Interactive simulation of sound reflection, echo calculation, and wave visualization with adjustable distance parameters
Sound reflection occurs when sound waves encounter an obstacle and bounce back. An echo is the reflected sound that arrives at the listener's ears after a noticeable time delay. The human ear can distinguish between the original sound and its echo when the time delay exceeds 0.1 seconds, which corresponds to a minimum distance of 17 meters (assuming sound speed of 340 m/s).
The echo time is calculated as t = 2d/v, where d is the distance to the reflecting surface and v is the speed of sound. The factor of 2 accounts for the round trip (sound travels to the wall and back). When this time exceeds 0.1 seconds, humans perceive a distinct echo rather than reverberation.
When the reflection distance is less than 17 meters (delay < 0.1 s), the reflected sound arrives too quickly for the human ear to distinguish it from the original sound. This creates reverberation - a gradual decay of sound that adds richness to music. Clear echoes occur at greater distances and can be used for distance measurement and acoustic ranging.
Ships and submarines use sonar to measure water depth and detect underwater objects by calculating the time delay of sound reflections.
Architects design concert halls to optimize reverberation time - too little creates dead sound, too much makes speech unclear.
Ultrasound imaging uses high-frequency sound waves and their reflections from body tissues to create internal images.
Buildings use sound-absorbing materials to reduce unwanted echoes and improve speech intelligibility in large spaces.