Actually, higher frequency sounds require MORE energy than lower ones at the same volume (amplitude) - so sopranos technically use more energy than basses when singing at the same perceived loudness, but our vocal anatomy is optimzed for different frequency ranges so the practical energy expenditure depends more on individual vocal efficiency than pitch alone.
this post was submitted on 21 Jul 2025
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Disclaimer: I am not an audio engineer or musician, I have a college-level understanding of physics, and I dick around with video games and electronics as a hobby, so I have a little specialized understanding of audio, waves, energy, etc.
Human voices don't work like loudspeakers where the diaphragm vibrates. Our diaphragm moves air through constant pressure, and the larynx is what actually creates the vibration. A deep vs high-pitched voice is defined by the geometry in the larynx. It's more like a breath-operated instrument like brass or woodwinds, and in those, the difference between high and low notes isn't all that significant.
It might be more significant between a bass and alto saxophone, but the sheer volume of the instrument itself plays a greater role. And usually they're played louder than a typical singer.
I don't know if there is actual measurement of energy expenditure for human vocalization. You could measure energy of the sound waves, but I'm not sure if that would directly correlate in the way you're thinking.
Edit: as mentioned I'm no engineer, so if the larynx uses any kind of resonance to produce its sound, I have no idea how that works.
total peanut gallery but when people talk about instruments that take a ton of breath to play it does seem to be the lower note ones like tuba. I don't even play instruments this mainly comes from friends who played complaints.
Tuba and flute take the most breath to play. You have to move air FAST through a flute, while a brass instrument is more about the vibration of your lips than sheer air going through.
ok yeah and now that I think of it flute was up there and its not known for low.
Uhh, for a standard wave, higher frequency means more energy at the same RMS amplitude. Might it just be that humans are less sensitive to bass notes (and so need louder speakers)?
People with louder voices would definitely expend more, at least, although I'm guessing the human voicebox is inefficient enough in the first place it wouldn't be significant.
It's a function of amplitude AND frequency.
I would argue that these things are hella complicated to accurately say due to the complexity and inefficiency of biology. for example, a lot more power might be required than is present in the output wave, because of losses in the process of sound formation.
Well, for bass frequencies you have to move more air to get the same SPL. It makes sense that would require more energy. Flip side is that the tuning of your voice makes specific frequencies much more efficient to reproduce. Think of that like your singing range. Once you leave your natural range, some notes get way harder to sing. It's all about what notes are easiest and most efficient.
Volume is based on amplitude while frequency determines pitch.
Keeping frequency the same increasing amplitude is higher energy.
Keeping amplitude the same increasing frequency is higher energy.
So at the same volume(amplitude) a higher pitch(frequency) takes more energy.
The reason woofers have to move so much air is to increase amplitude of low frequency sounds. Humans generally perceive lower frequency as quieter, if a low and high pitch are at the same amplitude the higher pitch will be perceived as louder despite equal measurable volume due to audiological perception.
So does this question basically boil down to the following?
For a constant "perceived loudness", what does the plot of energy vs. frequency look like?
Once we know what the plot looks like, we could simply compare the bass and soprano regions.
I wondered about that at first, but then realized something: A good speaker has a flat frequency response, i.e. for a given input signal, it measures the same from bass to treble, against a 0dB reference. Does that correspond to power output, or...?
The simple physics above assumes perfect transition of energy to a given soundwave.
A flat frequency response is more of the real world engineering/acoustics regarding a speaker. It measures frequency and amplitude(dB) of input to output. Where the ideal is a 1:1 transition of input to output. Whether that actually corresponds to the power draw of a given speaker is an engineering question. Physics without engineering considerations still follows the previous where higher frequency is higher energy at same amplitude.
If you think about it a tweeter at 15,000Hz is moving back and forth 15,000 times in 1s. A woofer at 40Hz is only moving 40 times in 1s. While each woofer movement is more air it is slow while the tweeter is less air but much faster. As to why more air for the woofer that delves into how soundwaves are generated and propagated. A longer wave needs more space to not be cut short.
OK then let me ask this: Why do bass notes (and more to the point, woofers) require so much more power for a given volume? Is it just the increased moving mass of the speaker and air?
If that's the case, then I suspect that @SheeEttin@lemmy.zip has got the right answer:
Human voices don’t work like loudspeakers where the diaphragm vibrates. Our diaphragm moves air through constant pressure, and the larynx is what actually creates the vibration.
But I'm not sure. Yet.
To go into human voices more the vocal folds within the larynx are the primary method of human pitch control. Air moving over the vocal folds vibrates them resulting in sound. Control of vocal fold tightness or loosening by associated muscle is how we alter our pitch. Generally male vocal folds are longer, for lower pitch, while female vocal folds are shorter, for higher pitch (post-puberty hormones). Males also have larger lung capacity than females generally.
The main method of altering loudness is by forcing more air through the vocal folds, creating a larger amplitude vibration.
Diaphragms are not pushing air at constant pressure unless you're holding a note.
As I noted earlier bass is perceived as quieter at same amplitude due to how our ears are shaped and work, however, bass also travels farther it is able to be heard farther away with less dissipation because longer waves are less likely to "run into" other stuff.
The nose, pharynx, and mouth also act as resonators and articulation that further alter human sound.
For the engineering yeah it is probably just about moving more air, and more air has to be moved because it is a longer wave that needs to be created.
Read that as "bosses" and started thinking about the TV show. 🤦🏻♂️
I have no idea what the scientific answer is, but try to see how long you can sustain a really low note in your own voice before you run out of air. Then see how long you can sustain a really high note before you run out of air.
That's measuring airflow required, which is not equivalent to energy required.