Audiences normally have no knowledge of the audio system in between the sound sources and their ears. For their assessment of sound quality - the degree of satisfaction of their individual hearing experience - they see the sound source and the audio system as one entity. For performances stored on media carriers (eg. CD, DVD, USB stick, hard disk), the play-out (‘HiFi’) system is recognised by consumers as a seperate system affecting sound quality, but the system used for producing the content (eg. music studio equipment) is not recognised separately.
Normally only ‘audio professionals’ distinguish the full audio system from the sound source(s) as a separate entity affecting audio quality. Audio professionals include product manufacturers engineers, system designers and sound engineers operating audio systems.
Most audio professionals will agree that the Performance of a system should be as high as possible, offering low noise floors, low distortion, high output, high bandwidth etc.
On the Response of systems however, the opinion of audio professionals differ. For products specially designed for a genre of applications, manufacturers and system designers sometimes apply fixed Response processes in systems because they are generally required for that particular application genre - eg. ‘warm’ sounding head amps for pop music. For products and systems designed to serve a variety of applications, the Response processes are offered as variable parameters, transferring the decision to use them - and in what degree - to the sound engineer operating the audio system.
With the increasing complexity of projects, and also the increased focus of investors and artists on a system’s sound quality and the sound engineer’s creativity, there is an increasing demand for a systems with a natural sound default response - maximally respecting the ‘natural’ sound characteristics of the sound source through a high system Performance to retain the sonic qualities of the audio signal as it was generated by the sound source as much as possible. All system Response processes are then available as colouring tools - allowing sound engineers to freely ‘shape’ the system’s sound to suit the project’s creative goals.
In general, for manufacturers and system designers it is more costly to offer variable Response processes than fixed Response processes because of the extra connectivity and user interface facilities required for variable processes. If the ‘warm sounding pre-amp’ is offered to the sound engineer as a variable process, it needs additional switching and control circuitry (either analogue or digital), and a user interface (eg. knobs or a touch screen GUI) to control them - which is more costly than offering the process in a fixed form. With the increased processing power of digital mixing consoles, many Response processes are now offered to the sound engineer as ‘plugin’ units, available to be inserted in any signal chain in the system. In general, digital (networked) systems offer much more variability of the process parameters compared to analogue systems, but there are still many differences in variability between digital systems as a result of design philosophy and application genre target.
Using the Performance and Response concept, sound systems can be categorized as ‘coloured sound’ and ‘natural sound’ systems. In the below figures, the amount of fixed and variable processing is represented by the size of the Response process blocks: