Rylenne's Shrinking Research Part 1 - Can tinies be heard by normal sized people?

I do a lot of research for stories, to make sure my details are realistic, accurate, and immersive, and recently I have been doing even more to go even further. To me, a story is a lot more erotic if it has realistic details, when I am reading a story, it's better if I know this is what would really happen in that scenario. So todays topic is: After shrinking, can tinies be heard by us normal sized people? How small is too small to be heard? In this report, I use real math and science, so these research reports will give you an idea of what it would actually be like to be tiny! Parts 1 - 3 are more like a prologue, that go over some interesting questions, and the interactive story/Choose your own adventure, begins in Part 4! Parts 1 - 3 are written from the perspective of Rylenne Duck, the main character of Mad Shy Science. Enjoy!

I often have this dream, where someone is shrunk down to a centimeter/ten millimeters tall, and I have been wondering, at that size, could they still be heard after I shrink them? After doing my research and some experiments on some totally willing tinies, I found that If someone were shrunk down to one centimeter tall, hearing them speak would be extremely difficult, if not impossible, without some form of amplification, like a teeny microphone nearby them. I found I would need to either keep them in a small container with a microphone, or make one small enough to attach to them, which is difficult when they are that small.

At that new size, one cm, their vocal cords would be proportionally tiny—about 100 times smaller than a normal human’s. The volume and pitch of their voice depend on the size and vibration of those vocal cords. Smaller cords vibrate faster, producing a much higher-pitched sound, likely in the ultrasonic range (above 20,000 Hz), which is beyond human hearing (typically 20 Hz to 20,000 Hz). Even if some sound fell within us normal sized people's audible range, the amplitude—essentially the loudness—would be drastically reduced because their tiny lungs couldn’t push enough air to create significant sound waves.

it's like a mosquito’s buzz: it’s audible because it’s amplified by rapid wing movement, but a centimeter sized tiny wouldn’t have that advantage. Their speech might register as a faint, high-pitched squeak at best ( and to be honest, that’s assuming they could even breathe and vocalize effectively at that scale, which is doubtful due to physiological limits like surface tension and air viscosity, but all of that has to be ignored when making these stories. At most sizes, you would not realistically survive long due to the fact that you might not even be able to breath, but in my stories, upon shrinking your lungs can hold in more air, and you overall gain more survival talents, like how a cockroach can survive a nuclear blast)

But yea, without a microphone, trying to hear my new centimeter sized tiny would be like trying to hear a whisper from across a football field, but only worse. So how much would I need to grow them to hear them again? What is the smallest size that a tiny can still be heard? This is where things get a bit more complicated as we get into some math!

To figure out the smallest size at which a tiny could still be heard by a normal human ear without amplification, we need to consider the physics of sound production and human hearing. The key factors are the volume (loudness) and frequency (pitch) of their voice, which depend on the size of their vocal cords, lung capacity, and ability to push air.

So lets consider some facts about hearing, and vocal chords -

• Vocal cords: In humans, vocal cord length ranges from about 1-2 cm (10-20 mm). Sound loudness scales with the amount of air moved, which is tied to lung volume (proportional to body volume, or length cubed, L³). Frequency, meanwhile, scales inversely with vocal cord length (1/L)—smaller cords vibrate faster, producing higher pitch.

• Hearing threshold: The human ear can detect sounds as quiet as 0 dB (10⁻¹² watts/m²) at around 1-4 kHz, where we’re most sensitive. Frequencies above 20 kHz (ultrasound) or below 20 Hz (infrasound) are inaudible, and very quiet sounds get drowned out by ambient noise (typically 30-40 dB in a quiet room).

As someone shrinks, their lung volume drops dramatically (L³), reducing the energy available to produce sound. Their vocal cord length (L) also shrinks, raising the pitch. At 1 cm tall (a 1/170 scale for an average 170 cm human), their vocal cords would be about 0.06-0.12 mm long, producing frequencies around 25-50 kHz—ultrasonic and inaudible. Plus, their tiny lungs (about 1/5,000,000th of normal volume) couldn’t generate enough sound pressure to be detectable at any distance.

To be heard, their voice needs to stay within the audible frequency range (20 Hz to 20 kHz) and produce enough volume to reach at least 0 dB at your ear, say, from a foot away (30 cm). Studies of small animals like mice (5-10 cm long) offer a clue: their vocalizations start around 5-10 kHz and can drop into human-audible ranges (e.g., 4-5 kHz for distress calls), but these are still faint unless amplified or very close.

Now lets consider some other factors:

• Frequency limit: If we assume a normal human voice has a fundamental frequency of 100-200 Hz, shrinking to 1/10th size (17 cm tall) raises it to 1,000-2,000 Hz—still audible. At 1/20th size (8.5 cm, or 85 mm), it’s 2,000-4,000 Hz, also audible and near peak human sensitivity.

• Volume limit: Loudness scales with L³. A normal speaking voice (~60 dB at 1 meter) would drop to ~20 dB at 1/10th size and near 0 dB at 1/20th size, assuming no ambient noise. In a quiet room (30 dB background), 1/10th size might be the practical limit for faint audibility at close range.

So with all that in mind, the smallest size a tiny could be and still be heard is likely around 8-10 cm tall, because:

• Their vocal cords (0.5-1 mm) produce a high-pitched voice (2-4 kHz), still audible to humans.

• Their lung volume (1/5,000th of normal) generates just enough sound pressure to be detectable in ideal conditions (very close, no noise). Below this—say, 5 cm or smaller—the pitch climbs too high (5-10 kHz and beyond), and the volume drops too low to hear without help. So, 8-10 cm is the rough cutoff where physics still allows a whisper to squeak through.

Now that my serum is much more reliable, stable, and relatively safe, I feel like the serum and I are ready for something more.. fulfilling. I have just been having to rely on my tiny clones to do these studies, which is not as fun.. No matter what I try, a lot of the clones are either extremely boring, or complain too much. Some have too many of my memories, I've tried to limit their access to them, that way it's easier for them to come to terms with their purpose, but it always goes pretty poorly. I do not want to study something that is pitching a fit every five seconds. But what if.. what if I found someone willing, who would want to shrink? Now that I think about it, I might know of a place to look for some. I know it's rare, but theres actually some kind of shrinking fetish out there that people have, they would be thrilled for a opportunity like this, if I can find some trustworthy people, some that fit the perfect criteria, maybe that could work..