In the world of professional audio one might assume that distortion is the last thing an engineer would want to be present in his audio recordings and to an extent this is true. The fact is that some genres of music actually require distortion and if used tastefully can produce a smooth and steady guitar sound or can be used to add a special effect to a vocal track to enhance the dramatic effect the performer might be looking for. The truth is that distortion is a common and widely used effect in audio production for music, commercials and movies.
Distortion does just what its name implies, it distorts an incoming audio signal by driving the input level higher than normal. Most distortion effects will come in the form of a stomp box or will be grouped with other effects in a rack system. Distortion can also be used in the form of a software plug in for digital audio workstations where there are no physical hardware systems. Distortion has basic and easy to use features and there are literally hundreds of manufacturers that create these distortion units. Each unit may have its own color and tone features specific to the company that creates them.
Distortion has three basic control systems to shape and contour the desired effect an artist or performer may desire and those control parameters are usually called “Drive”, “Tone” and “Level”. Some companies that create this effect might use different terms to describe these control parameters but the result is usually the same across the board.
The drive control will be used to set the amount of distortion the incoming audio signal will receive and can be set to a very low and subtle effect used in blues music or soft rock on a guitar signal to screaming overtones and feed back used in heavy metal and harder Djent styles of music. The difference is in how high or low the drive setting is pushed to create the desired effect and will cause a noticeable difference in sound quality in small increments along the setting range.
The tone setting will create a low or bass sound frequency that can be slightly muddy at lower settings or crisp high frequency sounds can be attained at the high settings that allow high frequencies to pass along the signal chain to the output of an amplifier or digital audio workstation monitor system.
The level is the setting that allows a certain amount of gain to pass to the output of the distortion unit and controls the output volume of the effected signal. This control of the level is useful when the drive control has been set to a high position but the audio engineer does not want the final result to clip the main outputs and can smooth out the harshness that a distortion effect can cause when used at high decibel levels.
A distortion effect can be used to change the entire audio input signal or can be used as a side chain effect that allows the original dry audio signal to be blended with the distortion signal creating a combination of both signals at the final output stage of the effects chain. This can be useful for creating a smoother and tone rich audio signal. Distortion is usually the first effect in an effect chain and is enhanced with other effects such as compression and equalization effects to round out the sound and to remove any harsh tones that might cause listener fatigue. Some rack systems that contain several effects will allow the user to set up a specific order of effects to create a simple preset that can be recalled later to save programming time.