GS Music Bree6 Keyboard Blue is a 6-voice analog polyphonic synthesizer from Argentine manufacturer GS Music — the company's first instrument with an integrated keyboard. The enclosure is all-metal with natural cedar wood side panels, hand-assembled in Argentina. The signal path is fully analog: one VCO plus a sub-oscillator per voice, a 4-pole ladder low-pass filter, and a VCA. Control voltages are digitally generated, providing tuning stability without compromising the analog character of the signal chain. Available in blue and black colorways at $1,699 USD.
Analog signal path and ladder filter with key tracking and self-oscillation
The VCO per voice runs simultaneous sawtooth and pulse waves with adjustable pulse width modulation. A sub-oscillator one octave below fills the low end without consuming an additional oscillator slot per voice. The 4-pole 24 dB/oct ladder filter with resonance tracks the keyboard at 1V/oct — at high resonance and full keyboard tracking, it enters self-oscillation, producing a clipped sine-like tone that blends into the oscillator mix. Filter modulation is handled by EG1 with velocity-sensitive modulation depth, the mod wheel, aftertouch, and the LFO simultaneously. EG2 controls the VCA. The LFO spans 0.1 to 100 Hz with five waveforms — triangle, ramp up, ramp down, square, and sample and hold — routable to VCO pitch, PWM, filter cutoff, and VCA level at the same time. The onboard stereo DSP effects processor (32-bit, 48 kHz, 24-bit converters) delivers an ensemble-type chorus and a stereo delay up to 1 second, with the dry analog signal remaining available at any mix ratio.
Semi-weighted keybed with aftertouch, sequencer, arpeggiator and MPE
The 3-octave semi-weighted keybed is velocity and aftertouch sensitive. Pitch bend and modulation wheels are designed and manufactured in-house by GS Music. Dedicated sustain and expression pedal inputs cover standard and configurable assignments with adjustable response range. The Keyboard version is the only Bree6 configuration that includes a built-in sequencer and an advanced multi-mode arpeggiator with double and triple operation modes, enabling complex rhythmic patterns without a computer. Full MPE (MIDI Polyphonic Expression) support allows per-note independent control of pitch, pressure, and timbre from a compatible MPE controller. 512 preset slots. Rear panel: power input, USB (data), 5-pin MIDI IN/OUT/THRU, balanced stereo L/R outputs with mono option, and headphone output. Designed and hand-assembled in Argentina by GS Music, founded in 2014 and responsible for the E7, the first fully analog polyphonic synthesizer designed and manufactured in Argentina.
KEY FEATURES
- 6-voice polyphony, fully analog signal path per voice
- VCO (sawtooth + pulse with PWM) + sub-oscillator per voice
- 4-pole ladder LP filter, 24 dB/oct, resonance with self-oscillation, 1V/oct key tracking
- 2 x ADSR (EG1: filter, EG2: VCA) with velocity-sensitive modulation depth
- LFO 0.1–100 Hz (triangle, ramp up, ramp down, square, S&H); routing to VCO/PWM/VCF/VCA
- Effects processor: ensemble chorus + stereo delay up to 1 s (32-bit DSP, 48 kHz, 24-bit converters)
- 3-octave semi-weighted keybed, velocity and aftertouch
- Pitch bend and mod wheels — in-house GS Music design
- Sustain and expression pedal inputs (configurable assignment)
- Sequencer and advanced arpeggiator (double/triple modes) — Keyboard version exclusive
- MPE (MIDI Polyphonic Expression): per-note pitch, pressure, timbre
- 512 presets
- All-metal enclosure with natural cedar wood sides, hand-assembled in Argentina
TECHNICAL SPECIFICATIONS
- Polyphony: 6 voices
- Oscillator: 1 x VCO + sub-oscillator per voice (sawtooth + pulse with PWM)
- Filter: 4-pole ladder LP, 24 dB/oct, resonance with self-oscillation, key tracking
- Envelopes: 2 x ADSR (EG1 → VCF, EG2 → VCA)
- LFO: 1 x (triangle/ramp up/ramp down/square/S&H), 0.1–100 Hz
- Effects: ensemble chorus + stereo delay (up to 1 s); 32-bit DSP, 48 kHz, 24-bit converters
- Keyboard: 3 octaves, semi-weighted, velocity, aftertouch
- Controllers: pitch bend + mod wheel (in-house design), octave ±
- Pedal inputs: sustain, expression (configurable)
- Sequencer + arpeggiator (double/triple modes) — Keyboard version only
- MPE: yes
- Presets: 512
- MIDI: 5-pin DIN IN/OUT/THRU
- USB: data port
- Audio out: balanced stereo L/R (with mono option), headphone out
- Enclosure: all-metal + natural cedar sides, hand-assembled
