Delay

Makes a Delay effect in a selected part of an audio file.

Parameter	Description
Duration	Maximal amplitude in db, which is considered as silence, from -92 db to 0.
Mix Depth	Time of trim fade, in ms.
Feed Back Gain	The type of trim. Can be one of the following types: trim from left, right or from both sides of trim level.

Tip:

See also: Apply a Special Effect or Filter
Delay is an echo effect that replays what you have played one or more times after a period of time. It's something like the echoes you might hear shouting against a wall.

You can use this function to create single echoes, as well as a number of other effects. Delays of 35 milliseconds (ms) or more will be perceived as discrete echoes, while those falling within the 35-15 ms range can be used to create a simple chorus or flanging effect. (These effects will not be as effective as the actual chorus or flanging effects, as the delay settings will be fixed and will not change over time).
For more information about delay effect see: http://www.harmony-central.com/Effects/Articles/Delay