MASTERING

Gemini

Mastering M/S Processor

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.

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 Gemini turns everything in mid/side. This is pretty crazy, because I can turn not just a single unit in mid/side, but an entire rack. This is a great unit.”

“The Gemini is the gear that reinvented all of my others gears. For me it would be hard to work without this equipment nowadays.”

“Definitely one of the tools I don’t want to miss on any project!”

“Before the Gemini, I used to use the SPL M/S Master. But again. The 120V DC audio rail rules 🙂 Gemini is the analog hardware which gives me the opportunity to shape the mid and side separately.”

“Gemini is a very clean M/S processor and I do use the elliptic filter a lot.”

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.

Hardware and M/S-Mastering: SPL Hermes + Gemini - Test/Review/Workshop/Tutorial (The Soundphile)

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.

For example, it is possible (see figure above) to place the M/S encoder at processing position 3, an equalizer at processing position 4 for separate processing of the mid and side signals, and then the M/S decoder stage of the Gemini at processing position 5 to generate an L/R stereo signal again.

If a compressor is now to be used as an additional device for M/S processing, it can simply be set to processing position 5 in the chain, and the M/S decoder stage would move to processing position 6 accordingly.

This video leads you step by step through Gemini.

This video introduces you to the entire mastering series.

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.

The idea for SPL 120V technology and the SUPRA operational amplifier based on this technology were developed in the 1990s by SPL founder and chief developer Wolfgang Neumann.

With the goal of building the best mastering console ever, this basic technological philosophy then took shape for the first time – thus the SPL MMC1 Mastering Console for Galaxy Studios saw the light of day in 2000.

The outstanding sonic and technical features quickly got around in the scene – so further orders were not long in coming.

Besides the MMC 1, another legendary product with 120V technology was created with the PQ, the “King of Parametric Equalizers”.

Since that time, 120V technology has been the foundation for all SPL premium products. Meanwhile, not only for mastering applications, but also for the, studio or hifi use.

What exactly is that?

And what does it do?

Good questions need good answers.

And that’s what the 120V technology video gives you.

Comparison

Most audio devices work with an internal operating voltage of +/-15 volts and can thus process a maximum input level of +21.5 dBu. If a DAC, for example, has an output level of +22 dBu at 0 dBFS, level peaks of the music material would already cause overloads in the input stage of the device.
All components in the audio device often operate at their limits. The result is an unsteady sound that causes stress and faster ear fatigue.

SPL devices with 120V technology can handle input levels of +32.5 dBu thanks to the higher internal operating voltage of +/- 60 volts – thus offering 12 dB more headroom. All components consequently operate continuously in the optimum operating range. The result is a very pleasant, natural and relaxed sound experience. So you can enjoy your music in every detail.

These diagrams clearly show the superiority of the 120V technology in comparison to other circuits with lower, common operating voltages.

Home is where the heart is

That’s why we manufacture all devices in our own production facility in Niederkrüchten on the Lower Rhine, Germany.

Videos

Hardware- und M/S-Mastering: SPL Hermes + Gemini - Test/Review/Workshop/Tutorial (The Soundphile)

This video leads you step by step through Gemini.

SPL Mastering Gear @ Studio DMI with Luca Pretolesi

SPL Meets Mastering Academy - Part 1 - Mastering

SPL Meets Mastering Academy - Part 2 - Q&A

SPL User Story: AUDIOMEISTEREI

Reviews

Studio Magazin

Gemini Blog Posts

Manuals

Replacing fuses and voltage selection

The replacement of fuses and the switching of mains voltages must only be performed by qualified technicians. Fuses must only be replaced with fuses of the same type and specifications.

Replacement of defective fuses for 115V

Replacement of defective fuses for 230V

Changing the mains voltage from 115V to 230V

Changing the mains voltage from 230V to 115V

Specifications

Print view

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

Reference: 0 dBu = 0,775V. All specifications are subject to change without notice.

Other Mastering Series Products

Mercury

Mastering D/A Converter

Hermes

Mastering Router

MC16

16-channel Monitor Controller

DMC

Mastering Console

IRON

Mastering Compressor

Mastering Equalizer

PASSEQ

Passive Mastering Equalizer

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MASTERING

Gemini

Mastering M/S Processor

M/S ?

The Mid

The Side

Hardware and M/S-Mastering: SPL Hermes + Gemini - Test/Review/Workshop/Tutorial (The Soundphile)

I/Os and Inserts

Gemini & Hermes

This video leads you step by step through Gemini.

This video introduces you to the entire mastering series.

The 120V technology

Comparison

Home is where the heart is

Videos

Hardware- und M/S-Mastering: SPL Hermes + Gemini - Test/Review/Workshop/Tutorial (The Soundphile)​

This video leads you step by step through Gemini.​

SPL Mastering Gear @ Studio DMI with Luca Pretolesi

SPL Meets Mastering Academy - Part 1 - Mastering

SPL Meets Mastering Academy - Part 2 - Q&A

SPL User Story: AUDIOMEISTEREI

Reviews

Studio Magazin

Gemini Blog Posts

Exploring the SPL Gemini – with Selam Katana

Mastering Cro – Duo Mastering Masterclass

Video – Justin Gray Music

Duo Mastering – Studiosofa Podcast

Audiosteps x SPL – Community Event & Mastering Workshop

Gemini @ Amazona

Manuals

Replacing fuses and voltage selection

Replacement of defective fuses for 115V

Replacement of defective fuses for 230V

Changing the mains voltage from 115V to 230V

Changing the mains voltage from 230V to 115V

Specifications

Analog inputs & output; XLR (balanced)

Internal Linear Power Supply with Shielded Toroidal Transformer

Mains Power Supply

Dimensions & Weight

Other Mastering Series Products

Series One

500er Serie

Classics

Optionen

Series One

500 Series

Classics

Options

Calculation of VAT (value added tax)

What does it actually mean …

Was bedeutet eigentlich …

Events

Events

Series One

500 Series

Classics

Options

Series One

500er Serie

Classics

Optionen

Anmelden

Hardware- und M/S-Mastering: SPL Hermes + Gemini - Test/Review/Workshop/Tutorial (The Soundphile)

This video leads you step by step through Gemini.