Reverb is one of the most widely used effects in music. You might not know it, but you actually hear reverb every day, everywhere you go. Reverb or ‘reverberation’ is the result of the sound waves reflecting on the walls of a room.
We usually hear not only the direct sound from the sound source (for example a speaker) but also the sound that is reflected from the walls. A reflected sound wave arrives to our ears a little later and a little weaker than the direct sound.
Whereas an echo implies distinct version of the sound with a large delay time, the delay time of a reverb is typically short, and the ear can not really discriminate between the original sound and each reflection.
In reverb, we hear the effect created by the multitude of reflections: the sound reflects against different surfaces at different distances in the room, coming back at many different delay times.
Reverb actually adds the sound of a room. The parameters of the reverb effect can be tweaked in order to simulate a small room or a bigger room, with many different characteristics.
In a total mix, reverb takes up a lot of ‘room’ as well. It is an extremely powerful effect for the violin, but should definitely be used with care.
In reverb, the arriving sound waves increase over time. For a short period after the original sound, our ears can perceive a set of well defined and directional sound waves.
These sound waves are called early reflection and they are directly related to the shape, size and other characteristics of the room and to the distance between the listener and the sound source. After the early reflections the reflected wave sounds arriving at the listener increase rapidly.
These arriving sounds seem random and you cannot relate them to the shape (or other characteristics) of the room.
An other characteristic of the reverb is the correlation of the signal that reaches your ears. In order to have an effect that gives the listener the real feeling of a big room the sound at each ear has to be somewhat incoherent.
Real concert rooms have the ceiling very high so the first reflected sound comes from the walls.
Since the distance between a listener and the walls around him are different, the sound that reaches each ear is slightly different as well.
A first parameter that is used with the reverb is the reverberation time. The reverb time is the time it takes for the sound pressure intensity to decay to 1/1000 of its original amplitude.
As a simple rule, it is recommended to use short delay times for fast fiddling, and a longer reverb times for a slow electric violin piece.
Other important reverb parameters are the room surface and the room type. The surface determines to which extent, and at which frequencies, the original sound is reflected.
Any accoustic violin player knows that carpet and curtains can have an enormous impact on ‘room sound’. The human body is also a highly absorptive material.
Many digital reverb units offer the choice for a ‘room type’. Plate reverb, hall reverbs or any other type: the actual choice can only be made by experimentation.
Two other common parameters are predelay and reverb decay. Large rooms naturally have a longer predelay time than small rooms. Predelay may be smaller than 30 ms to simulate a small size room, and may be up to 100 ms for an enormous hall. ‘Decay’ represents the period of time in which the sound is still heard after the input stops.
For a very useful overview check this article on reverb parameters.
Using a reverb effect for your violin allows you to make your sound seem like you are playing in whatever kind of space you would like.
For instance, you could set your reverb effect to sound as if you where playing in your bathroom, or a concert hall, whichever suits you best.
Good reverberation units allow you to control all essential parameters, such as the time before the first reflection returns, the number of reflections, the complexity of each reflection, and so on.
The first reverb effect was achieved by approximating the effect artificially. Echo chambers were constructed to simulate reverb, big hanging metallic plates and electromagnetic transducers were used and other inventions with the sole purpose of simulating the natural sound of reverb.
The new era introduced the digital reverberators. Reverb is achieved using micro-chips.The best reverb is obtained through separate modular effect processors used in special studio reverberators.
Modern digital reverbarators offer a wide area of programs, presets which simulate real conditions such as concert hall, room, live, chamber, gate, invert, and others.