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COMPOSER PRO MDX2200
Output
Input
Peak Limiting
Program Limiting
Release
Threshold
t/ms
Level
20 ms
10 20 30
5 ms
approx. 1 s
Fig. 4.3: 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).
4.4.1 Initial settings for the peak limiter section
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Tab. 4.3: Initial settings for the peak limiter section
The THRESHOLD control of the Peak Limiter sets the threshold level, so that subsequent units are protected
from overloading. If the LIM comes on regularly or is on constantly, the OUTPUT control of the Compressor
section must be turned down, as this control sets the level of the signal, which is routed to the Peak Limiter
section.
If this technique leads to an undesired drop in the overall level, it is recommended that you increase the
compression: either, reduce the threshold level, or increase the compression ratio with the RATIO control. The
OUTPUT control will compensate for a renewed drop in level.
5. SPECIAL APPLICATIONS
5.1 Using the COMPOSER PRO for recording and cassette duplication
In the recording and duplication field the goal should always be to achieve an optimum recording level onto the
recording media. Too low or too high recording levels lead to side effects such as noise, distortion etc. In
mastering and multitrack recording, as well as in duplication, one should always take care to utilize the full
dynamic range of the tape recorder, DAT recorder etc. Principally, it is possible to control the recording level by
riding faders, which means with low level signals, the gain is increased, whereas the amplitude of high level
signal is reduced. It is obvious that this method is insufficient because, especially in live recordings, the
expected signal levels cannot be anticipated correctly. Especially with multitrack recordings, which are run
under hectic circumstances, the signal level of all channels cannot be monitored and controlled at the same
time. Generally, with manual control, it is not possible to achieve satisfying recording results.
An automatic gain control system achieves better and more constant results. Use the COMPOSER PRO by
starting with the initial settings, and use its dynamic control functions in order to be able to drive an analogue,
as well as a digital recording, up to the limit of its maximum dynamic range while remaining noise- and
distortion-free.
5. SPECIAL APPLICATIONS