Saturday, 21 November 2009


Reverb is a prolongation of a sound after it has decayed away (Dying away).

Many thousands of reflections which become more dense as time goes on and then they decay away.

A reverb unit is a unit which produces the acoustics of an environment such as a large room, cathedral, sewer etc.

Reverb is anything under 500ms.

Delay is anything over 500ms.

Parameters for Digital Reverb

The following controls are essential for creating an acoustic environment;

Pre-Delay is the time taken for the reverb to start once the direct sound has ceased. (When the reverb starts)

RT60 Reverb Time (Reverb Time To -60dB, To Decay Away) is how long the reverb lasts until it decays away to -60dB (The longer the RT60 the bigger the acoustic environment is.

HF Decay (High Frequency Decay) HF Decay is how long the high frequency content takes to decay away.

This works in conjunction with the RT60 reverb time. The lower the HF Decay time is, helps to create a warmer sound on the reverb. Also gives the impression that there are objects in the room.

LF Decay (Low Frequency Decay) LF Decay is how long the low frequency content takes to decay away.

This works in conjunction with the RT60 reverb time. The lower the LF Decay time is, the more of a metallic sounding reverb.

X-Over/Cross Over is where the high frequency (HF) and low frequency (LF) content are separated. (Centre frequency/Like a filter)

Density controls the amount of spacing between the reflections.

Diffusion controls the amount of dampening to the reflections, Just like introducing objects to a room, the higher the diffusion the more objects that are in the room dampening the sound.

Size works in conjunction with the RT60 reverb time. The bigger the room or acoustic environment the bigger the RT60 reverb time is going to be.

Types of Reverb

There are two types of reverb;

1) Mechanical Reverb (Created mechanically by a device).

2) Digital Reverb (Created digitally).

Mechanical Reverb Device's
Reverb Chamber
A reverb chamber can be of any size, You will place 2 microphones equal distance and equal height from the sound source and record the reverberation from that environment.

Spring Reverb
A spring reverb is when a sound is transformed through the spring's, this creates an artificial environment.

You do not have any controls over the reverb time, etc.

Original spring reverb units have a nice warm sound.

Plate Reverb (EMT Plate Reverb) is a big unit which can come in many shapes and sizes.
Inside the unit is 2 large plates, a speaker and 2 pickup's (Microphones).

It basically records the acoustics of a sound when it is played through the box environment.

You have no control over any parameters. Original plate reverb units have a nice warm sound.
Digital Reverb Unit's

Basic Digital Reverb Programs Found On Most Units;
1) Hall Reverb (Different hall size's)
2) Room Reverb (Different room size's)
3) Gated Reverb (Reverb Gated)
4) Reverse Reverb (Swelling delay)

Various Programs can be created by adjusting the paramaters

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