What is Echo: Definition and 37 Discussions

In audio signal processing and acoustics, echo is a reflection of sound that arrives at the listener with a delay after the direct sound. The delay is directly proportional to the distance of the reflecting surface from the source and the listener. Typical examples are the echo produced by the bottom of a well, by a building, or by the walls of an enclosed room and an empty room. A true echo is a single reflection of the sound source.The word echo derives from the Greek ἠχώ (ēchō), itself from ἦχος (ēchos), "sound". Echo in the Greek folk story is a mountain nymph whose ability to speak was cursed, leaving her able only to repeat the last words spoken to her. Some animals use echo for location sensing and navigation, such as cetaceans (dolphins and whales) and bats.

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  1. Wrichik Basu

    Changing proxy server for WiFi in Amazon Echo Dot and Fire TV Stick

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  2. P

    I If I clap once to a wall, and then walk forward, will I hear an echo?

    This is a diagram: ------------ reflective wall X --> Y I stand at position X and clap towards a reflective wall. Theoretically, could I walk to some point Y, where there is constructive interference between my clap and the reflected clap, resulting in my hearing a much louder sound. Is...
  3. binbagsss

    MATLAB Matlab: echo generator question

    The task is to given an input column vector (with values between -1 and 1 representing the digitized data), fs the sampling rate, delay to represent the delay of the echo in seconds, amp specifying the amplification of the echo, to add this echo to the original signal after delay seconds. Other...
  4. Y

    MRI Spin echo sequence and STIR

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  5. Simon Peach

    B Exploring Echoes of Electromagnetic Wave Lengths

    In the electromagnetic wave lengths say from x-rays to the 21 cm hydrogen line, the wave has a wave length. When it hits a receiver, eye, camera sensor whatever, it is turned into an electrical signal that can be interpreted by that device. Now we get to my question, is there an echo of that...
  6. J

    Pulse echo technique to find the distance of the Moon

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  7. R

    When does a sound echo not disturb its listener

    Homework Statement :[/B] At a prayer meeting the disciples sing JAI RAM .The sound amplified by a loudspeaker comes back after reflection from a building at a distance of 80 m from the meeting. What maximum time interval can be kept between one JAI-RAM and the next JAI-RAM so that the echo...
  8. J

    I T2 relaxation and Spin Echo of protons

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  9. A

    What do echo and reverbation have in common?

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  10. Xoloti

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  11. SpicyWassabi101

    Solve Physics Echo Problem: Air Echo Returns 1.33s Later

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  12. B3NR4Y

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  13. B

    Difference between sound echo and mirror reflection

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  14. K

    Is there even a scientific reason for this

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  15. R

    How long will it take for the echo to return

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  16. R

    Calculating the Distance of a Sonar Echo

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  17. N

    PHP HTML and PHP issue: display HTML form variables using PHP echo

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  18. jegues

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  19. S

    Distance of building related to echo

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  20. Z

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  21. F

    Cause of echo in VoIP conversation

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  22. A

    Find difference in echo times, doppler shift?

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  23. M

    How to find distance given echo time. (WAVES)

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  24. T

    How Do Echo Timings Help Calculate Cliff Distances?

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  25. D

    Comp Sci What is the Best Way to Create a Secure Password Prompt in C++?

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  26. W

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  27. M

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  28. T

    Calculating Well Depth with Doppler & Echo Effects

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  29. R

    Distance between earch and the echo of the Tycho Supernova

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  30. Simfish

    Dennett and his Echo Chamber Hypothesis

    Sweet Dreams pg. 168-170 "Episodic memory is not for free. One idea is that it is the very echoic power that makes episodic memory possible. Animals remember thanks to multiple repetitions of stimuli in the world. We remember, it seems, one-shot, but really, it isn't just one-shot. What we...
  31. B

    Radar echo and clock synchronization

    Please help me in the folowing problem: It is well known that the radar echo (police radar) establishes a relationship between the period T(e) at which a stationary observer emits successive light signals and the period T(r) at which he receives them back after reflection on an object that...
  32. A

    Submarine echo physics problems

    Homework Statement A submarine on the ocean surface gets a sonar echo indicating an underwater object. The echo comes back at an angle of 20* above the horizontal and the echo took 2.32s to get back to the submarine. What is the object's depth? Homework Equations delta of theta =...
  33. marcus

    Kodama means echo or spirit of the trees

    Kodama means "echo" or "spirit of the trees" I just thought you might like to know :smile: AFAIK the Kodama state was first written in 1988 by Hideo Kodama It seems the Japanese have what they call "clans" and there is a Kodama clan. There have been other famous Kodamas besides Hideo...
  34. M

    Ocean Depth at 7.07s Echo Time - 1.22311 km

    A geological survey ship mapping the floor of the ocean sends sound pulses down from the surface and measures the time taken for the echo to return. How deep is the ocean at a point where the echo time (down and back) is 7.07 s? The temperature of the seawater is 25°C. Find the answer in km...
  35. E

    Solve the Stone Drop Problem: Acceleration of 9.8m/s^2

    i need help on the following problem: "carol drops a stone into a mine shaft 122.5 m deep. How soon after she drops the stone does she hear it hit the bottom of the shaft?" i know that the acceleration is 9.8m/s^2 but i can't use it as speed in the speed=distance/time equation please help me...
  36. L

    News: An ECHO of Black Holes

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  37. T

    Why a duck's quack doesn't echo

    A duck's quack doesn't echo, and no one knows why. Can physics explain this fact and how?
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