal song, it appears visually as a solid waveform with very little dynamics. In contrast, a traditional classical song is highly dynamic. You might assume that if both are played back-to-back at equal average volume, the metal track would sound louder. But that’s not always the case.
Another way to illustrate this: If you take a drummer on stage with an average volume of -3 dB SPL and compare them to the full band with the same average volume, the drummer is perceived as louder. Why? Because the tympanic reflex is constantly engaged more often in a band dynamic, allowing the listener to perceive more dynamics from a drummer thus being perceived as louder.
So, what does this mean for audio creation? If we can find small, tiny, incremental and clever ways to introduce sub-tympanic threshold sounds (soft sounds or silence) in micro-moments within a track, it will do a few things:
Expand perceived dynamics.
Engage the tympanic reflex in a way that enhances loudness perception.
Minimize listener fatigue by giving the ear muscles brief moments of rest.
Now, a caveat: This primarily applies to modern genres where loudness is a key factor—hip-hop, trap, rock, metal, EDM. If you’re concerned with maximizing loudness in your productions, understanding and implementing these strategies is essential. This isn’t about mixing or mastering necessarily—it’s about production itself.
So, how do we skillfully insert dynamics into styles of music that are historically low in dynamics? There are two primary ways I do this: One way is what I call The Dynamic Slam – Using volume utilities on primary sub/instrument busses to introduce volume automations on eighth notes, quarter notes, or finer time divisions(i.e on vital instr. like drums/guitars/bass all at once). Instead of applying volume changes across an entire master/mixbus, strategically placing these on select sounds for tiny durations (e.g., 500 ms, a 16th note, a 32nd note). This creates a more intelligent and engaging effect
Another method I use is what I call Raw Dog Aux Tracks – parallel audio tracks outside the main mix that allow certain elements (like vocals or small effects) to momentarily pop through the mix while everything else gets slammed off on the main/master/mixbus.
If you’ve ever had music bumping in your earbuds and then suddenly stop all at once, you might feel a low rumble or pressure for a split second—that’s the tympanic reflex disengaging. I even believe there may be a pleasure factor involved in this process of consciously and actively “yolking” this reflex on and off(kinda like sex;)
Some producers, like Mr. Bill and Gates, describe this as “checkerboard” production, as opposed to “layer cake” production, where everything is stacked on top of itself with minimal dynamics. By strategically introducing micro-moments of silence, the listener actually perceives more loudness.
The importance of this can’t be overstated. This knowledge can deeply influence not only production but also mixing, mastering, and the overall sculpting of sonics. It’s not a button or a plugin; it’s an approach to sculpting sound consciously.
So, what do you think? Have you experienced the tympanic reflex in your listening? Do you enjoy when producers use this technique? I believe this is the future of music production, and I’d love to hear more discussions about it. Drop a comment below and send me examples of music where you think this concept is being used. Our own bodies are the best testing ground for this phenomenon.
If you’re interested in having your music professionally produced, drop me a line at the email below. Much love. See you soon!
