The Moog Subsequent 25 is a premium two-octave analog monosynth that distills the essence of Moog's acclaimed Subsequent 37 into a more compact, focused instrument. This synthesizer represents a carefully engineered evolution in Moog's Sub series lineage, incorporating the sonic improvements of the Subsequent 37 while maintaining the accessible form factor reminiscent of the Sub Phatty.

Design & Build Quality The Subsequent 25 maintains Moog's signature premium construction with a steel chassis, elegant wooden end cheeks, and an aluminum curved back panel. The classic sloped design, which originated with the Moog Little Phatty, creates both an aesthetic statement and practical ergonomics. Every control feels substantial, with butter-smooth knobs that reflect the uncompromising build quality Moog is known for. Measuring 514 x 375 x 171mm, it's significantly more desk-friendly than its larger sibling while retaining the same premium feel.

Synthesis Architecture At its core, the Subsequent 25 is a two-note paraphonic analog monosynth featuring dual variable waveform oscillators, a classic Moog sub-oscillator, and the legendary Moog ladder filter. The synthesis engine is virtually identical to the Subsequent 37, ensuring the same sonic character and capabilities in a more streamlined package.

The dual oscillators offer comprehensive waveform control, sweeping from triangle through sawtooth, square, and pulse waves. Oscillator 2 features an additional ±7 semitone detune control and Hard Sync capability for more complex timbres. A unique "beat frequency" function provides linear constant detuning, creating consistent beating between oscillators regardless of the played note.

Classic Moog Filter & Processing The heart of the Subsequent 25's sound lies in its classic Moog ladder filter, which delivers the warm, musical resonance that has defined countless recordings. The filter features variable slope settings (6dB, 12dB, 18dB, or the classic 24dB per octave) accessible via hidden parameters. The Multidrive control adds everything from gentle tube-like warmth to aggressive clipping, while the mixer section provides pleasing overdrive characteristics when pushed past 12 o'clock.

Modulation & Envelopes The modulation section features a single LFO with five waveforms (triangle, square, sawtooth, inverse sawtooth, and sample & hold) plus a unique filter envelope setting. The LFO offers three selectable frequency ranges (0.01-10Hz, 0.1-100Hz, or 1-1000Hz) and can sync to MIDI clock with divisions from four whole notes to 1/64th notes.

Two comprehensive DAHDSR envelopes control the filter and amplifier, with attack, decay, sustain, and release controls on the front panel, while delay and hold parameters are accessible through the shift mode system.

Paraphonic Duo Mode The "Duo mode" allows the two oscillators to be played independently across the keyboard, with Oscillator 2 tracking either the highest or lowest note played. This paraphonic capability expands the instrument's versatility beyond traditional monophonic synthesis.

Hidden Parameters System A clever solution to the space constraints, Moog has implemented a comprehensive "hidden parameters" system that provides access to advanced functions through shift-mode combinations. This system preserves nearly all the functionality of the Subsequent 37 while maintaining a clean, uncluttered interface. A tear-out reference card helps navigate these functions, and the optional software editor provides complete visual access to all parameters.

Connectivity & Integration The side-mounted connection panel provides comprehensive I/O including MIDI in/out via both 5-pin DIN and USB, CV inputs for gate, pitch, volume, and filter, balanced audio in/out, and an internal power supply. The instrument can function as a MIDI interface and offers extensive MIDI implementation including control changes, NRPN assignments, and SysEx support.

Technical Specifications

Synthesis Engine

• Type: Two-note paraphonic analog monosynth
• Oscillators: 2 x variable waveform oscillators (triangle, sawtooth, square, pulse)
• Sub-oscillator: Fixed square wave, one octave below Oscillator 1
• Hard Sync: Oscillator 2 to Oscillator 1 phase lock
• Beat Frequency: ±3.5Hz linear constant detuning
• Octave Transpose: 4 octave range per oscillator
• Detune: ±7 semitones on Oscillator 2

Filter

• Type: Classic Moog ladder filter
• Slopes: 6dB, 12dB, 18dB, or 24dB per octave (selectable)
• Controls: Cutoff, Resonance, Envelope Amount, Keyboard Tracking
• Multidrive: Variable saturation from tube warmth to aggressive clipping

Envelopes

• Type: 2 x DAHDSR (Delay, Attack, Hold, Decay, Sustain, Release)
• Assignment: Filter and Amplifier
• Front Panel Controls: Attack, Decay, Sustain, Release
• Hidden Parameters: Delay, Hold, Velocity sensitivity

Modulation

• LFO: Single LFO with 5 waveforms
• Waveforms: Triangle, Square, Sawtooth, Inverse Sawtooth, Sample & Hold, Filter Envelope
• Frequency Ranges: 0.01-10Hz, 0.1-100Hz, 1-1000Hz (selectable)
• MIDI Sync: Yes, with clock divisions from 4 whole notes to 1/64th
• Destinations: Pitch (both/individual oscillators), Filter Frequency, Oscillator Waveform

Keyboard & Controls

• Keys: 25-key (2 octave), velocity sensitive
• Aftertouch: Not available on keyboard (MIDI aftertouch reception supported)
• Wheels: Modulation and Pitch Bend
• Octave Buttons: ±2 octave transpose
• Front Panel: 31 knobs, 13 buttons

Memory & Presets

• Presets: 16 total (4 banks of 4)
• Preset Access: Direct button access via 4x4 grid
• Modulation Wheel: Position saveable per patch

Audio Specifications

• Inputs: External audio input, CV inputs (Gate, Pitch, Volume, Filter)
• Outputs: Balanced audio output, headphone output (front panel)
• Feedback: Internal feedback routing available
• Mixer: 4-channel (Osc 1, Osc 2, Sub-osc, Noise) with overdrive characteristics

MIDI Implementation

• Ports: 5-pin DIN and USB (simultaneous operation)
• Channels: Selectable input/output channels
• Messages: Control Changes, NRPN, SysEx, Program Changes
• Functions: MIDI merge, Thru routing, message filtering
• Aftertouch: Reception only (filter cutoff destination)

Physical Specifications

• Dimensions: 20.25” x 14.75” x 6.75”/ 514 x 375 x 171mm (W x D x H)
• Weight: 16.5 lbs/ 7.48kg
• Construction: Steel chassis, wooden end cheeks, aluminum back panel

Power

• Internal 100-240V, 50/60Hz AC power supply (IEC connector)

Software Integration

• Editor: Free software editor (VST, AU, RTAS, AAX)
• Platforms: Mac and PC support
• Functions: Complete parameter access, preset management, DAW automation
• Connection: USB MIDI

Hidden Parameters (Partial List)

• Duo mode enable/disable
• Pitch bend ranges
• LFO re-triggering options
• Glide types (constant rate, constant time, exponential)
• Filter slope selection
• LFO frequency ranges
• Envelope looping
• MIDI channel settings
• Note priority settings
• Oscillator phase reset

Factory Included Accessories

• Manual with tear-out reference card for hidden parameters
• Free software editor (download after registration)
• Power cable

Comparison Notes

vs. Subsequent 37:

• Shorter keyboard (25 vs. 37 keys)
• Single LFO (vs. dual LFOs)
• No aftertouch on keyboard
• No sequencer or arpeggiator
• Fewer presets (16 vs. 256)
• No LCD display
• More compact form factor

Retained from Subsequent 37:

• Same synthesis engine and sonic character
• Duo (paraphonic) mode
• Enhanced mixer with double headroom
• Improved filter characteristics
• Premium build quality