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5.3.3 The Muffling Effect Of A Compressor
Quite often, compressors are sometimes accused of muffling the sound, whilst at the same time reducing
the dynamics. This fact should be investigated further. Bass frequencies contain most of the energy within
music and therefore cause the compressor to reduce the overall dynamics. If the music also contains high
frequencies along with the bass frequencies, these are also reduced in level. This is the reason why: in an
extremely compressed recording of drums, the cymbals and high-hats are acoustically swamped by the
sound of the snare or the bass drum. The same effect is experienced when processing reverberated or
ambient sounds. The solution commonly used to this basic problem is either to reduce the compression ratio
or to slow down the attack time, so that the increasing high frequency transients pass through the compressor
unhindered before the compressor takes effect.
The COMPOSER PRO MDX2200 offers a solution to this problem that is by much more elegant. The SC Filter
switch allows you to activate a high-pass filter in the control signal path of the compressor. This filter makes
sure that midrange and treble range frequencies are taken into account to a greater extent, and that a low-
frequency signal triggers less compression than a midrange/treble signal of comparable level. A major advan-
tage of this design can be seen in the fact that the frequency response of the overall signal is not modified
below the threshold adjusted with the Threshold control.
In pop music the dynamics of both kick drum and bass guitar are usually processed individually. The side-
chain filter is therefore ideally suited to apply overall compression in the mix-down, to compress the music
while increasing its loudness, but without having to accept the drawbacks described above.
Please note that we offer a whole series of high-grade equalizers and enhancers/exciters, which are perfect
tools to give any dynamics-processed signal the finishing acoustic touch. Please ask for detailed information!
5.4 Peak Limiter section
As a section of its own and independent of the remaining control functions, the peak limiter enables you to
limit the maximum peak level on the COMPOSER PROs output. It has been designed for use in combination
with the compressor section. Independently of all compressor functions, you can protect subsequent devices
against signal peaks, short-time overload and excess modulation (radio stations, etc.).
Output
Input
Peak Limiting
Program Limiting
Release
Threshold
t/ms
Level
20 ms
10
20
30
5 ms
approx. 1 s
Fig. 5.3: IGC characteristic of the limiter section
The diagram illustrates the functioning of the IGC limiter. The solid graph represents the output signal, while
the dashed graph above shows the input signal response. The areas between the graphs represent the
amount of gain reduction (bright areas are clipping areas, i.e. signal peaks are radically cut off, dark areas
show the effect of the program limiter). The limiter is activated when the adjusted threshold is exceeded for
more than 20 ms, so as to limit audible clipping to a very short moment. About 1 s after the signals has
dropped below the threshold again, the reduction is set to 0 dB, so that input and output signals are identical
again (unity gain).
5. APPLICATIONS
