What Is a Forward Echo?

When sound is projected onto a large area with a distance from the sound source, part of the sound energy is absorbed and the other part of the sound energy is reflected back. If the listener hears the sound directly from the sound source and the reflected back The time interval of the sound is more than one tenth of a second (in the air at 15 ° C, it is reflected at least 17 meters away from the sound source), and it can distinguish the reflected sound of two sounds called "echo". If the speed of sound is known, the distance from the reflecting surface to the sound source can be calculated when the time interval from when the sound is emitted to when it is reflected back is measured.

When sound is projected onto a large area with a distance from the sound source, part of the sound energy is absorbed and the other part of the sound energy is reflected back. If the listener hears the sound directly from the sound source and the reflected back The time interval of the sound is more than one tenth of a second (in the air at 15 ° C, it is reflected at least 17 meters away from the sound source), and it can distinguish the reflected sound of two sounds called "echo". If the speed of sound is known, the distance from the reflecting surface to the sound source can be calculated when the time interval from when the sound is emitted to when it is reflected back is measured.

Echo Basics

Word : Echo

Pinyin : huí shng

Phonetic :

Synonyms : echo echo echo ^[1]

Echo

[echo] The repetition of sound caused by the reflection of sound waves; it can also refer to the reflected ultrasound signal

Echo Citation Explanation

1. Sound that is reflected back by an obstacle and heard again. Jin Jin's "Little White Goose Is Here": "The shepherd child shouted aloud: 'Little White Goose! Where are you?'

2. Refers to the signal from the whistle when the ship arrives at the dock. Mao Dun's "Midnight": "Yes, yes, Master. I have heard (Steamboat) echo."

3. Response, reaction. Lu Xun's "Lace Literature: On Mrs. Qin Lizhai": "Only the recent suicide of a family of four Mrs. Qin Lizhai and her children, but many echoes were heard. Later, there was a suicide with this news note. Its impact is huge. " ^[1]

4. Thoughts after doing something.

Echo related

New research says we all have the potential to gain echolocation

For many years there have been legends of people who are proficient in echolocation technology, which is commonly used by bats and dolphins to map and understand their surroundings. American-born Ben Underwood lost his vision due to cancer at the age of three and began using a series of percussions to find his way. By the time he was a teenager, Underwoo was already adept at roller skating, which confirmed that he had the magical ability to accurately understand the surrounding environment. He can even play video games, but this ability has nothing to do with his echolocation skills, but because of his highly sensitive hearing. Similarly, Lucas Murray of Dorset, under the training of Daniel Kish, the founder of the "Accessible World for the Blind", also mastered this technique at the age of 7 ^[2] .

A team formed by the University of Southampton's Institute of Sound and Vibration and the University of Cyprus conducted experiments using an anechoic chamber. The room is soundproof and its walls absorb sound waves to eliminate background noise. The research team used different frequencies of sound in it, while some blind and normal people tried to use them to determine the position and orientation of objects. They found that frequencies greater than or equal to 2KHz allowed testers to accurately locate objects. Their research means we all have the potential to become echolocation experts.

"Some people are better at it than others, and blindness doesn't automatically gain good echolocation, but the reason is unknown," said study author Daniel Rowan. The research team found that the farther away an object is, the more difficult it is to determine Location. The tester was able to identify the object at a distance of 1.8 meters, even without directly facing it. The research team believes that allowing testers to shake their heads at will can better determine the distance of objects. Researchers hope the results of this research will help develop devices that are easier to locate in the echo. The study author wrote: "The next study will be extended to take into account other relevant factors related to realistic echolocation."