Giant bug noises

Question

I understand, vaguely, how human voices vary with the overall size/shape of the individual(s vocal chords), and I can use that to make reasonable assumptions about what the voice of non-human fantasy race of oversized (giants), or undersized (gnomes, fairies, etc.) humanoid race might sound like compared to a 'standard' human voice.

But I do not know enough about the noises bugs make for me to be able to confidently make similar assumptions about how their communication noises might change when the animal is scaled to a fantasy sized variety.

What differences would be expected in the noises made by bugs, if they were scaled up to giant versions of themselves?

Details, specifics, limitations, etc. :

1. how/why do these giant bugs exist? Handwavium, they just do. These are not an evolution from real species to fantasy species, they are not a fictional species independent of existing animals, they are the actual existing species just bigger. Ignore any issues caused by the square/cube law thing, except maybe to handwavium increase structural integrity of body parts to support new size, no new materials allowed, no new structural organization of parts and materials, they just are strong enough to be bigger because handwave.

2. "Noises" = sounds produced by the bug, and only the bug, for the purpose of communication. This can include mating calls, noises to try to scare away predators, noises to cooperatively hunt or other social needs, etc. Incidental noises, such as buzzing of wings during flight, or footsteps (or multiple legs contacting each other) as they walk, rubbing against objects in their surrounding environment, etc. don't count. If the bug uses other objects from the environment to produce the sound (such as a wolf spider vibrating leaves) that doesn't count either.

3. "Bug" = Insect, Spider, Scorpion, or Centipede, unless you can make a very convincing argument for something else that might be called a "bug" by a layman. Some specific examples of the type of thing I'm referring to are cricket chirps (probably the most obvious and recognizable bug noise of all), hissing-cockroach hiss, "barking" or "Whistling" spider (Selenocosmia crassipes) hiss, Flag tail centipede (Alipes grandidieri?, others?) hiss.

4. "Giant version" = Let's say approximately the height/length/girth/weight of a large breed of dog, like a St. Bernard. EDIT: Think ": Honey I Shrink the Kids" technology, not evolution or alien physiology, but rather the exact identical real-life animals just scaled up completely, proportionately, and in every aspect. Obviously, many "bugs" are not the same proportionate shape as a dog, so modify as needed within the spirit of the question, exact measurements shouldn't create enough of a difference in the answer to nitpick unnecessarily. In other words, I don't feel like (for the purposes of this question) there would be a significant difference in the sound made by an 6 foot long centipede compared to a 10 foot long one, regardless of whichever of the two might be closer to 'dog-sized' by weight or width or whatever, as long as we don't get out of hand and start discussing what it would sound like if it were as tall as a car and longer than 2 buses. Use best judgement, common sense, reason, when trying to apply 'dog-size' to something that is not 'dog-shape'. Other than size, nothing else about the animal should change, or should change as little as possible to accommodate any complications that might otherwise arise from the added size (no mammalian lungs/vocal chords or any similarly radical change, only increased size of whatever they used before to make their noises originally, and as little structural change in those as possible to support the additional weight/volume/etc.).

5. "differences" in the noises = Pitch and Volume are the two most obvious here. Would the sound have the same pitch, but just be louder, or vice versa? Or would the pitch change so much, that it becomes separate intermittent clicks or impacts, rather than a tone or pitch at all? Would Duration change while pitch and/or volume stay the same? Would the sonic texture change, from seemingly one sound source to multiple sources?

For those of you who didn't know, and/or don't believe, that spiders make such noises, here's an example(WARNING to those who are creeped out by such things, it's creepy)

Answer 1

As @AlexP mentioned, and according to the wikipedia page he linked to, bugs usually rub body parts together to make a noise, so your giant bugs would probably use the same system.

As a general rule, the bigger the object, the lower the sound frequency.

Therefore, you could imagine similar noises to real world bugs but lower. A cricket's chirping could sound more like an ominous thrumming, or an ant's squeaky stridulations could be so low than your average human might confuse them for mechanical parts, like a tire/wheel.

A question you have to ask yourself, is how different are your giant bugs to real world bugs, and which parts of them are going to be giant? For example, the wiki article states that spiders emit their "hissing" stridulation by rubbing their leg bristles together. Would a giant spider also have giant leg bristles? Would each leg have the same size bristles? Would its mandibles have smaller bristels, allowing for a greater control of the emitted stridulation?

Maybe your giant bugs evolved more complex stridulatory organs to allow for better communication with other animals. As long as you're in handwavium territory, that's a fairly easy concept to handwave into existence imo.

Answer 2

What Whitehot said about generally louder volumes and lower frequencies seems right. Think about string instruments: As you move from violin to viola to cello to bass, the pitch of the instrument drops in proportion to the size of the instrument (due in this case to the hollow resonating chamber and the length and thickness of the strings). Any change in pitch really depends on what kind of organ is creating the sound, though, and I'm not totally sure whether crickets, for example, would sound much different. Some insects' noisemaking organs are more percussive, while others are more like vibrating strings. But as a general rule, lower frequencies do seem likely. As do longer-sustained notes. Lower frequencies, I believe, don't lose their energy as quickly as higher frequencies (please correct me if I'm wrong). To use the string instrument analogy again, if you hit a low note on a piano, it resounds much longer than a high note because the string is longer and the note is lower. Same thing with basses versus violins, or tympani drums versus snare drums. But many noisemaking insects can already sustain their calls for a really long time. It has more to do with how the insect sustains its calls by repeating them with continuous stridulations or other methods.

Beyond that, here are some factoids that might inspire you. First, don't forget about katydids and cicadas!

Unlike crickets, cicadas make their rattling noises by rubbing their wings together. They also have a special noise-making organ called a tymbal, whose ribs buckle one after the other when the cicada flexes its muscles. Every time a rib buckles, the tymbal clicks. It's also important to note that cicadas make their calls during the day, while crickets and katydids call at dusk and at night.

Katydids, meanwhile, produce a variety of sounds (including a loud ticking sound and a synchronized rattling) and can even imitate the calls of other insects. They stridulate using a plectrum (like a guitar pick) which they scrape across a file or comb on their forewings. Katydids (or leafhoppers) are also obviously cool because they evolved to look like bright green leaves, and thus have excellent camouflage.

Here's another interesting detail about katydids from SongsOfInsects.com: "Males within each group synchronize their songs while the two groups alternate their songs, thus creating a resounding pulsation of sound that can overwhelm the listener."