Starting Off Survival With A Small Treehouse

As for why only he can hear the sound and Zhao Xiaochuan cannot...

He probably knows why.

It’s probably because this sound is something normal people cannot capture under usual circumstances.

Infrasound!

Infrasound refers to sound waves with frequencies between 0.0001Hz and 20Hz.

And the human hearing range is 20-20000Hz.

This is a sound wave outside the human hearing range!

As for why Xu Xin can hear this sound...

It’s because he currently has hearing amplification!

Hearing amplification has even expanded his auditory frequency range!

This is why he can hear this sound, which even at the loudest would be undetectable by human ears!

The symptoms they just experienced are basically consistent with the harm caused by infrasound.

Infrasound at certain intensity can stimulate the human nervous system, causing fear, agitation, dizziness, nausea, vomiting, difficulty swallowing, loss of appetite, fatigue, weak energy, and tinnitus.

Moreover, certain frequencies of infrasound can resonate with the vibration frequency of human organs, causing strong harm to the body, and at extreme danger, it can even cause death!

At the same time, infrasound has a low frequency, decays very slowly, and has a long wavelength, allowing it to bend around certain large structures via diffraction, and some infrasounds can even circle the Earth several times.

On Earth, sound weapons are made based on the principles of infrasound.

This is an extremely terrifying sound that can kill invisibly.

Unexpectedly, the soft creature beneath the prison, just by emitting sound, is a lethal weapon, posing such a huge threat to them!

”So what exactly is going on, Brother Xin?” Zhao Xiaochuan’s complexion had improved slightly, ”Not just us, but those bugs outside are extremely strange too, they’re huddled in the corner motionlessly, and even those giant beasts are lying still on the ground, seemingly afraid of something.”

”It was my accidental operation just now.”

Xu Xin rubbed the little head of Keke, who was still trembling in his arms.

The behavior of the underground creature in the prison matched his speculation.

If the sound just now was the sound of the giant beast, then the fear in these underground creatures seemed normal.

They are confined in the prison and cannot run around, so other than trembling and playing dead, they can’t do much else.

Then Wen Guixin and Wang Lei arrived.

”What happened?”

”Xu Xin, did you press some button? Hey, why is the screen on?”

The two of them walked into the control room and immediately saw the activated screen.

Wen Guixin immediately walked over to examine the screen and then turned to Xu Xin, asking, ”So what button did you press just now? I almost thought this prison was going to be launched like a rocket, and I’m dizzy with rockets!”

Their complexions were also a bit pale, after all, they were also affected by the infrasound attacks a while ago.

Although they couldn’t hear the sound, these effects were very real.

Fortunately, everyone present was not ordinary, and this metal prison had blocked most of the sound, so the angry roars a moment ago did not have too much impact on them.

After recovering, it was simply uncomfortable.

”Let’s go out and have a look, I’ll tell you as we walk.”

As they walked out the passage and looked out over the soft ground, Xu Xin had already explained to them what had just happened.

”So...” Wen Guixin pointed at the soft ground below with some disbelief, ”The reason for the shake and for our discomfort was all because of this big guy below!”

”Isn’t this kind of scary...?” Wang Lei looked straight down at the soft ground, gulping.

”Just its roar made us... this uncomfortable? And we are inside the prison. If we were outside, directly exposed to the sound attacks...” Zhao Xiaochuan also couldn’t imagine.

The ground outside had already returned to calm, completely obscuring the fact it had deformed just now and opened a ”big mouth.”

The four exchanged looks.

They still hadn’t figured out what they were supposed to do, but dangers kept revealing themselves one after another.

This place is truly dangerous!

No wonder it’s an underground facility...

”Whee...” Keke finally regained her senses and lifted her little head from Xu Xin’s embrace, glancing at the ground below before burying it again, letting out a muffled sound, ”Whee!”

Keke probably knew from the very beginning that this was the roar of the giant beast.

Wait...

If it was indeed a roar...

Might it contain some meaning?

”Keke!” Xu Xin lifted Keke to his face.