Any studio should have a delay. Once he was the simplest successor to a tape reverb (tape recorder, the tape on which is connected in a ring). Then, modulation controllers appeared in it, with the help of which it became possible to create various effects – from echo and duplication to chorus, flanger, artificial double track, vibrato and phase shift.
The input signal passes through the “gain” control (usually there is also a measuring system for fine level control). It is required to precisely set the signal level so that there is no noise and distortion. After this, the signal is separated, part of it goes directly to the output controller “mix”, where it is combined with the delayed signal.
At the input of the delay line is an analog-to-digital converter. Here, the signal is converted into a sequence of numbers, which then enter the memory. Writing to and reading from memory in most devices is controlled by a microprocessor, which in turn is controlled by the “range” control. Thus, a larger or smaller part of the memory is connected to the work (depending on the amount of delay that must be received). A timer that sets the sampling rate and a modulation generator also interact with the circuit. By changing the sampling rate, you can adjust the delay time (usually more than 2: 1). Using the modulation control, a cyclical change in the signal height is established with the speed and depth that are required to create the effects of “chorus”, “flanger”, “vibrato”. The modulated waveform is usually triangular or sinusoidal. Both forms give a soft sweep, but it is believed that a sinusoidal waveform is preferred.
The signal in digital form is recalled from the memory and passes through a digital-to-analog converter (DAC), where it again becomes analog and is mixed with an uncontrolled signal.
There is one more parameter – feedback (feedback). The feedback regulator sends part of the signal from the output back to the delay line, thereby obtaining a repeating echo. The feedback value should be less than unity (the whole signal), otherwise each new echo will increase in level, and not fade out. Uncontrollable howling may result. Some models have a phase switch, which, with a very short decay time, gives the signal a subtle change in tone (in particular, in the flanger effects). Depending on the position of the switch, the flanger reinforces or crosses out (subtracts) a part of the changes.
The simplest effect is a single delay. The depth and modulation speed controls, as well as the feedback control should be set to a minimum. The range knob determines the delay time. Then, using the fine handle, you can select such a delay time so that it corresponds to the tempo of the song (from 20 ms – short echo – to a delay of 1 or more seconds). In order for such a single repetition to turn into a real repeating echo, you need to adjust the feedback knob. The output signal is fed back to the delay line; attenuation time is set by the feedback regulator.
The chorus effect has a distinctive sound and is often used to process guitars, basses and keyboards. To achieve this effect, you need to set the delay time to several tens of milliseconds and introduce a 3 Hz modulation. For best results, direct and delayed signals should be mixed in equal proportions. The modulation depth should be small, otherwise the effect will sound rough.
This effect got its name because it gives the impression of several instruments playing the same note together. He makes a temporary and high-altitude difference, which is always there when several people try to play the same thing. In addition, the “chorus” effect allows you to make the sound of electronic instruments more natural. The fact is that the synthesized signals have a clearly structured waveform, which does not exist in natural sounds. With the help of chorus, you can make a cheap electric organ sound just like a real one (pipe organ).
If you further reduce the delay (to a few milliseconds) and remove the unprocessed signal from the mix (using the “mix” knob), you get a real high-altitude vibrato, which can be used to process instruments and vocals. If you return the raw signal, you get an effect similar to a phase shift; if you add a little feedback to this, you get a flanger. The flanger effect, like many others, is difficult to describe in words, but it is instantly recognizable by ear. This effect was widely used in music of the 60s and early 70s as a “psychedelic” treatment for rock songs.
Flanger sounds better if the modulation frequency is small (about one second), and the modulation depth is slightly greater than for the chorus. Changing the delay time will affect the pitch and harmonics in such a way that the flanger peaks and switching the feedback phase can give new interesting sound solutions.