Zhang Lingjun shook his head and said with great certainty: "No, I can be sure that it is the sound of footsteps, the sound of high heels colliding with the hardened ground. I have heard the sound of such shoes before, and it is nothing like the sound I heard now.

Not bad."

Old John said: "I believe in brother Lingjun's ability, and I also believe that his morality will not lie. There is no need to get entangled in this aspect."

The black policeman said: "I didn't say he lied, nor did I say I didn't believe him. It's just that the good swimmer died of drowning, so I thought he might be confused.

"The sound of walking in high heels does not have any specific and directional information, and it itself is relatively vague.

"At the same time, that recording does not provide reference for comparison with Ruan Xing's previous habits. The sound of high heels does not conform to the development logic of the things described in the previous video and recording, and has no causal connection with the subsequent recording. It is really abrupt.<

/p>

"In comparison, the sound of marbles is more reasonable. The marbles I am talking about are not real marbles, but the steel bars and cement make noise due to unknown chemical or physical effects over time. This has been scientifically proven.

explained.

"This phenomenon usually occurs in buildings. You should occasionally hear it here, and this complex is often used as a setting in detective novels. Should we have a better understanding of this?"

Zhang Lingjun said: "First of all, novels that use this phenomenon to develop the plot are usually horror stories, but detective novels, which is not professional.

"Besides, I know what you are going to say, even better than you.

"Because the reinforced concrete in the main body of the building has different specific heat capacities and shrinks at different frequencies, pinball sounds may occur due to changes in temperature between day and night.

"Concrete is eroded by mold and other things, forming gaps and holes. The steel bars wrapped in vegetation cannot be fixed by the original force, and are suddenly released, bouncing back and forth, causing the sound of marbles.

"Hollow prefabricated panels (also called floor slabs in some places) have sand in the middle, and small cement blocks will crack and collide in the hollow holes, creating a sound similar to marbles hitting the ground.

"I major in civil engineering, and I have often heard this kind of sound in the environment I have lived in since I was a child. I am very familiar with it. Therefore, I can detect the natural sounds originating from building materials and the sounds at this time.

are different.

"One frequency is faster and crisper, and the other is a little thicker and more regular in frequency, which is the sound of high-heeled shoes footsteps."

Old John looked at the black policeman and said, "There is really no need to get entangled in this aspect. Whether the sound was footsteps or marbles, she did not enter the door, so she would not have anything to do with the murderer, and the detection of the case would not be affected."

How can I help?"

"How could it not be helpful?"

The black policeman said: "If the footsteps mean that someone appeared at that sensitive time, he may have gone wrong, but it is also possible that this person knows something. He may have seen or heard something at close range. At least he can be sure of Ruan Xing's home at that time.

Some of the conditions at the door, as rare clues at the time of the crime, are still very important to make a breakthrough now that the investigation of the case has been stagnant due to the lack of any progress. This is also the reason why I asked.

"If marbles mean no one, this can also provide value for the reasoning and detection of the case..."

"It's just the sound of high-heeled footsteps..."

Zhang Lingjun said, tapping the computer keyboard and playing the audio again, click click click...

"I can even tell what these shoes look like."

Old John paused and said: "Brother, you are a little too fantasy. Really, if you say that, I can't help but doubt you."

Zhang Lingjun said: "The footsteps are so far away from the microphone, and there is a door as a barrier. It is such a small and broken sound. It is normal for normal people to have doubts about my firm judgment that it is footsteps and the appearance of the shoes. I can understand it.

.

"In fact, just based on the association of this sound, it is indeed impossible for me to directly draw such a certain directional thing as a certain shoe.

"The reason why I made such a judgment is because I have an impression of the sound of this pair of shoes due to my previous experience.

"I'm not trying to guess what caused it based on the sound, but I'm going to match the sound with the thing that most closely matches my memory to see if it's perfect, just like I previously denied that it was the sound of marbles caused by the aging of the building.

That way."

Ta da da…

Zhang Lingjun moved his ears, slowly chewing and savoring the small but clear sounds with many distinctive and specific characteristics in his mind.

"Listen... when the shoe hits the ground, is there a click..."

Old John and the two shook their heads, "No."

"Yes, listen carefully."

The two listened carefully, then shook their heads, "Still not..."

Zhang Lingjun had no choice but to constantly process, amplify, and de-noise the sound. After a lot of effort, the two of them heard the faint clicking sound interspersed with intentional sounds that were different, "Well...it seems to be...

Here we go...this is..."

Zhang Lingjun said: "This is the sound of a wind chime that is popular in Cambodia. Local legend says that as long as the wind chime is shaken, the sound can be transmitted to relatives far away so that they can hear it."

After hearing this, the two of them stared at Zhang Lingjun in silence.

A face said: This is a wind chime, where did the sound of the wind chime come from?

Another face wrote: What does this sound have to do with shoes? They are not even close.

Zhang Lingjun explained: "On the east side of Shangcheng District, Dien Bien City, on the third floor of a famous shopping mall called 'Little Guangdong', there is a private custom shoe store called 'Shiyun' that doesn't look very big.
p>

"The boss turned out to be the master chef of the state-owned shoe factory in Dien Bien. The shoe factory failed due to poor management ten years ago. After that, he did not choose to accept the high-priced invitation from his peers, but opened his own shoe store.

"He naturally has the confidence to do this,

"Everyone knows that due to historical reasons, in that era, materials were relatively scarce. Not many people could wear leather shoes produced by factories, and even fewer people could wear leather shoes made by skilled masters.

Not an ordinary person.

"And in the new century, these people will not become more ordinary, but will become richer.

"You must know that if many people are used to wearing clothes and shoes from one brand and made by a tailor, regardless of comfort or style, they will not be willing to change them again.

“Especially for leather shoes, they don’t have as many patterns as clothes, and they don’t pursue design as much, so they leave more room for private customization.

"In addition, after entering the new century, some local people can't help but feel a sense of panic, or a little inferiority complex, when faced with a strange era and various foreign goods.
Chapter completed!