Space-based effectors for spreading sounds such as reverb, echo, and delay create the size and condition of the space, etc., and create an “illusion” in the sense of hearing. A space system effector is an effector that simulates the space in which the sound sounds literally by adding various reverberations. The sound changes depending on how you use the space system effector.

This time, I will introduce the differences between reverb, echo, and delay.

■ What is reverb?
Reverbs combine more complex delays to create reverberation in space. Simply put, reverb is a collection of delays. The reverberation that we usually listen to is considered to be a collection of more complex delays.

Even if you are in a room that is simply a square with nothing, your voice and the noise you make will come with reverberation with innumerable different delay times. And, the reverberation sound changes the sound quality and length depending on the size and shape of the room, and the material of the wall and the floor.

The reverberation sound bounces back to the wall or floor and reaches the early reflections that reach your ear directly (early reflection) and hit many places many times and finally bounces back to your ear. There is a reverberation.

Creating reverberation like this was the work of designers and architects before reverberation as an electrical effector appeared. They decided on the material and the angle of the floor and the wall to obtain the best reverberation while repeating various trial and error.

Even in the age of electronic recording records, this situation did not change for some time. Once the recording engineer had picked up the mic, he sent it to a very long reverberation room speaker, called the echo room, and controlled the reverb by picking it up again with the mic.

■ What is the echo?
What people, in general, say echo and immediately come to mind is what is called “one reverberating in the mountains”. An echo is a kind of effector that produces an effect that sounds like “one reverberating in the mountains”. Electrical or electronic simulation of the natural phenomenon is an effector called an echo.

The first electrically simulated effect that delays the sound is tape echo. Originally, it used the time difference between the recording head and playback head of the open reel tape deck, but it has been completed as an easy-to-use effector. Roland Space Echo RE-201 is a famous model of tape echo.

■ What is the delay?
A delay is a type of spatial effector that simulates with echoes. When you yell “Hello” toward the mountain far from the summit, a voice “Hello” will be returned from the other side for a while.

The speed of the sound is about 340m per second at room temperature, so if the distance to the next mountain is 340m, it will take 1 second until your voice reaches the other mountain, another 1 second until it bounces and you can hear your ear. It sounds like a delay of seconds.

Besides, in places where you can get a very clear wave, it is repeated again and again that the voice you return once is reflected in your standing mountain, and reciprocated between the mountains again. And you hear the voice “Hello” over and over again, gradually lowering the volume at regular intervals. This is called a repeat delay.

There are many cases where the voice bounces back and there is not only one mountain. So, in your ears, you will hear the voices of different delay times reflected in different mountains at different distances, “Hello”. This is an effect called tap delay.

There are two main types of delay effects: analog delay and digital delay.

Analog delay is an analog delay that has been developed as a maintenance-free delay for tape echo that takes time for maintenance.

In analog delay, the circuit delaying the sound called BBD element is connected in a row, and long delay is created like a bucket relay.

Digital delays store sound in memory instead of tape and take advantage of the time difference between the record and play heads. The input signal is first converted to a digital signal of 0 and 1 through a circuit called an AD converter and written to memory. And it is the principle which reads the data written in the memory according to the decided delay time, returns it to an audio signal through the DA converter, and outputs it.

The principle itself is common to all digital effectors, and in a sense, it can be said that all digital effectors are created by applying the digital delay principle.

■ The difference between each
I will briefly introduce each difference.

◆ Echo and reverb
You might know that echo is often used in karaoke boxes to “put more echo”. Karaoke echo is active every night in the karaoke box. Reverb is an effect that makes a sound like a reverberation in a certain space system. Depending on the setting of “size of space”, you can feel as if you are singing in a large concert hall because you feel like you are singing in a small karaoke box.

◆ Echo and delay
The echo and delay are similar effects. Both of these are effects that reverberate the sound volume down at regular intervals. The echoes are those that shorten the reverberation interval of this “one reverberating in the mountains”. The delay is what lengthened the reverberation interval.

Echoes are mainly used for vocal voices, etc. Delays are not used primarily for vocal sounds but are used as effects for instruments such as electric guitars.

◆ Delay and reverb
The delay has a delay effect as the name implies. Reverb is a pseudo reproduction of the reverberation occurring indoors. Reverb is just a reverberant, while the delay is after the original sound, then the sound is delayed at regular intervals to follow.