MASELEC MDS-2
High Frequency Limiter
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OPERATION
M-S………………….. Switches the side chain inputs to M-S (sum and difference).
LINK…………………. Hard links the side chains after the time constants.
ON…………………… This control enables the high frequency limiter.
FAST………………… This control makes the release time shorter.
HF THRESHOLD…… Adjust this control to set the amount of high frequency limiting.
BYPASS………………Galvanic bypass of the unit. The meters show, with reduced
intensity, the gain reduction that would occur if the unit was
not in bypass
The meters show the amount of actual gain reduction (no hold times are incorporated).
Longer release times will be noticed for:
•
Frequent limiting over longer time periods
•
Large amount of limiting
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 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 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 will reduce HF limiting from ‘stereo’ signals whilst retaining the
limiting on centre signals.
The M-S mode does not affect the actual audio path!
