"Xiaobai, I'm here to visit the door!" Zhao Xingsheng carried a large bag of various snacks and followed Xia Cong into Gu Xiaobai's laboratory.

Gu Xiaobai's laboratory is open, so I have to celebrate.

When he entered the door, he saw two bald professors inside, typing in front of the computer, seemingly doing word work.

Gu Xiaobai was sitting in his room, reading a book.

Zhao Xingsheng walked in with snacks, took a closer look, and found that Gu Xiaobai was reading a few books on electromagnetism, and he was still writing and painting next to it.

"Aren't you engaged in acoustics? Why are you still studying electromagnetism?" Zhao Xingsheng wondered.

"Oh...... Acoustics and electromagnetism are actually interconnected. Gu Xiaobai said.

Zhao Xingsheng: "?????"

I'm a liberal arts student, I don't read much, don't lie to me.

Gu Xiaobai was writing and drawing next to him, not knowing what formula he was deriving, or what he was calculating, and explained to Zhao Xingsheng:

In fact, the two can be calculated by the same formula, in the 70s of the 19th century, the German physicist Helmholtz obtained an equation from the wave equation of electromagnetic waves after separating the variables, ∇2A+k2A=0......"

I don't understand.

Vaguely, Zhao Xingsheng felt the fear of being dominated by Gu Xiaobai's flute formula last time.

He wanted to run away now.

The ∇2 in this equation is what we usually call the Laplace operator, where A is the wave mode shape (or natural mode shape) and k is the frequency (or natural frequency) corresponding to this mode shape. ”

What? We don't usually talk like that, right? Isn't Laplace a Pokemon?

"This equation applies not only to electromagnetic waves, but also to thin film vibrations, and even string vibrations, because strings are one-dimensional, thin films are two-dimensional, and electromagnetic waves are three-dimensional, and they are all vibrating and follow the same law. ”

I guess I got it.

It turns out that everything in this world is the same.

"For general vibration problems, the shape and mass distribution of the object are given to find the natural mode shape and frequency of the object, and this kind of problem is called a positive problem. ”

"Now we can also do the other way around, if we know the natural mode shape and frequency of an object, we can know its shape in reverse......"

"The way the film vibrates, unlike string vibrations, can be seen as superimposed sine waves, and its mode shapes are very complex, and this mode shape affects the timbre of a drum. ”

"Then you can put some heavy objects on the drum surface to suppress a certain vibration of it, and you can make the drum sound better......"

This Zhao Xingsheng still understands, tune the drums!

Moreover, it is the same drum, some people beat it out well, and some people beat it out badly, because of this.

Depending on the position and dynamics of the blow, the timbre will be different.

Tone control is always the most important and difficult technique.

However, modern people do not often use this method, and modern people usually develop more suitable materials, or control the thickness of the material itself to suppress some undesirable waveforms.

But the words of the ancients would have been unable to do this.

"So you're reducing your workload by calculating?" Zhao Xingsheng understood.

"So to speak. Gu Xiaobai said.

"Then consider the problem of the material itself, the skin used in the drum is the skin of the Chinese alligator, the Chinese alligator belongs to the genus of alligators, that is, alligators, there is only one kind of alligator in China, that is, the alligator, but it is illegal to use the skin of the Chinese alligator, we can only retreat to the second, using the belly skin of the American alligator to make the drum. The American alligator is larger than the Chinese alligator, so choose a young alligator. (Note 1)

"In addition, among the ruins, a large number of bone plates of the dragon were found, that is to say, the ancients were very rough and shallow on the Yangtze crocodile skin, and there were a large number of bone plate remains, which are not as soft as the modern crocodile skin, so the edge of the dragon drum actually has a certain thickness and hardness, and the middle abdomen is not dense, and the skin is relatively soft without ossification, so the drum should be a situation between the plate vibration and the membrane vibration, the outer ring plate vibrates, and the inner ring is more similar to the membrane vibration ......"

"The combination of two different vibrations gives it a very peculiar tone, which is not quite the same as the sound of other drums. (Note 2)

Zhao Xingsheng nodded again and again when he heard this, and it sounded that what Gu Xiaobai said was very reasonable.

"Okay, Xiaobai, you guys have made a name for themselves so quickly!" Zhao Xingsheng exclaimed.

Sure enough, even if Gu Xiaobai didn't win the project this time, this valuable experience, as well as the process of verification and knowledge, is also a very valuable asset.

The teacher must be very happy to see Xiaobai make such progress again.

At this moment, another door opened, and Qin Chuan poked his head out from inside: "Xiaobai, you can come and tune!"

Tuning?

What the heck?

"This is coming!" Gu Xiaobai entered another room and saw that Qin Chuan, Senior Sister Jing and 306's four single dogs were all there.

Gu Xiaobai didn't have too many people to use, so his friends came to help.

There were also various tools inside, as well as two hollowed-out tree trunks.

A crocodile skin cut into a round shape is covered in a hollowed-out tree trunk.

"Where did the crocodile skin come from?" Zhao Xingsheng glared.

Crocodile skin is known as the gold in the skin, especially these crocodile skins, all of which are back open skins, and there are almost no flaws in the abdomen, which can really be said to be more expensive than gold, more than 100,000 a piece, and there are at least seven or eight pieces on the scene.

How much is that?

A million is there.

"Brother Han has a friend who opened our largest leather foundry in China and sponsored me so many times. Gu Xiaobai said.

This is the price of paying a letter to buy "Writings".

Absolutely massive bleeding.

"What about the other funds?" Zhao Xingsheng asked again, now in Gu Xiaobai's laboratory, there is no funding at all.

Moreover, if there is no application for the project, the funds of the laboratory cannot be used casually.

Project funding is now more tightly regulated than ever.

You can look at the various tools and instruments on the scene, there are many of them, and it seems that this room has been directly arranged into a complete studio.

"306 dormitory fee sponsorship. Zhou Xianting raised his hand beside him.

306 Dormitory fees?These tools, wood, and labor costs are not a small amount, but can there be so much money for dormitory fees?

Wait a minute......

306 Shefe doesn't that mean...... Is it the money that 306 has earned so many times by selling songs?

There are actually not many rewards for singing, even if it is a 306 singing group, the money that can be received on the spot is at most a few thousand.

But the 306 singing group, which has been rubbed every time, has so far had three programs on "Singing Street".

Every time Director Shi said that he would pay for it, considering the current popularity of "Song on the Street" and the advertising revenue it brings, how much is this money?

How much does Director Shi have to pay to continue Gu Xiaobai's performance?

I'm afraid that the largest dormitory at Dongyuan University was born!

Zhao Xingsheng shook his head.

The children of today...... It's incredible.

He then focuses his attention on what is in front of him.

The nitrate of these crocodile skins is not particularly exquisite, and there are still some bone plates and hardness remaining, which is to simulate the ancient state of nitration.

After all, the restoration of an instrument is not about perfection or improvement, but about its unique style and timbre.

The drum is a very distinctive drum, and in this world, which drum is covered with crocodile skin?

In order to adjust the sound, the crocodile skin is fixed around it with dozens of different clips, which are connected with bolts to adjust the tension, and pull down the crocodile drum skin and tightly cover the hollowed-out tree trunk.

Gu Xiaobai stepped forward, stretched out his hand, and tapped gently.

The sound of "Fengfeng" came out, and the timbre was dark and bright, which was very peculiar.

"It's a little bit higher and lower, and it's a little tighter. Gu Xiaobai said.

Qin Chuan adjusted the pulling force, Gu Xiaobai knocked again, nodded, and said, "It's almost, the No. 12 bolt is half a turn tighter, and the No. 27 bolt is half a turn looser." ”

Continue to adjust.

Gu Xiaobai tried the pitch again, the pitch was almost there, and he began to adjust the timbre.

After repeating this, Gu Xiaobai felt that there was no problem.

Then he stretched out his hands and slapped on the drum head, sometimes cutting half or a third of the drum with one palm, and striking the edges with the other to test the tone of each edge.

The rhythm of "moving, big, hitting, beating" sounded.

Gu Xiaobai's rhythm is not particularly proficient, after all, he has not actually touched percussion instruments before.

"Xiaobai, you don't play the drums as well as me!" Wang Haixia laughed at Gu Xiaobai next to him, and was rolled by Gu Xiaobai.

But Zhao Xingsheng listened to it next to him, but he had mixed feelings.

This simple rhythm has traveled thousands of years.

It's like an ancient ancestor snapping his chest.

"No problem, fix this drum surface, and then let's change the bottom. ”

Gu Xiaobai didn't have time to sigh anything, he continued to make drums.

Now, this drum is still a long way from being fully restored.

The bottom of the drum is usually used for resonance, but there are also some double-sided drums.

This is not the case with the drum, the main thing is resonance.

But Gu Xiaobai still beat and listened to the timbre, constantly adjusting.

In less than half an hour, the four sides of the two drums were fixed, Gu Xiaobai knocked for a long time, felt it, nodded, and said, "Okay, you can paint the shell decoration and lacquer." ”

"Okay, leave it to us. Qin Chuan licked his lips and began to work.

This kind of work is what he is good at.

He commanded the other single dogs in Dorm 306 to polish the shells into fixed shapes, which were in turn embedded in the pre-dug positions above the drum body.

The abstract and simple animal face pattern appears on the body of the drum.

"You ...... This directly restores the drum?" Zhao Xingsheng felt a little doubtful about life.

"That's right. Gu Xiaobai said, "You think, if we go through the process of competition, we will definitely not be able to compete with Mr. Deng of the Institute of Acoustics." ”

"So...... Are you going to rush in with the drums at that time?"

"Uh-huh...... After all, no amount of theory can compare to the real thing, right?"

"That'...... The theories you told me earlier ......"

"Oh, when the time comes, I can't say that I restored this drum by ear. ”

Zhao Xingsheng: "......"

After talking about the theory for a long time, it turns out that in the end, all the acoustic foundations are just a pair of ears for you?

At this moment he just wanted to roar.

This is Gu Xiaobai's acoustic laboratory?

This is obviously Gu Xiaobai's ear metaphysics laboratory!

Gu Xiaobai, you are a scientist!

Please use the scientific way and compete with dignity!

It's not good, it's very bad!

Gu Xiaobai stretched out his hand and lightly tapped the two drums a few times, and in his memory palace, the complex mode shapes were constantly changing and superimposing.

The library system has been upgraded again!

It is true that he relied on his ears, but it is impossible for other people's ears to hear the vibration shape of the face.

That's his killer feature.

(Note 1: I saw that the information said that the Chinese alligator is forbidden for commercial use, and the existing population has the problem of inbreeding, and the continuation of the race is difficult, but the news also says that the Chinese alligator meat can be eaten, and there is a plan to "raise crocodiles with crocodiles", but there is no circulation of the skin of the Chinese alligator in the market, so it should be a small scale, so it will not harm its own Chinese alligators, but harm other people.) ）

Note 2: The content of this chapter is made up by Uncle Ha based on acoustic data, archaeological data and research on crocodiles, please do not take it seriously. In addition, I always feel that the drum that has been restored now cannot be called a drum at all. You don't use crocodile skin, just imitate it, can you call it a drum? The material is different, can the timbre be the same? Right? Of course, using crocodile skin is too expensive to use......

Note 3: When I read the information, I saw a lot of stories about Chinese alligators, which was embarrassing. This guy is such a stupid thing, it's a pity that he looks too ugly, otherwise he will be another roll. ）

：。 ：