Gemini – Mastering M/S

Gemini is the first mid/side processor in 120V technology.
In mastering, M/S processing is often the best way to get targeted access to individual elements of a mix.

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M/S ?
The decomposition of the stereo signal in mid (voice, snare, bass …) and side (guitars, pads, cymbals …) allows their separate processing.
The center signal (Mid) is the sum of the left and right channel of the stereo signal (L+R), i.e. the “in phase” part of the stereo signal.
The side signal (Side) is the difference of the left and right channels of the stereo signal (L-R), i.e. the “out-of-phase” part of the stereo signal.
Gemini can also be used to enlarge or reduce the stereo image. An elliptical filter for shifting the low frequency component from the side to the mid is also on board.

The Mid
When the M/S button is activated, the input signal (L/R stereo) is split into a mid and side signals.
The exact center position can be adjusted with the Balance control and the exact level with the Trim control. Both functions are switchable to be in the signal path only when in use.
Exclusive monitoring of the center is possible when the solo function is activated. Processors can be inserted to process the mid signal and activated with the Insert button.

The Side
The side signal also has a solo function and a switchable insert for external processing. In addition, the elliptical filter can be used to shift the bass frequencies from the side to the mid.
This improves the punch and precision of low frequencies. The Stereo Width control changes the level of the side signal, with a level increase broadening the stereo image.
These two functions can also be switched on to be in the signal path only when used.

I/Os and Inserts
All inputs and outputs as well as sends and returns are balanced using Neutrik XLR connectors.
Processors can be connected to the inserts for external processing. Especially interesting is the integration of the Gemini into the Hermes Mastering Router.
In this way, processing chains can be created that combine classic L/R processing with M/S processing.

Gemini & Hermes
The M/S encoder and decoder stages of the Gemini can each be connected to an insert of the Hermes and freely positioned within the processing chain.
Processors that are in a chain between M/S encoder and decoder process the mid/side signal. These processors can also easily be mono devices.
In the example above, Insert Send A is routed to Gemini for M/S encoding. The mid/side sends of the Gemini go back to Return A of the Hermes.
Send B goes from Hermes back to the Gemini to be encoded back to L/R, which flows from the output of the Gemini back to Return B of Hermes.

Technical specifications


Analog inputs & output; XLR (balanced)
Maximum input & output gain: 32,5 dBu
Input impedance: 20 kΩ
Output impedance: 75 Ω
Common mode rejection: -79 dBu
Frequency range (-3 dB) 10 Hz – 150 kHz
Crosstalk (1 kHz) -108 dBu
THD + N (0 dBu, 1 kHz) -110 dBu
Noise (A-weighted), all stages active) -98,2 dBu
Dynamic range: 135 dB

Internal Linear Power Supply with Shielded Toroidal Transformer
Operating voltage for analog audio +/- 60 V
Operating voltage for relays and LEDs + 12 V

Mains Power Supply
Mains voltage (selectable, see fuse chamber) 230 V AC / 50; 115 V AC / 60 Hz
Fuse for 230 V: T 500 mA
Fuse for 115 V: T 1 A
Power consumption: max. 40 VA

Dimensions & Weight
W x H x D (width x height x depth) 482 x 44 x 300 mm / 19 x 1,73 x 11,8 inch
Unit weight: 5 kg / 11,02 lbs
Shipping weight (incl. packaging) 6.8 kg / 14,99 lbs