Equalising A System; Preparing For Equalisation; Equalisation Using An Rta - Klark Teknik Square One Graphic Operator's Manual

Equalising a system

Equalising a system
As discussed before, the fundamental benefits of equalisation are:
• Improved intelligibility and natural sound of the sound system.
• An increase in the gain available in the system before feedback.
In some circumstances, it may not be possible to achieve a natural sounding system that is completely
intelligible due to poor acoustics or high levels of background noise. In such cases, a compromise must be
struck by the engineer depending upon the use to which the system will be put. It may be argued that in the
case of a vocalist, intelligibility must be sought at all costs. However, for dance music reproduction a more
natural approach, with no real concern for intelligibility of the individual lyrics, may be preferred.
Please remember, the equaliser is not a 'cure all' device and will not solve the problems of a poor sound
system, installation or venue acoustics but, when used carefully, can bring out significant improvements in
the quality of reproduction of a system.

Preparing for equalisation

Before starting to equalise the system, it is worthwhile checking that the system is performing correctly.
Listening to the system without any equalisation may reveal underlying distortion or artefacts of the room,
for example, lengthy reverberation, which may need to be rectified before trying to equalise the room.
It may also be worthwhile using a sine tone sweep so that problems at certain frequencies, which may not be
immediately noticeable with pink noise, can be detected and corrected before equalisation. Especially, check
the system's crossover points as these may reveal problems with the system. Note that poor coverage
cannot be rectified through the use of equalisation.
When you are satisfied with the basic system performance, equalisation can begin.

Equalisation using an RTA

The measurement microphone should, ideally, have a flat response or be calibrated to the RTA and placed in
a sensible position where it will not be affected by nearby objects that may interfere with the local acoustics,
such as within one metre of a rear or side wall, or in a balcony opening.
Using the RTA and a pink noise source, adjust the level of the frequency bands on the graphic equaliser
inversely to that shown on the RTA display. Do it so that the peaks in frequency response are reduced to the
level of the other bands and, conversely, the deficient bands are increased. You will need to perform the test
at a reasonable level approaching normal usage volume so that the equalisation can take into account the
response of the loudspeakers at normal operating level (versus low level). It may also be desirable to take
measurements at points throughout the area. Although it may not be possible to get perfect equalisation
throughout an entire area, it may be preferable to obtain a good equalisation of the whole area rather than a
perfect equalisation at a single point with poor performance at all other points. A compromise may need to
be made in an effort to equalise the sound for the whole area rather than just the centre FOH position.
20 Square ONE Graphic