How is this sound effect made in 3D?

First of all, let's talk about the positioning function of the human ear to sound. Both ears have positioning function. Monoear localization is mainly vertical localization, which is an auditory effect produced by the reflection of incident sound waves by various parts of auricle, which is weaker than binaural localization. Binaural localization is mainly in the horizontal direction, which is the auditory effect produced by the different differences when the sound waves emitted by people reach people's ears. The positioning accuracy is 10- 15, which is more important for people's daily life. It is more accurate for sounds from the front and worse for sounds from the rear. In 3D sound effect, the principle of binaural localization is used-binaural brain locates sound through sound level, time difference, phase difference and timbre difference. The most important positioning basis is sound level difference and time difference. Localization of sound level difference: the human ear is extremely sensitive to sound level. For example, under the condition of audible sound level (sound level is 0dB, sound intensity is about 10- 16W/cm 2), the vibration amplitude of tympanic membrane is only10-1m, and the vibration amplitude of cochlear base is only/kloc-0. The localization of sound level difference is caused by the same sound source receiving different sound levels in both ears. For example, when the sound source shifts to the left, the sound wave can reach the left ear directly, while the right ear is shielded by the head, so that the sound level heard by the left ear will be greater than that of the right ear. The more the sound source is biased, the greater the sound level difference, and the maximum sound level difference can reach about 25dB. The sound level difference localization is the most important localization method for the sound source at a short distance, but the sound level difference localization effect is not good for the low frequency sound at a long distance. Time difference location: it takes time for sound waves to propagate in the air, so when the sound source is not directly in front (directly behind), the ear on the same side of the sound source will hear the sound earlier, while the other ear will hear the sound later. This tiny time difference (less than 0.6ms) can also be distinguished by human ears, and finally it will be transmitted to the brain for analysis to get the position information of the sound. Time difference is useful for determining the direction of sound with different frequencies; Time difference mainly refers to the time difference from the moment when the sound first reaches the human ear, so the human ear has a stronger directional ability for transient sounds and sudden sounds such as gunshots and percussion instruments. For this kind of sound, people can make better use of time difference to make directional information. Finally, talk about the production of 3D sound effects. If you put the same sound source in front of you at an equal distance of 30 from left to right and play the same sound with a time difference of 0, when you only judge by hearing, you will think that only the previous sound source is playing sound to you; If the volume of one of the sound sources increases gradually, you will feel that the sound is moving in an increasing direction, that is, using the sound level difference of the sound to create a simple 3D sound effect. Simply put, 3D sound effect is to play the sound with two-channel speakers (headphones) respectively, and make people's ears have the illusion that the sound comes from different directions through the subtle differences (volume and time difference) of the two channels, thus creating an immersive feeling. At present, 3D sound effects can simulate sounds from different directions, not only in the horizontal plane, but also in the vertical direction, and even achieve the effect that sounds move continuously from near to far, from far to near, from left to right and rise around.