ER-301/Delay

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Applications

  • Simulating an echo (slapback), or use multiple delays to add a sense of space similar to a simple reverb.
  • Use very small modulating delays (<50ms) to get comb filtering, flanging and chorus-like effects.
  • Delay on Wikipedia

Description

A delay line with feedback and wet/dry controls. This delay line is not interpolated, so actual delay times are rounded to the nearest sample.

Clicks and pops during abrupt changes to the delay time are prevented by periodically cross-fading between two play heads and only moving the silenced play head to the new delay time. This cross-fade occurs at a rate of approximately 40Hz, which means that the effective delay time is only updated once every 25ms.

Special Menu Operations

Maximum Delay Time

This menu setting allows you to expand (or shrink) the pre-allocated buffer for the delay line. The size of this pre-allocated buffer determines the maximum delay time accessible in real-time via the delay parameter.

Maximum-Delay-Time.png

Delay units are created with a default buffer length of 1s.

Parameters

delay

Control Type Has Sub-chain? Sub-chain Parameters Fader Scale
Gain/Bias yes gain (-3 to 3)

bias (0s to Ns)

linear time


This parameter dictates the length of the delay line. In other words, how long it takes for a sound to pass from the input to the output of the Delay unit. The maximum value of this parameter (N) is determined by the Maximum Delay Time setting in the unit's menu.

When this unit is placed in a stereo chain, then the delay parameter is split into separate parameters for the left and right channels.

feedback

Control Type Has Sub-chain? Sub-chain Parameters Fader Scale
Gain/Bias yes gain (-3 to 3)

bias (, -36dB to 0dB)

logarithmic


This value determines how much of the audio in the delay line to mix with the delay's input. A value of 0dB means that the old and new are summed together as-is and will eventually cause the contents of the delay line to grow so loud that it will clip when it arrives at the DAC. A value of means that the new material completely replaces the old material in the delay line. Anything less than 0dB will cause the old material to slowly fade away with each (delayed) repeat. The following graph summarizes the number of repeats required to fade to 10% of the original captured amplitude vs the feedback amount:

Repeats-vs-feedback.png

wet

Control Type Has Sub-chain? Sub-chain Parameters Fader Scale
Gain/Bias yes gain (-3 to 3)

bias (0 to 1)

linear


This parameter controls the amount of the input signal and of the affected signal which is passed to the output. A value of 1 (i.e. 100% wet) means you will only hear the affected signal. A value of 0 (i.e. 100% dry) means you will only hear the signal received at the unit's input. However, the cross-fade curve is not linear but rather lifted to counteract the tendency for loudness to dip in the center of a linear cross-fade curve. The actual cross-fade curve looks like this:

Cross-fade.png