This is achieved by playing back a burst (impulse) of a full range of frequencies within the space and recording it. The impulse responses or IRs are captured by recording how a space responds to a full range of frequencies (typically 20Hz to 20,000Hz). It could be described as an acoustic ‘photograph’, where, instead of capturing a space visually, it is captured aurally. Impulse responses allow us to capture and store the acoustic characteristics of a space (or piece of sound altering equipment). Over the recent years, convolution has been widely used to recreate the reverberation of spaces, the sound of hardware units (reverb units, equalisers, tape machines, guitar amps, etc) and in creative sound design.
Convolution of spectra means that each point in the discrete frequency spectrum of input a is convolved with every point in the spectrum b. It is different from the plain multiplication of two sounds where a single sample of the first sound is multiplied by the corresponding single sample of a second sound.Ĭurtis Roads ( The Computer Music Tutorial) describes convolution as:Ĭonvolution of two audio signals is equivalent to filtering the spectrum of one sound by the spectrum of another sound.
What is convolution?Ĭonvolution is the process where a single sample of a sound is multiplied by every sample of another sound. This article is a description of the general concepts behind recording good impulse responses and should be easily adaptable to any convolution/de-convolution tool. This not only helps ‘personalise’ your mixes, but is extremely useful in post-production and in the design of new sounds.Įach of the above mentioned plugins need slightly different techniques for creating a custom library of impulse responses. They are usually packaged with large and useful libraries of impulse responses (more on what all this means below), but what makes them really powerful is the fact that it is quite easy to record and use your own impulse responses. Some of the most common ones include Audio Ease Altiverb, Logic’s Space Designer, Avid TL Space, Waves IR-1 and McDsp Revolver.
With growing computing power over the last decade, convolution plugins have become commonplace.
0 kommentar(er)
