Ecasound Delay Wet and Dry Balance Parameter

This article provides a concise overview of how Ecasound handles delay effects, specifically detailing the parameter responsible for balancing the wet (processed) and dry (unprocessed) signals. While some of Ecasound's built-in time-based operators output fixed signal levels, its primary multi-tap delay effect features a dedicated percentage-based mix parameter. Understanding how to configure this parameter allows you to precisely dial in anything from subtle ambient space to fully saturated delayed soundscapes.

The Built-In Delay Effect Operator

In Ecasound, the built-in delay effect that explicitly features a dry and wet balance control is the multi-tap delay operator, invoked via the -etd chain operator.

The syntax for the operator is:

-etd:delay_time,surround_mode,number_of_delays,mix-%

The fourth parameter, mix-%, directly controls the wet and dry balance of the delay effect.

Understanding the `mix-%` Parameter

The mix-% parameter represents the percentage of the wet (delayed) signal mixed into the final output relative to the original dry signal:

0%: Produces a completely dry signal with no audible delay effect.
50%: Produces an even, balanced blend of the direct source audio and the delayed repeats.
100%: Produces a fully wet signal, muting the initial dry audio and outputting only the delay taps.

Operator Parameters Breakdown

To configure the delay properly, you must supply all parameters in order:

delay_time: The base delay duration measured in milliseconds.
surround_mode: A binary flag (0 for standard stereo/mono, 1 for inverted surround phase).
number_of_delays: The number of repeated taps generated by the delay line.
mix-%: The wet/dry balance percentage (from 0 to 100).

Usage Example

To apply a 300-millisecond delay with 4 taps and a 35% wet balance on an input file, execute:

ecasound -i:input.wav -o:output.wav -etd:300,0,4,35

Controlling Wet/Dry on the Standard Echo (`-ete`)

Ecasound also includes a simpler echo operator, -ete:delay_time,surround_mode,feedback. Unlike -etd, the -ete operator does not have an integrated wet/dry balance parameter; it continuously mixes the delayed feedback into the direct path at unity gain.

If you require dry/wet control when using -ete, you must split the audio across two parallel chains inside Ecasound: one chain processing the dry signal with an amplitude modifier (-ea), and a second chain hosting the -ete effect, adjusting their relative balance via each chain's individual gain controls.