SPL Gemini – M/S Mastering Processor (Red) SPL

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.

What Is 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 With 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.

The 120V technology
The 120V technology is our reference technology. The 120V technology is unique in the world. It operates at a DC voltage of 120 volts. This is four times that of IC-based semiconductor op-amps.

The highest possible audio quality requires the highest possible audio operating voltage. The 120V technology works with +/-60 V. To be able to handle such a high voltage, we have developed special proprietary operational amplifiers that can operate with a DC voltage of +/-60 V: the SPL 120V SUPRA operational amplifiers. This high voltage would destroy conventional components and operational amplifiers.

The 120V technology achieves exceptional technical specifications and sonic benefits. Technically, in terms of dynamic range, signal-to-noise ratio and headroom. Sonically, in terms of richness of detail and an absolutely relaxed listening experience.

By the way, the “120V” in the name of the technology has nothing to do with the local mains voltage from the mains power socket. This is about the operating voltage inside the device with which the audio signals are processed.

The mains voltage from the mains power socket is transformed to the required secondary voltage in the device’s internal linear power supply with toroidal transformer. Rectifiers convert this AC voltage into DC voltage required in the audio device.