After deflating the assault boat on the beach and folding it away, Zhang Zi drove back to the pet store with peace of mind. There is no need to rush to return the underwater pickups to Professor Wei Kang for the time being, because I don't know if the recorded sound is complete. Although he didn't understand whale language, he knew that language was very complicated, and he couldn't learn it just by listening to a few bytes.

If Shihua said that the length of the recorded voice was not enough, then he would continue to repeat what he had done today until she was satisfied.

"Master, you're back, Godzilla...... No, did you record the voice you wanted to record?" Wang Qian ran over and picked up the battery, and asked inexplicable words in his mouth.

"Well, it's probably recorded, I'll edit it and make a copy of it later, you take it to Li Kun and let him play it as background music in the aquarium. Zhang Zi'an commanded, and at the same time carried a full set of underwater pickup equipment to the second floor.

Wang Qian said yes and returned to the store to charge the battery.

π had just finished writing a chapter and was stretching his waist back and forth in the living room, moving his body.

"π, I'll use the computer in a moment. ”

"Squeak. ”

Zhang Zi'an took out the memory card from the device, installed the supporting sound spectrum analysis software in the computer, and then imported the original audio files in the memory card.

The sound is converted into a waveform and output on the screen, but it is very disorganized, like a candlestick chart of a thousand stocks displayed at the same time, which is dazzling to watch.

He studied the use of the software, called the filter, filtered out all the high-frequency sounds, and the screen was immediately much cleaner, but there were still hundreds of curves left.

Next, he dragged the timeline further to find the position at the end of the audio file.

He roughly remembered when the whale's voice appeared, and by comparing the time of appearance and end, he further eliminated more than ninety percent of the noise, leaving a few curves.

Due to his lack of experience, the remaining curves could not be simply excluded with a sound diagram, so he simply used a clumsy method to select these curves one by one and play them.

Boom......

Click......

Click......

Bite......

Hiss......

A variety of sounds are heard from the laptop's weak speakers in turn, some of which are beyond the human ear and can only be heard by software.

Strange to say, he was already very focused, but when he heard these voices, it still felt strange, as if he had never heard them before.

"Squeak. ”

π scratched its ears and cheeks, as if it were itching all over its body, and it was obviously uncomfortable to hear some strange sounds, and finally it simply blocked its ears, jumped into the gondola wicker chair, and covered its head with a pillow.

Woo –

A familiar voice rang out.

Zhang Zi'an's heartbeat suddenly accelerated.

That's what I heard! Like a train whistle, the sound periodically increases and decreases, occasionally mixed with the sound of a train wheel rolling over a rail junction.

Finally found it, he held down the left mouse button and did not dare to let go, for fear that after releasing this curve would be overwhelmed by other curves, but dragged it to create a new window alone.

In the new window, the curve resembles a periodic uplift of the mountain, steep on one side and gentle on the other, with several undulating peaks, which are the sharpest part of the whistle and often correspond to the clattering sound at the top.

In the coordinate axis where the curve is located, the X axis represents the time and the Y axis represents the frequency of the sound.

He shifted his gaze to the Y-axis.

"Huh?"

He froze.

There are only a handful of whales that have grown to such a large size, and if you exclude the right whale with tumors and toothed whales like sperm whales, there are not many options left.

Zhang Zi'an thought that the giant whale was a blue whale or a fin whale, but the number mark on the Y-axis indicates that he guessed completely wrong.

The frequency band of the blue whale sound is basically between 15 Hz and 40 Hz, mainly concentrated in the range of 15 to 20 Hz, in recent years, due to the excessive noise created by humans in the ocean, there is evidence that the sound frequency of the blue whale is gradually shifting to low frequencies, getting closer and closer to 15 Hz, in order to avoid conflict with human noise.

The fin whale's sound frequency band is narrower, between 15 and 25 Hz, mainly around 20 Hz.

The hearing range of the human ear is 20 to 20,000 hertz, and without the help of instruments, humans can hardly hear the sounds of blue whales and fin whales0.

However, the frequency band range corresponding to the Y axis on the screen is between 45 and 50 Hz, which is directly audible to the human ear.

Strange, is there something wrong? This curve is not the voice curve of the giant whale?

Some whales have a wide range of sound bands that cover this range, but those don't grow up to be so large.

Zhang Zi'an thought about it for a while, and the most normal and reasonable explanation was that when he recorded the giant whale, there was another whale of a different species lurking in the nearby sea. He thought it was a giant whale's voice, but it was actually another whale's voice.

But is there such a coincidence?

If that's the case, then where did the whale's voice curve go?

He switched back to the original window and played the remaining curves one by one again, much to his dismay, unable to determine if the sounds were made by whales.

It would be nice if there was a veteran submarine sonar here, and he would be able to tell him what the things that made those sounds were.

He was a little depressed, he thought that he would finish the battle, but now it seems that he will go to record a trip tomorrow, hoping that he will not be mistaken next time......

Wait, is it really a mistake?

He tries not to miss every possibility.

What if I'm not mistaken? What if the sound recorded tomorrow is still this abnormal sound curve?

It can't always be a mysterious whale that never shows its face, right?

There is an ultimate method of elimination called "Occam's Law", which in the simplest words is, "Do not add substance if you don't have to."

The road is simpler, and the simpler the better.

Specifically, when two hypotheses have exactly the same explanatory and predictive power, we will use the simpler hypothesis as the basis for the discussion.

Zhang Zi'an became alert and realized that he was making a mistake, adding an entity out of thin air in order to explain the anomaly - another whale that followed behind the giant whale and mysteriously never showed his face.

Is it really necessary to increase this entity?

In fact, there is another explanation that can achieve the same effect - the voice of the giant whale is like this, and there is no other mysterious whale.

Which of the two explanations is simpler? Obviously, the latter.

The razor of Occam flashed with cold light, slicing the former to pieces.