Resonance: Beware the Myths and Pseudoscience

There’s a whole “healing” industry based on the terms “resonance,” “resonant frequencies,” “natural frequencies,” and “sympathetic vibrations.” But the usage of these terms is rarely scientific. The marketing has infected the dog world, with the plethora of sound and especially music products that promise to make our dogs feel good (or at least lie down). The marketing—and often the products—are based on pseudoscientific sleight-of-hand.

This post explains why the talk of resonant frequencies related to music—for dogs or humans—is nonsense.

The Science of Natural Frequencies and Resonance

Most of us have a general idea about resonance having to do with an object vibrating because of some external force. That’s a good start. But to really understand resonance, we need to understand natural frequency.

Natural Frequency

Natural frequency is defined as:

The frequency of the free oscillation of a system. — Law & Rennie, 2019

Natural frequencies exist in both mechanical and electrical systems. They are inherent physical attributes. When considering sound and vibration, we are discussing a subset of mechanical systems: acoustical systems. In this case, natural frequencies result from a relationship between a dimension of an object and the length of a corresponding sound wave. The oscillation involved is from sound waves or other mechanical vibration.

There are multiple natural frequencies of any object. If you strike a tubular bell with a wooden mallet, you will hear its natural frequencies, the most prominent one corresponding to its length.

For easily measured objects such as metal tubes or beams or even rooms (hollow boxes), it’s straightforward to compute the natural frequencies. I wrote a program to compute these frequencies for the enclosure we built as part of my graduate research (see page 45 and following in my thesis, on the topic of “modes”).

Resonance

OK, take a breath. Now, here’s a scientific description of resonance:

Resonance occurs when the frequency of the excitation force is equal to the natural frequency of the system. When this happens, the amplitude of vibration will increase without bound and is governed only by the amount of damping present in the system. — Seto, 1971, p. 4

An acoustics example in plainer English:

When an external sound of the same frequency as an object’s natural frequency is generated near that object, the object vibrates more than when sounds of other frequencies are played. This is resonance. Here’s a demo using tuning forks.

Here’s a different mechanical example involving not sound, but force applied to spring systems. The text explanation is solid, too.

You will also hear the term sympathetic vibration, which is close in meaning.

Summary and Comparison

Natural frequency is a frequency inherent to a system or object. Resonance happens when an external periodic force causes the object to vibrate at a natural frequency.

Damping

Here’s the reason that natural frequencies and resonance are not prominent in human (and dog) bodies.

For many objects, frequencies are highly damped. Damping is what it sounds like: the prevention of vibration. In general, it means that the vibration energy dissipates into a material. Following are examples of undamped and damped vibrations. But damping in the real world is not binary. It would be more accurate to discuss “less damped” and “more damped,” because nothing is completely undamped except in theory. But I’ll go with the binary terminology.

Undamped vibrations: Imagine our tubular bell again. If you struck it with a wooden mallet, you would hear a bell-like tone that would ring for a few seconds. It is resonating at its natural frequencies.

Damped vibrations: Now imagine a canvas sack of peanut butter suspended from a frame by a wire. It has resonant frequencies. You can add to your mental picture some rubber balls and wooden dowels of various lengths encased in the peanut butter to represent bones and organs, if you want. They also have natural frequencies. What would happen if you struck this canvas sack with the same wooden mallet? Thud, right? No pure tone, no duration. It would still vibrate at its natural frequencies, but the amplitude would be small, and duration would be short as the peanut butter absorbed the vibration.

We humans and dogs, with our bodies full of muscle, fat, orgnas, and fluids, are far more like that sack of peanut butter than we are like bells or gongs that vibrate extensively when excited. That’s the reality, and the most important physical factor when considering so-called resonance effects on our bodies. We don’t resonate well at all.

We understand damping from life experience. Which of these gongs can vibrate more freely? Which is considerably damped, and how is it damped?

Resonant Frequencies in Our Bodies

Our bodies, and parts of our bodies, do have resonant frequencies. My femur has a resonant frequency (Gautam & Rao, 2021). So do my skull (Fonville et al., 2022) and my lungs (Duarte & de Brito Pereira, 2006). My individual cells probably do, too (Puerto-Belda et al., 2024). But remember the peanut butter.

If I, a living person, am exposed to a pure tone that corresponds to one of the resonant frequencies of my tibia or kidney, am I going to experience a pleasant vibration in that bone or organ? Not likely. There is way too much damping. And even if I could feel the vibration, who is to say that it would be pleasant?

The human body as a whole has a resonant frequency. It’s generally between 3 and 7 Hz (Brownjohn & Zheng, 2001), although some researchers have found frequencies as high as 16 Hz (Randall et al., 1997). Sounds in those ranges are all below the threshold of human hearing.

What Is That Sweet Feeling, Then?

Some people enjoy the feeling of loud music and sounds vibrating in their bodies. When the movie Return of the Jedi came to theaters, I travelled to Cinema 1 in Corte Madera (north of San Francisco) with some musician buddies because that theater was said to have giant subwoofers. I wanted to hear and feel that jacked-up bass! The low-frequency rumbles of Jabba the Hutt and the inevitable explosions didn’t disappoint.

So what’s that feeling? It’s generally the palpable vibration from the external high-amplitude sound waves passing through our bodies. Sound waves are pressure waves, and we can feel the big ones ( those with low frequencies). The name of this type of vibration is forced vibration.

One more definition:

When external forces . . . are acting on the system during its vibratory motion, the resultant motion is called forced vibration. At forced vibration, the system will tend to vibrate at its own natural frequency as well as to follow the frequency of the excitation force. . . . In the presence of damping, that portion of motion not sustained by the sinusoidal excitation force will gradually die out. As a result, the system will vibrate at the frequency of the excitation force regardless of the initial conditions or the natural frequency of the system (italics mine). — Seto, 1971, p. 4

We have extensive damping in the human body. Hence, the above definition suggests that any natural frequency resonance will “die out” in the presence of forced vibration, e.g., loud, low-frequency sounds that jiggle our innards.

Forced vibration doesn’t have to come from sound. There are different “excitation forces.” If you’ve ever sat in a back massager chair, the excitation force is the vibration mechanism, and you are experiencing forced vibration.

I recently discovered a resonant frequency in my shower when I hummed. One pitch audibly popped out and made the whole enclosure vibrate pleasantly. I did some measurements and computations and the pitch corresponded to a natural frequency—of the shower. The highly reflective walls of the shower made for an intense sound field, and that was fun to experience.

I was not the one resonating; I was experiencing forced vibration. But don’t tell that to the “resonant frequency” pseudoscience purveyors. They want to convince you that the mathematical relationships between your body parts and sound waves makes you feel good. Oh yeah, and they’ll tell you it’s true for dogs, too.

Physics and acoustics textbooks define forced vibration and resonance in contrast to each other. In the real world, we will experience forced vibration much more often. It can range from pleasant to annoying to dangerous. The effects of different vibrations on human bodies are widely studied to prevent harm. Industrial settings and automobile design are two of the many settings in which potentially harmful forced vibrations are in play.

The Pseudoscience

It is widely believed that a resonant frequency from an external sound (or other waveform or “energy”) can be felt as a pleasant sensation: a buzzy-ness, warmth, or affinity in our bodies. Some say it’s more ethereal, a more spiritual energy. It’s supposed to feel really good. But this is not a scientific concept. It’s pseudoscience.

Here is some typical language about resonant frequencies. Joshua Leeds, the psychoacoustician affiliated with iCalm Pet (Through a Dog’s Ear), has this to say:

Everything has its resonant frequency—I think of it as a “resident,” or home, frequency—and we humans are no exception. That is why certain colors feel good to us and why we are attracted to certain instruments and sounds. The colors or sounds are within our resident frequency range and can make us vibrate from across the room. Our familiarity with their frequency has an effect on our mood.  — Leeds, 2010, p. 17

This is not the scientific definition of resonance or resonant frequency. Which is fine; it’s common for there to be more abstract or metaphorical versions of scientific terms in our language. We talk about the gravity of a situation or overcoming inertia. I have certainly said that a concept resonated with me when it felt true and right.

The problem is that people are led to believe that such language is scientifically based. In Dr. Leeds’ quote above, he is stating that mathematical relationships between our bodies and outside stimuli cause us to vibrate and feel good. That is vanishingly unlikely, especially with the examples he gave. For instance, the frequencies of the light spectrum that correspond to colors range from 400–790 THz. (That’s terahertz, where the “tera” prefix means 10¹², or one trillion.) I would ask Dr. Leeds:

• what part of my body has a natural frequency of, for example, 425,000,000,000,000 Hz;
• how I would feel this unimaginably fast vibration (faster than the human nervous system can capture, I’m pretty sure); and
• why that (physically impossible) feeling would make me “feel good” about a certain shade of red.

Irrelevant Topics

I know this is a funny heading. But these are topics that often come up in pseudoscientific discussions of resonance and frequency as points of argument

• Whole body vibration is used as a therapeutic technique for humans (Shantakumari & Ahmed, 2023). This is forced vibration, not resonance.
• Binaural tones are used to produce an internal oscillation phenomenon in the human brain that could numerically match an electrical frequency put out by the brain (e.g., alpha, beta, gamma waves). This is not the same as resonance, and there is no definative evidence that the practice is beneficial (Ingendoh et al., 2023).

Even if We Could Resonate, Music Is a Terrible Way to Go About It

Even if we could get our bodies or parts of them to resonate in response to an external sound source, music would be an ineffective way to go about it.

Trying for whole-body resonance is a non-starter. The tones that come out of speakers (even most subwoofers) do not go low enough. But let’s say I want to try to feel resonance in my tibia (bone) despite what I’ve learned about damping. So, do I put some loud music on my best speakers while wearing ear protection, focus my attention on my leg bones, and wait to see if I can feel my tibia resonate at some brief moment in the music?

I could narrow my music choices down a little. This paper (Christensen et al., 1982) concludes that the frequency of a tibia could be between 90 and 110 Hz. Those are low frequencies, but within the range of most types of music. I could make the occurrence of a frequency in that range more likely by picking a YouTube of a tuba concerto, a song by a Russian chorus, or a piece featuring Geoff Castelucci.

Even filtering my music choices to make lower frequencies more likely doesn’t mean they will have enough duration to have an effect. And remember, the target is one frequency. There are thousands of notes in pieces of music, and the combinations of frequencies change over time at fractions of a second.

If you want to try to trigger a resonant frequency in your own body part, not that I recommend it, you would best use a tone generator. Use a speaker system with a subwoofer, put on ear protection, and slowly scan through the frequencies, searching for one that makes some body part feel different. Note that you’ll feel more vibration with the lower frequencies; that’s from those big pressure waves. But if you actually hit a resonant frequency for a body part, you will likely never know. Remember the peanut butter. And don’t do this to your dog.

Please, please think about this when you read about the magic music for dogs that “helps” them via resonant frequencies. There’s no evidence for that.

Copyright 2026 Eileen Anderson

References

Brownjohn, J. M., & Zheng, X. (2001, June). Discussion of human resonant frequency. In Second international conference on experimental mechanics (Vol. 4317, pp. 469-474). SPIE.

Christensen, A. B., Tougaard, L., Dyrbye, C., & Vibe-Hansen, H. (1982). Resonance of the human tibia: method, reproducibility and effect of transection. Acta Orthopaedica Scandinavica, 53(6), 867-874.

Duarte, M. L. M., & de Brito Pereira, M. (2006). Vision influence on whole‐body human vibration comfort levels. Shock and Vibration, 13(4-5), 367-377.

Fonville, T. R., Scarola, S. J., Hammi, Y., Prabhu, R. K., & Horstemeyer, M. F. (2022). Resonant frequencies of a human brain, skull, and head. In Multiscale biomechanical modeling of the brain (pp. 239-254). Academic Press.

Gautam, D., & Rao, V. K. (2021). Nondestructive evaluation of mechanical properties of femur bone. Journal of Nondestructive Evaluation, 40(1), 22.

Ingendoh, R. M., Posny, E. S., & Heine, A. (2023). Binaural beats to entrain the brain? A systematic review of the effects of binaural beat stimulation on brain oscillatory activity, and the implications for psychological research and intervention. PloS one, 18(5), e0286023.

Law, J., & Rennie, R. (Eds.). (2019). A dictionary of physics (8th ed.). OUP Oxford.

Leeds, J. (2010). The power of sound: How to be healthy and productive using music and sound. Healing Arts Press.

Puerto-Belda, V., Ruz, J. J., Millá, C., Cano, Á., Yubero, M. L., García, S., … & Tamayo, J. (2024). Measuring vibrational modes in living human cells. PRX Life, 2(1), 013003.

Randall, J. M., Matthews, R. T., & Stiles, M. A. (1997). Resonant frequencies of standing humans. Ergonomics, 40(9), 879-886.

Seto, W. W. (1971). Schaum’s outline of theory and problems of acoustics. McGraw-Hill.

Shantakumari, N., & Ahmed, M. (2023). Whole body vibration therapy and cognitive functions: a systematic review. AIMS neuroscience, 10(2), 130.

Wagenaar, R. C., & Van Emmerik, R. E. A. (2000). Resonant frequencies of arms and legs identify different walking patterns. Journal of biomechanics, 33(7), 853-861. (I didn’t cite this study above; it’s just cool.)

Images

• The image of human body with lines of “energy” is from Rolffimages via iStock and involved no use of AI.
• The peanut butter graphic was created by me in Canva.
• The tibia illustration from Wikimedia Commons is used under this license and created by Anatomography.
• The two photos of gongs are from Wikimedia Commons. The one on the frame is used under this license and created by Ermell. The one propped against a backgrop is used under this license and created by Serg Childed. I cropped them both square.
• The image of Jabba the Hutt from Wikimedia Commons is used under this license and was created by Toby Philpott (the puppeteer).
• The photo of the tuba from Wikimedia Commons is used under this license and created by Buffet Crampon.