Equalising A System - Klark Teknik DN370 Operator's Manual

Table of Contents

As discussed before, the benefits of equalisation are fundamentally:-

To improve the intelligibility and natural sound of the sound system.

To increase 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 these cases, a compromise must be struck by the engineer depending upon the

use to which the system will be put. It may be arguable that in the case of a vocalist, intelligibility must be sought at all costs. In

the case of dance music reproduction, however, it may be felt that the material should be reproduced naturally with no real

concern for intelligibility of the individual lyrics.

Before starting to equalise the system, it is worth checking that it is performing correctly. Listening to the system without any

equalisation may reveal underlying distortion or artefacts of the room (e.g. lengthy reverberation) that may need to be rectified

before trying to equalise the room. It may also be worth using a sine tone sweep so that problems at certain frequencies that may

not be immediately noticeable with pink noise can be detected and corrected before equalisation. Check, especially, the

crossover points of the system which may reveal problems with the system. Note that poor coverage cannot be rectified through

the use of equalisation.

The measurement microphone should ideally have a flat response or be calibrated to the analyser and placed in a sensible

position where it will not be affected by nearby objects that may interfere with the local acoustics.

Using the Real Time Analyser and a pink noise source, adjust the level of the frequency bands on the graphic inversely to that

shown on the RTA display so that the peaks in frequency response are reduced to the level of the other bands and similarly, 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 (vs. low level). It may also be

desirable to take measurements at points throughout the area. It may not be possible to get perfect equalisation throughout an

entire area but it may be preferable to obtain a good equalisation of the whole area rather than a perfect equalisation at a single

point and 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.

EQUALISER

PINK NOISE

When equalising the room, bear in mind the effect upon the electronics and mechanics of the system caused by the equalisation

process. If excessive equalisation is required at certain bands, consider the effect upon amplifier headroom and loudspeaker

driver excursion that will result. It may not be possible to produce the response required with the limitations of the system.

Excessive equalisation should act as a warning that there may be an underlying problem that may need to be rectified first (e.g.

phase cancellation, blown drivers, etc...).

During the performance, the FOH or monitor engineer may want to have a microphone or solo signal feed for the RTA so that

feedback may be easily detected and rectified.

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.

CALIBRATED MEASUREMENT

MICROPHONE

abc

REAL TIME ANALYSER

370

Operators Manual -

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