Product details

The SPL Audio Gemini is a professional analog mid/side mastering processor designed to provide precise control over stereo imaging and independent processing of the center and side components of a stereo mix. By encoding a left/right stereo signal into mid and side signals, it allows mastering engineers to target central elements such as vocals, kick drums, and bass separately from spatial elements such as guitars, reverbs, and cymbals. With dedicated balance and trim controls, adjustable stereo width, an elliptical filter, and external processing inserts, the Gemini offers a flexible solution for detailed stereo mastering. Its proprietary SPL 120V technology provides high headroom and a wide dynamic range for demanding professional audio applications.

Key Features

Mid/Side Encoding and Decoding: Converts a conventional left/right stereo signal into mid and side components for independent processing before reconstructing the stereo output.
Mid Signal Control: Dedicated Balance and Trim controls adjust the center signal’s stereo position and level relative to the side signal.
Mid Solo Monitoring: Isolates the mid component for focused evaluation of centered elements, including vocals and bass.
Side Solo Monitoring: Allows engineers to audition the side component independently when assessing stereo ambience and width.
External Processing Inserts: Separate inserts for mid and side signals enable integration of external equalizers, compressors, and other mastering processors.
Stereo Width Control: Adjusts the side-signal level to increase or reduce the perceived width of the stereo image.
Elliptical Filter: Reduces low-frequency content in the side signal, helping concentrate bass energy toward the center for improved mono compatibility and low-frequency focus.
Switchable Processing Stages: Balance, Trim, Stereo Width, and elliptical filtering can be switched into the signal path when required.
SPL 120V Technology: Operates the analog audio circuitry at ±60 V, providing high headroom and supporting clean signal handling at professional mastering levels.
Balanced XLR Connectivity: Neutrik XLR connectors provide balanced analog input, output, and send/return connections.
Mastering Router Integration: Works with the SPL Hermes Mastering Router to position M/S encoding and decoding at different points in a mastering chain.
Rackmount Design: Professional 19-inch, 1U construction for integration into mastering and high-end studio racks.

Technical Specifications

Product Type: Analog M/S mastering processor
Processing: Stereo M/S encoder and decoder
Analog Inputs: Balanced XLR
Analog Outputs: Balanced XLR
External Inserts: Balanced XLR send and return connections for mid and side processing
Maximum Input Level: +32.5 dBu
Maximum Output Level: +32.5 dBu
Input Impedance: 20 kΩ
Output Impedance: 75 Ω
Frequency Response (-3 dB): 10 Hz–150 kHz
Crosstalk (1 kHz): -108 dBu
THD + N (0 dBu, 1 kHz): -110 dBu
Common-Mode Rejection: -79 dBu
Dynamic Range: 135 dB
Noise (A-weighted, all stages active): -98.2 dBu
Analog Operating Voltage: ±60 V
Relay and LED Operating Voltage: +12 V
Power Supply: Internal linear power supply with shielded toroidal transformer
Mains Voltage: Selectable 230 V AC / 50 Hz or 115 V AC / 60 Hz
Maximum Power Consumption: 40 VA
Dimensions (W × H × D): 482 × 44 × 300 mm
Rack Format: 19-inch, 1U
Unit Weight: 5 kg