Introduction to Music Production 5 – Delay
Delay, in its simplest form, is the act of causing a signal to play an increment in time after it is supposed to play. With a feedback loop, it creates the common echo effect, where each iteration is slightly quieter than the last. The higher the feedback, the longer the decay of echoes. You may also have options to set the speed of the iterations, and some devices may sync to beat increments.
Most delays (and many other effects) contain a knob labeled “Wet/Dry.” Up to 50%, the dry (unprocessed) signal will be louder than the processed signal. Above 50%, you may notice that the first iteration is actually louder than the dry signal. If you want to simply make a sound start late, without any echoes, set the wet/dry to 100% and the frequency as low as possible.
For all audio players below, you will hear the dry, unprocessed sound first, then the processed sound.
Here is an example of a simple delay with no feedback.
Here is an example of a simple delay with feedback.
More complex delay-based effects are achieved by various means of modulation.
Ping Pong – This effect is usually made up of two simple delays, each panned to opposite sides. The delay times may be changed so that it appears that the echoes are bouncing back and forth, not unlike a game of ping pong.
Flanger – an effect that mixes two (of the same) audio signals together, one signal delayed by a small and gradually changing period (time). The effect sounds like a sweep.
Phaser – a delay based effect that filters a signal by creating a series of peaks and troughs in the frequency spectrum. An LFO (Low Frequency Oscillator) may modulate the position of the peaks and troughs of the waveform so that they vary over time, creating a sweeping effect that is similar, but still obviously different, to flanging.
Chorus – a delay based effect that creates multiple instances of the same signal, but changes the pitch and initial attack times so it appears that multiple instruments are playing the same part. The pitch may be modulated over time using an LFO (Low Frequency Oscillator – slow changes).
The HAAS Effect – a psychoacoustic perception that helps create space in the center (stereo field) of a mix, creating a wider perception of a sound. In this concept, a simple delay is placed only on one side of a sound to postpone only that side between 10 and 80ms. Because of this difference, our ears perceive the sound as being very wide, and creates the perception of the instrument taking up a span of the stereo field. Eleanor Rigby by the Beatles uses the HAAS effect on the vocals.