Witch doctors have long discovered that they can control the amplitude and frequency of sound waves to give sound a variety of functional properties;

At the same time, they borrowed from Warcraft spells, and had the ability to create and receive sound waves in different frequency bands through rune spells.

After a period of actual use, they calculated and further defined the accurate values for each frequency of subsound waves according to the vibration frequency and other standards, and figured out the detailed relationship between the various values.

Since then, the witch doctors have truly opened the door to research, and their understanding and application of the field of sound waves have gradually reached a stage that is different from the past.

However, the various theorems and axioms obtained during this period are really too obscure, and usually only witch doctors and witch medicine disciples have the opportunity to really use them when they are conducting academic research.

Therefore, in order to be popularized and more users can have a general understanding of the relevant concepts;

The witch doctors then divided it into rough, less rigorous band bands from -10 to +10 according to the 'recognizable range'.

Among them, the natural voice of the trolls is between the -3 and +3 frequency band, and because this interval is the auditory recognition area of most 'non-hearing' normal monsters and animals, it is defined as the 'normal band'.

However, the physical ear recognition range of ordinary trolls is beyond the upper and lower extremes of their own voices, reaching the -4 to +4 frequency band.

Therefore, the two wave frequency ranges of '-4' and '+4', which are outside the normal range and within the troll's hearing, are separately defined as 'troll special bands', and each has its own application field.

The former, which is usually used between armies, is the main means used by flag officers to convey commanders' orders when conducting 'short-distance direct audio transmission' within 10 kilometers.

The latter is used in the field of 'short-range direct audio communication';

For trolls, the '+-4' band is still within the limits of the recognition of the human ear, but for many creatures, it is a silent state;

Taking advantage of this difference, the sender can use spells or totems to raise and descend tones, producing +-4 band tones that they can't get through their voices.

And in this process, the magic or totem can also constrain the direction of sound wave transmission to a certain extent.

Recipients of voice messages who are also trolls, even if they are in a non-blessed state, can directly hear valid information from the sound waves that are distorted by the spell within a certain range through their own physical ear recognition, and there is no need to translate them in the middle.

As a result, the trolls have achieved a sense of 'private communication'.

This may be closer to Nesta's previous life, similar to 'transmission into the secret' and other means;

And in the previous time against the cave wolves, the witch doctors have used this technique, and it has achieved good results.

However, due to the band above +3, it will dissipate sharply in the air;

Therefore, even if both the sending and receiving parties have the blessing of spells and totems, the realization of the scheme has a fairly strict distance limit.

And both of them, because their frequency bands are beyond the upper and lower limits of the troll's vocal range, they also need to use spells or totems to help them form at the sending end.

However, at the receiving end, because it is in an area that can be directly captured and recognized by the naked ear, it usually does not need the corresponding spell or totem blessing to achieve the purpose of delivering the message.

The non-flesh-ear recognition area outside of '+-4' is named 'Super Secondary Wave', and it also has its own application or development direction.

Among them, the former, due to its good directionality, high interface waveform conversion ability, strong penetration ability and other characteristics, has relatively concentrated applications in animal and plant medicine research and materials science exploration.

In addition, due to its high carrying energy and strong penetration, it has gradually become more lethal in the future development direction.

This is mainly due to the fact that witch doctors have observed the strong penetrating power it exhibits when it is in both solid and liquid states, and when it carries a large amount of energy, it can also cause the particles of matter to vibrate at high frequencies, thus increasing the temperature of the area.

However, if the intensity continues to increase, the sound waves can also be transmitted between the 'liquid with small bubbles', causing the bubbles to shrink and expand to the point of a violent explosion.

Because the vast majority of living organisms are made up of cells, and the cells themselves belong to the category of 'liquids with small bubbles';

Therefore, the witch doctors who observed this phenomenon thought that they could use it to develop a 'high-frequency sonic spell' that would be lethal enough to take advantage of it.

However, this magic research is still in the experimental stage, and due to the frequency limit of the 'occurrence end', the witch doctors have not been able to realize it for the time being;

However, in the more complex group casting mode, the breakthrough of the 'occurrence end' to the '+7 wave frequency' is just around the corner;

Perhaps then, the witch doctors will be able to cast spells in groups to emit high-frequency ultrasound waves that are lethal enough.

On the 'audio application side', because ultrasonic waves are very easy to attenuate in the atmosphere, it has no better performance for the time being, except for the 'close-range direct audio communication' that uses the 'troll special band' mentioned earlier.

The latter, 'infrasound', is the opposite.

Its sound wave frequency is low, the wavelength is long, the diffraction is strong, the attenuation is small, and the propagation distance is long, so it has a broader application in the field of 'sound'.

More specifically, the application of secondary waves is usually found in the four sound intervals of medium range, medium and long distance, long range and ultra-long distance.

Since all four of them use wavelengths below '-4', the signals they send and receive are no longer supported, and they are directly understood by the brain in the form of 'recognizable audio'.

Therefore, if you want to use its characteristics to transmit information, both the sender and the receiver need the assistance of corresponding spells or totems, and through the translation of the contract code, to achieve effective application.

Among them, 'medium distance' refers to the sound transmission in the '10-100 km' section, which is mainly achieved by using the '-5 infrasound band'.

The witch doctors' application of sonic spells was actually later than the time when they had totem technology, so they were totemized soon after the spell was transformed;

The success of totemic has successfully allowed the application of this method to continue to extend downward from the level of witch doctors, so that it has a wider range of use scenarios.

In the early days, due to the lack of education and the needs of war, the users of this type of totem were limited to witch medicine practitioners;

Because only they have the ability to apply the method in a short period of time.

However, with the popularization of education and the continuous progress of educational methods, more and more ordinary trolls have been able to apply them through professional learning.

And they are the main force of technical trolls such as communicators and communication soldiers in the ruling government and the army.

These techno-trolls are not witch doctors, nor are they witch doctors;

For them, it is true that with the blessing of spells and totems, the wave frequency acceptance range can continue to extend downward to extremely low areas;

However, in practical applications, their signal recognition capabilities are limited to the '-5 secondary band', that is, the '10-100 km medium-distance audio range'.

Therefore, this is also the limit of regular individual communication between the army and the ruling government, and if you want to extend the effective transmission distance of voice to a greater distance, you must use the relay method.

As for the lower bands, because the signal has been relatively seriously mixed with the natural background, and its degree has exceeded the scope of real-time recognition by the brain of ordinary trolls, it also has relatively higher application limitations.

Among them, the information transmission in the area of 100 km to 500 km, that is, the definition of the 'medium and long-distance audio interval', needs to be achieved by using the infrasound signal of the '-6' frequency band;

The signals in this interval need to be screened and parsed from the complex signal background with the help of a series of complex algorithms, with the help of a series of complex algorithms, and further translated into text.

Generally speaking, only witchcraft practitioners who have undergone specialized training, as well as some professional communication soldiers with excellent professional skills, can be fully qualified for this job;

And they, of course, have also become the backbone of the Ministry of Communications and the Military Command Headquarters of the ruling government, and have undertaken the corresponding high-level information transmission tasks.

As for the further downward realms of '-7th sonic waves, long distance' and '-8 to -10th sonic waves, ultra-long distance', they are no longer the level that can be achieved by the 'ordinary brain', they are special bands that can only be 'used' by witch doctors and advanced witch doctors, respectively.

In both ranges, the frequency of the sound waves has been reduced to an extremely low point, and the natural background sounds are extremely complex;

Without the support of a strong brain, it is impossible to use pen and paper calculations to find and parse a specific signal in this kind of noise.

Among them, the brain computing power of the vast majority of witch doctors is limited to the recognition of signals in the range of 'long distances within 1,000 kilometers';

These non-advanced witch doctors, although their physical ear recognition range, are still within the normal range of -4 to +4;

However, with the blessing of their magic ability, they can expand the upper and lower limits of the physical ear to 3 frequency bands, so that their voice signal reception range can reach the range of -7 to +7, and they still have enough brain power to parse the part of the information they need.

If you were to make an estimate of their capabilities based on the size of the Black Forest..... Then these witch doctors should be able to receive infrasound signals from the headquarters from the No. 3 sub-base on the west bank of the Black River.

As for the four existing advanced witch doctors, they are different in this respect;

After advancing, their flesh-ear sound wave recognition range has been increased by 1 natural level in addition to the upper and lower limits of ordinary trolls, reaching the auditory recognition ability in the -5 to +5 frequency band.

If it is supplemented by the blessing of magic, it can realize the full-band identification of the existing limit range, which may not be too rigorous....

In fact, when the witch doctors calculated the upper and lower limits of the sonic frequency band, they used the recognition limit of the four advanced people such as Nesta with the blessing of magic to obtain the value.

And the range of voice signal acceptance of the four of them, on the basis of non-advanced witch doctors, I don't know how much distance they have crossed.....

At the very least, the long span between the east and west of the Black Forest, and the complex topography of the northern mountains, could not really limit their ability to use ultra-low-frequency neoplastics to receive signals;

At this stage, it is only because it is impossible to make accurate estimates that a model lake definition of 'ultra-long distance 1,000 kilometers away' is given.

The reasons for such disparities lie mainly in three aspects;

First, there is the disparity in the level of living beings in the flesh;

Nesta and the other four have inherited the sensitive and abnormal hearing system of the troll race;

And when they advanced, they made a sublimation on the original foundation, which created a difference between them and the rest of the trolls.

The ability to hear '-8 to -10 infrasound bands' and '+8 to +10 ultrasound bands' without being damaged afterwards is a distinctive feature of this stage.

This is also confirmed in the elf girl;

At this time, her naked-ear sound wave band recognition range also reached the level of advanced witch doctors, within the range of -5 to +5;

With the blessing of the technique, it has been able to receive the '+-8' frequency band normally, and there is no abnormal feeling;

It was only when she went up and down the band outside of '+-8' that she felt dizziness and other adverse reactions....

However, this is only because she is still in the growth period and has not fully developed her physical talents, and if she grows according to this trend, she will sooner or later acquire the corresponding abilities.

Let's look at the non-advanced witch doctors....

First of all, they do not have a substantial gap with ordinary trolls in terms of the range of physical ear recognition;

Secondly, once they forcibly enter the frequency band other than '+-7', they will experience obvious physical discomfort, and in severe cases, they will lose their hearing for a short time.

From this, it can be judged that the corresponding structures in their bodies have not yet reached a certain level.... This is known as the 'physical gap in the biological hierarchy'.

Second, there is a gap in brain computing power;

It is also in the '-7 infrasound' interval, and the recognition and analysis speed of advanced witch doctors is much faster than that of ordinary witch doctors;

In the same '-6 infrasound' range, the witch doctors' recognition and analysis speed is also much faster than that of the apprentices;

These two comparisons have already shown the difference in computing power quite obviously.

Third, there is a gap in knowledge reserves.

'Being able to hear' is not the same as 'equal recognition', although the elf girl shows a super ability to receive signals, but when the signal is not a language, but a code, she does not have the ability to understand it;

When ordinary trolls and communication soldiers are respectively given the ability to receive voice messages in the same frequency band by the totem, the former, who has not learned the system, naturally does not have the ability to obtain information from them like the latter.

Finally, there is one more point that deserves special emphasis.....

Although advanced witch doctors can rely on the 'ultra-low-frequency infrasound' reception ability, they can listen to infrasound signals thousands of kilometers away;

But this does not mean that Nesta and the other four can effectively communicate at the east, west and west ends across the entire Black Forest.

In fact, they didn't have the ability to 'emit' infrasound at that frequency, and all they had heard in previous attempts was 'natural background sounds'.

The 'ability to recognize', which has been emphasized before, actually refers to their ability to distinguish between 'natural sounds in the background'.

Therefore, when the fanged witch doctor and Ishshara went to the northwest mountains one after another, they could only communicate with the headquarters intermittently through the permanent signal relay station set up at the remote end, and the sending and receiving process was extremely complicated.

At this stage, witch doctors can only generate '-6 medium and low frequency infrasound' and '+6 medium and high frequency ultrasound' through spells and other means;

Therefore, there is no qualitative gap between the signaling capabilities they can achieve and the highest level of communication at the Ministry of Communications of the Executive Government....

And even if there were, it was only in terms of efficiency;

It takes the time of the communication department in the unit of light hours, and it takes more than a dozen technical trolls to work together to calculate a set of information;

The witch doctors may only need a dozen light points to get the specific contents.

And the same information, Nesta and the other four may only need a few light minutes to parse.

The so-called gap is actually 'only'.

~~~~~

With the support of the above-mentioned infrasound communication technology, the Department of External Exploration and the Department of North-South Exploration of the ruling government have successively carried out explorations in two directions in recent years.

The southern end is not bad, the south of the Black Forest is a vast desert area, as long as you bring sufficient supplies, the exploration department can basically set up a signal relay station there at will without any scruples, so as to reach contact with the front-end exploration team;

But the situation at the North End is a bit more complicated.......

~~~~~

By this time, several teams of scouts had arrived at the volcano and were conducting a thorough investigation of the organisms inside.

It's a pity that Nesta and the other witch doctors didn't have the inspiration to develop a 'combat power detector' like Dragon Ball, which made the search a bit inefficient.

The members of the exploration team could only guard the crater one by one, waiting for the creatures to occasionally pop up and 'identify' them with the naked eye.

"Damn... Is this the guy the one you just had? ”

"It's like... It doesn't seem like it... Gee... I can't tell the difference, I feel like they all look exactly the same..."

"What can I do..."

"I don't know.... But what we're looking for is their boss, so we should be able to judge it based on their size, right? ”

On the side where the communication is going well, it has encountered problems on the exploration side.....

The creatures in the volcano don't seem to be within the range of the trolls' facial recognition capabilities, and their lava-covered faces and bodies barely differ in any significant way.

The only 'size' factor that can be used as a reference is only a guess based on the cave wolf, and in fact it is not necessarily rigorous;

At the very least, the three of them are now slightly smaller than the ordinary trolls....

Although, the advanced witch doctors are still growing taller, among them, the earliest advanced Esara, after all these years, his height has also approached three meters again;

It looks like in a few years, and it seems that she will be able to match or even surpass the rest of her troll form again.

But at least it also shows that high-level creatures are not necessarily taller than their low-level compatriots....

In addition, the volcanic complex is almost entirely active, and the smoke of the pass affects the trolls' ability to observe with the naked eye.

So, I don't know if the troll was impatient, he closed his eyes first, ready to distinguish by hearing....

This is a terrible sound, and it really found some clues for him.