Operation - Maselec MPL-2 Quick Start Manual

INPUT GAIN........ 0dB to 10dB. Adjust the gain to achieve desired amount of limiting.
THRESHOLD....... +14dBu to +22dBu. The limiter threshold is normally adjusted to just below
(limiter) maximum peak operating level. Further adjustments should not be necessary.
Note: This control relates to peak programme level. Do not use sine waves
(steady tones) to adjust, instead use programmes. You could increase the input
gain to make it easier find the threshold that stops 'overs' and then re-adjust the
gain after the threshold has been set.
HARD................. This control changes the limiter character to:
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The 'HARD' mode is particularly useful for percussive programmes and should be
used with care for softer, low- to mid-frequency programmes.
HF THRESHOLD.. Adjust this control to set the amount of high frequency limiting. The limiter setting
affects this control: The HF threshold is relative to the limiter threshold as if the
two controls are in series (also when the limiter is off).
M-S.................... Switches the side-chain of the HF limiter to M-S mode (the actual audio-path is
not affected). This function can be used to 'zoom in' on high frequencies in the
centre of the stereo image. With this control in the M-S position, signals that are
either in the centre (mono) or 180 deg. out of phase have a 6 dB lower threshold
than signals that are panned extreme left or right. The M-S mode can reduce mis-
triggering of the HF limiter.
The meters show the amount of actual gain reduction (no hold times are incorporated). Longer
release times will be noticed for:
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Note: 0 dB indicates 'above threshold'.
Optimum reduction of peaks is maintained for extensive variations of programme materials. When
longer release times are noticed, additional reduction of short duration peaks will still only cause
short, programme dependent, release times. The result is predictable and consistent performance
over a wide dynamic range.
The 'hard' position should be used for dynamic, percussive programmes. Care should be taken with
softer, less dynamic, low frequency programmes, as this option could cause increased coloration.
The HF limiter has a maximum range of 11dB starting at approximately 2kHz.
The attack time is both programme dependent and non-linear relative to the amount of limiting taking
place. It is long for small amounts of HF limiting (>20msec) and becomes progressively faster for
more limiting (<1msec). This acts as a barrier for HF limiting near or just above the threshold and
increases selectivity. The result is a natural balance of transient and sustained high frequencies.
The M-S control will further increase the selectivity for programmes with excessive treble in the
centre of the stereo image. This is normally the case when de-essing vocals.
Switching to M-S reduces HF limiting on 'stereo' signals whilst retaining the limiting on centre signals.
Note: The actual audio path is not M-S processed.

OPERATION

Harder knee
Shorter release time
Slightly more aggressive increase of loudness
Low frequency signals
Frequent limiting over longer time periods
Large amount of limiting
MASELEC MPL-2
Peak & High Frequency Limiter
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