Maselec MDS-2 Stereo De-esser  From Maselec

The Maselec MDS-2 is a High Frequency Limiter which is often used as a De-Esser.
It can also replace Acceleration Limiters for vinyl disk cutting.

The MDS-2 is a dual mono, linkable, high frequency limiter. It is housed in a 1U 19" rack mount alloy case. It is primarily intended for use as a de-esser, reducing unattractive high frequencies, with minimum coloration and loss of clarity.

Automatic time constants and optimisation techniques for the gain reduction minimises the number of controls. The advantage is not only simple operation but also increased performance for highly dynamic and inconsistent materials without the need for continuous readjustments.

With wide input range, up to +29dBu input and low noise, the MDS-2 can be used in many different applications.

The side chain can be switched to M-S, which can be used to “zoom” in on high frequencies in the centre of the stereo image. With this function switched in the threshold is 6dB lower for the centre image compared to extreme left and right.

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!