Question

.What is Echelon effect?How can it be avoided?​

Answer 1

Answer:

If there is regular structure similar to a flight of stairs or asset of railways in the hall, the sound produced in front of such a structure may produce a musical note due to regular successive echoes of sound reaching the observer. Such an effect is called echelon effect.

To avoid echelon effect, the staircase must have to be covered with carpets. Extraneous noise. The extraneous noise may be due to the sound received form outside the auditorium and the sound produced by fans inside the auditorium.

Answer 2

FACTORS AFFECTING THE BUILDING'S ACOUSTICS

One of the most critical aspects affecting a building's acoustics is reverberation. Other characteristics that affect reverberation include loudness, focussing, echelon effect, unwanted noise, and resonance.

If a regular structure in the hall, such as a flight of stairs or a railway asset, the sound created in front of it may produce a musical note due to regular successive echoes of sound reaching the observer. The echelon effect is a term used to describe this type of phenomenon. If the frequency of this note is within the audible range, the listeners will only hear this note.  

To avoid:

Cover such surfaces with sound-absorbing materials to avoid the echelon effect.