the sound of insects

Oto-kun

Earlier, when you talked about "which side of the brain you hear sounds with", you mentioned that you would talk more about the sounds of insects, right?

father

Ah, it's about how Japanese people listen to the sounds of insects and nature with the language-processing left hemisphere of their brain.

Oto-kun

Is the sound of insects just noise to people from other countries?

father

Indeed, it seems that people in America and Europe do not particularly feel a sense of seasonality from the sounds of insects. I heard a story before that when a film was jointly produced by Japan and America, and the footage shot in Japan was sent to America, there was a complaint that it contained noise and they wanted it reshot. However, upon investigation, it turned out that it wasn't noise, but rather the sound of cicadas recorded outdoors in summer. For Japanese people, the sound of cicadas is a seasonal characteristic of summer, so it wouldn't feel out of place as background noise, but for Americans, it probably just sounded like noise.

Oto-kun

I wonder if there are cicadas in America.

father

It seems that, depending on the region, there isn't a loud chorus of sounds during the summer in Japan. I've also heard this story: a long time ago, when Ueno Zoo bought elephants from Germany, a German zookeeper stayed for about two months for training. When that German was returning to his country, he was asked by Ueno Zoo what they could give him as a thank you, and he said, "I want that singing tree."

Oto-kun

Are you referring to the tree where the cicadas were chirping?

father

That's right. I didn't think it was the sound of cicadas.

Oto-kun

Last year, I read 'Sound of the Mountain' by Yasunari Kawabata in Japanese class. The teacher said that it is difficult to explain the beginning part, 'It is ten days before August, but the insects are chirping,' to foreigners.

father

My father has heard that story too. The translation by the American Japanologist Seidensticker is 'Though August had only begun, autumn insects were already singing.' However, the situation of insects singing and its relation to the sense of the season is not grasped, so the meaning is not understood.

father

There is an interesting case of analyzing insect sounds. This is the sound of crickets and bell crickets, but first, listen. Can you tell which is which?

Oto-kun

The suzumushi chirps 'rin rin'. The first time I heard it, the sound was so beautiful that I wondered, is this the suzumushi? (Insect sound 1)

father

Correct! Indeed, the sound of the bell cricket is perceived as more beautiful. Analyzing these two sounds yielded interesting results. First, when comparing them using 1/3 octave band analysis, there is almost no difference, as shown in Figure 1.

Oto-kun

But, I certainly thought that the sounds were similar in pitch.

father

That's right. Both have dominant sounds at 4 kHz and 5 kHz. Next, when we create a map using the variational sound analysis that we used for the shamisen and naki-ryu sound analysis before, it turns out that they are very similar as well. (Figure 2)

Oto-kun

Is it true that even with sound analysis, the difference in how crickets and bell crickets sound is not detectable?

father

Dad also thought at first that it was strange. The sensation I heard felt like the sound of crickets was rough, so I thought there would be a difference when subjected to fluctuation sound analysis. Just like before, when I analyzed the roughness of the sounds of the singing dragon and the shamisen, which were described as murky and rough. But this was simply a matter of the scale of the axes on the map. There is no doubt that both are fluctuating over time at the same frequency/fluctuation frequency, but the magnitude of the fluctuations is different. The diagram (Figure 3) that shows the adjusted axis scale reveals that the magnitude of the fluctuations in crickets is numerically about 15 times that of bell crickets.

father

Insects like crickets have a sound-producing part called the stridulatory organ. On the wing veins, which are branched veins on the wings, there are fine serrated projections, and by rubbing these wing veins together with their limbs at high speed, they produce sound.

Oto-kun

It's interesting that when you extract the components that vary over time, the differences between the sounds of an instrument like the shamisen, insect sounds, and the sounds created by a space resembling a crying dragon become clear, not just in terms of pitch and volume.

father

That's right. In the case of friction sounds generated during the operation of various machines, the frequency and fluctuating frequency are related to the sound generation mechanism, making this important information for addressing noise and abnormal sounds, as well as for sound creation.