Echo, Reverb, Delay 的分別

echo回音
回音是指比直接音慢至少50毫秒的反射音，而且它的音量也比殘響大聲。

Reverb 殘響
音源停止發音後，室內仍然存在的聲音叫殘響，很多人誤會為回音echo，殘響時間的定義是讓聲音音量衰退為千分之一所需的時間稱為殘響時間，換句話來說是音壓電平減低60db的時間。
所有室內房間都有殘響，只是殘響時間不同，室內音響環境就不同。

Delay 延緩是用信號切換功能來延緩輸出信號，是可控制的信號。

識別方法:
簡單來說，山洞中…我我我我我.... 的聲音，就是echo
concert hall或教堂神父的聲音，就是reverb
delay effect, 一般來說，不是自然環境可以有的，是用信號切換功能做出來的。

DEFINITION

Delay is defined as the splitting of a signal into separate components, the slowing of one of these split signals, and its subsequent re-introduction into the original signal.

Echo is defined as a delay of approximately 35 ms. in which the regenerations are evenly spaced and in which the release portion of the sound envelope is even as well. This is also sometimes referred to as Early Reflections.

Reverb is defined as a delay less that 35 ms. in which the regenerations are randomly dispersed and in which the release portion of the sound envelope is random as well. This is also sometimes referred to as Later Reflections.