My friend and I were talking about power requirements in loudspeaker design and the fact that almost all of the power is required to drive the woofers and move lots of air.
Then he asked “do basses exert more energy talking or singing than sopranos?”
Or put another way, does a lower frequency voice need more power (energy) to achieve the same volume as a high voice?
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:
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.