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Virtual Mixing
Processing

DELAY (ECHO) and REVERB


Delay (or Echo) is when a sound repeats.  When the repeat takes place a long enough time from the original sound, you can hear a distinct echo.  However, if the repeat takes place a SHORT fraction of a second after the original sound, it will overlap and create an interesting hollowness due to the phase relationships between the original sound and the delayed one.  A discrete sound (one that is recognizable as the original) is an ECHO.

In a large room, the echoes that you would hear are broken up while the sound bounces around from wall to wall and ceiling to floor.  The echoes become so mushed together that they sound like a smooth “tail” rather than discrete individual repeats. Text Box:

The upper diagram shows someone speaking in a long hall.  The sound bounces off the opposite wall and returns to them as a discrete echo.


The lower diagram shows someone speaking in an irregularly shaped room.  The sound bounces off the opposite wall but rather than bouncing back to the speaker it bounces at an angle and any discrete echo is scattered into a long smooth sound called REVERB.

Some external reverb devices have been built from springs or large steel plates.  Some studios have dedicated “lively” sounding rooms with speakers and microphones that exist as “reverbs” that can be plugged into the console.