The Ensoniq KS-32 Weighted Action MIDI Studio represents a sophisticated synthesizer designed primarily for pianists and keyboard players who prioritize playing experience over programming complexity. Released in 1992, this instrument distinguished itself with a specially designed 76-note weighted keyboard featuring a flying-action weighted mechanism that simulates the physical movement of hammers inside an acoustic piano, providing the slight looseness characteristic of acoustic piano hammer actions.

The KS-32 functions as a comprehensive music production solution, combining a multi-timbral programmable digital synthesizer with onboard effects, a 16-track sequencer (including 8 "Song Tracks"), and MIDI master keyboard capabilities. Its sound architecture is built around 24 megabits (3 megabytes) of waveform ROM, with one full megabyte dedicated exclusively to 16-bit acoustic piano waveforms, reflecting its keyboard-player orientation.

The instrument's sound generation employs up to three voices per sound, with each voice created from three digital oscillators utilizing 168 samples of acoustic and synthetic sounds (waves), plus Ensoniq's proprietary Transwaves technology. The synthesis engine delivers 32 dynamically assigned voices with programmable voice priority. Polyphony varies depending on voice usage—sounds using three voices provide 10-note polyphony before voice stealing occurs. The system features programmable voice delay up to 250 milliseconds and supports modulatable start points with forward-backward playback modes on most samples, with both pitched and fixed frequency playback possible for all waves.

Sound quality is exceptional across the board, with particularly impressive piano presets ranging from the gloomy, sonorous Dark Grand to the punchy Rock Grand and contemporary House 90's Keys. The electric pianos include convincing Rhodes-style replicas, while the harpsichords achieve remarkable realism. Beyond keyboard sounds, the KS-32 excels with guitars, bass, brass, strings, choral sounds, and notably impressive analogue synth emulations. The onboard library includes 180 preset sounds (80 in RAM, 100 in ROM including 20 dedicated drum and percussion sets), expandable via ROM and RAM cards providing 160 additional sounds per card. With full compatibility with the SQ series sound library (over 1,000 sounds available), the system can access up to 340 sounds simultaneously with expansion cards.

The effects section utilizes a custom VLSI 24-bit digital signal processor (ESP chip) with 48-bit accumulation, the same technology found in Ensoniq's renowned DP/4 multi-effects unit, delivering professional-quality processing. Available effects include reverb, chorus, flanging, distortion, phase shifter, rotary speaker, and various effect combinations. The system features three stereo buses allowing for dry, individual, or grouped effects processing. All effects are fully programmable with extensive parameter control and dynamic performance control capability, with complete effect setups saved with each sound. Real-time control over effect parameters is possible via 16 selectable modulation sources including velocity, aftertouch, modulation wheel, pitch, and external MIDI control.

The KS-32's keyboard spans 76 keys (E to G) with programmable velocity and channel pressure sensitivity that transmits via MIDI. It offers 14 velocity response levels and multiple pressure settings, plus channel aftertouch (pressure), pitch and modulation wheels, and 16 programmable keyboard zones for complex splits and layers. A programmable dual footswitch input provides control over sustain, sequencer start/stop, and other assignable functions, while a mod/volume pedal input offers additional real-time expression control. Performance presets organize up to 16 sounds (not just eight) in groups, storing them in 100 memory locations for instant recall. These presets can include layers, upper/lower splits, and modified parameters such as volume, pan, timbre, key zone, transpose, release time, channel/poly-key pressure reception on/off, MIDI channel, MIDI status, program change, and sustain pedal on/off. A "Make Default Preset" command creates automatic preset templates with local/MIDI and upper/lower key split status instantly defined.

The integrated sequencer provides 16 polyphonic tracks (including 8 "Song Tracks"), each with separate sound, volume, and MIDI channel/status incorporating all Performance Preset parameters. Real-time recording offers three modes (Replace, Add, Looped) plus step entry recording. Comprehensive editing facilities include tap tempo, automated punch/edit points remembered for each sequence, step editing for correcting individual notes, post-quantization up to 1/64th-note triplets (auto-correct), bar and beat editing, clock and key range editing, transposition, time-shifting, append, extract, change length, track merge, and filter/scale controllers. All editing can be auditioned before saving changes, and the system includes auto-locate controls and adjustable click track. The sequencer stores up to 70 sequences in a 70 Sequence/30 Song structure, with 8,500 notes capacity standard (expandable to 58,000 notes with the optional SQX-70 memory expansion kit). Clock resolution operates at 96 PPQ (pulses per quarter note). These sequences can be organized into 30 songs, each with 99 steps and 99 repetitions per step, with independent track muting and transposition saved as song data.

Songs extend beyond simple sequence chains with the Song format providing up to 99 steps with up to 99 repetitions for each step. Each sequence track in a step can be individually transposed and/or muted for memory-efficient use. The system offers eight additional song-length tracks independent of individual sequences, each with assignable sounds and track parameters. A MIDI Auto Mix (automated mixdown) feature records all volume and panning changes for each track across the entire song length.

As a MIDI controller, the KS-32 supports Omni, Poly, Multi, Mono A, and Mono B modes. It operates as a multi-timbral instrument accommodating up to 8 simultaneous polyphonic MIDI channels with separate sounds and performance parameters. The system responds to global controllers in Mono modes for use with alternate controllers (MIDI guitars, wind controllers, etc.) and responds to poly-key pressure via MIDI. It transmits and responds to MIDI Song Position Pointer messages, with each sequence and song location recognized (00-99). The eight tracks can send MIDI information independently and polyphonically across eight different MIDI channels. Additional MIDI features include response to real-time and song position pointers.

The synthesis architecture features sophisticated programming capabilities that belie the instrument's user-friendly exterior. Standard sounds comprise up to three voices (waves per key simultaneously) plus effects, while drum sounds utilize up to 17 drum waves plus effects. Each voice begins with wave selection from 168 options capable of over 1,250 variations, modified by two independent multi-mode dynamic digital filters (low pass, high pass, variable bandwidth band pass) and an LFO. Three five-stage envelopes per voice control pitch, filter cutoff frequency, and amplitude, offering four time segments and four levels with 13 parameters per envelope (compared to traditional ADSR's three time segments and one level). Seventeen preset envelope templates covering common instrument types streamline programming.

The modulation matrix provides 16 sources routable to pitch, LFO depth, filters (1 & 2), volume, wave start index, and most effects parameters. Sources include LFO, multiple envelopes, noise generators, velocity, keyboard tracking, timbre, VCA footpedal, pitch bend, mod wheel, pressure, and external MIDI controllers.

Wave types divide into sampled acoustic instruments and synthetic/algorithmic sounds. The 168 wave selections include multi-sampled piano, strings, brass, and bass waves with timbre-shifted versions, sustained synthesizer waveforms with harmonic and inharmonic structures, TransWave spectral interpolation waves with real-time modulation capability, and acoustic and electronic drums (kicks, snares, tom-toms, hi-hats, cymbals). Percussion waves encompass Latin percussion, world music percussion, orchestra blasts, finger snaps, tambourine, and others. Most samples feature modulatable start points and forward-backward playback modes, with both pitched and fixed frequency playback possible for all waves.

The drum and percussion arsenal covers rock, pop, dance, Latin, and electro styles across 20 different drum and percussion sets mapped across the keyboard, with two kits following General MIDI specifications. Notable sounds include Steam Drum, Synth Kiss, and Slinky Pop, plus comprehensive acoustic and electronic drums (kicks, snares, tom-toms, hi-hats, cymbals) and diverse percussion including Latin percussion, world music percussion, orchestra blasts, finger snaps, and tambourine.

The KS-32 emerged as an evolutionary rather than revolutionary product, distinguished by its thoughtful integration of professional features in a user-friendly package. It serves equally well as a standalone music workstation or as the central instrument in a MIDI-based setup, making it particularly suitable for working musicians performing across multiple contexts—from band work to restaurant gigs to home studio production. The instrument's defining characteristic remains its weighted keyboard action, which delivers authentic piano feel while maintaining the versatility expected of a modern digital workstation.

Technical Specifications

General

• Type: Synthesizer/Workstation
• Year Released: 1992
• Original Price: approx USD 3200

Synthesis

• Engine Type: Digital
• Sound Generation: PCM (Pulse Code Modulation) + Wavetable (WT)
• Polyphony: 32 dynamically assigned voices with programmable voice priority
  • 32-note polyphony for single-voice sounds
  • 10-note polyphony for three-voice sounds (before voice stealing)
• Multitimbral: 16-part
• Oscillators per Voice: 3 digital oscillators
• Wave Memory: 24 Megabits (3 Megabytes) total waveform ROM
  • 1 Megabyte dedicated to 16-bit acoustic piano waveforms
  • 168 wave selections
  • Over 1,250 variations possible from wave selections
• Wave Types:
  • Multi-sampled piano, strings, brass, and bass waves with timbre-shifted versions
  • Sustained synthesizer waveforms with harmonic and inharmonic structures
  • TransWave spectral interpolation waves with real-time modulation
  • Acoustic and electronic drums (kicks, snares, tom-toms, hi-hats, cymbals)
  • Percussion waves (Latin percussion, world music percussion, orchestra blasts, finger snaps, tambourine, others)
• Wave Features:
  • Modulatable start point on most samples
  • Forward-backward playback mode on most samples
  • Pitched or fixed frequency playback of all waves possible
• Voice Delay: Programmable up to 250 milliseconds

LFO

• LFO per Voice: 1
• Waveforms: 4 types including Noise, Sample & Hold, Saw Up, Saw Down, Sine, Square, Triangle
• Modes: Clocked, Delay, Freerun, Key Sync

Noise Generator

• Types: Pink Noise, White Noise, Pulse, Pulse Variable

Filter

• Filters per Voice: 2 independent multi-mode dynamic digital filters
• Filter Types: Low Pass, High Pass, Variable Bandwidth Band Pass
• Slope: 24dB (4-pole)
• Features: Resonance

Envelopes

• Envelopes per Voice: 3 five-stage envelopes
• Functions: Pitch, Filter Cutoff Frequency, Amplitude
• Stages: 4 time segments, 4 levels (5 stages total)
• Parameters: 13 parameters per envelope
  • Delay, Attack, Decay, Decay 2, Sustain, Sustain Level, Release, Release 2
  • Rate 1-4, Level 1-4
• Features: Bi-Polar, Freerun, Looping, Monophonic, Offset, Polyphonic, Slope, Time
• Templates: 17 preset envelope templates for common instrument types (ease of programming)

Modulation

• Modulation Sources: 16 total
  • LFO, Env 1, Env 2, Amp, Noise 1, Noise 2
  • Velocity, Keyboard Tracking, Timbre
  • VCA footpedal, Pitch Bend, Mod Wheel
  • Mod Wheel plus Pressure, Pressure
  • External MIDI controllers
• Modulation Destinations: Pitch, LFO Depth, Filter 1 & 2, Volume, Wave Start Index, Most Effects Parameters

Effects

• Effects Processor: Custom VLSI 24-bit digital signal processor (ESP chip) with 48-bit accumulation
• Effect Types:
  • Reverb (Hall, Room, Warm Chamber)
  • Chorus (including 8-voice Chorus)
  • Flanging
  • Distortion
  • Phase Shifter
  • Rotary Speaker
  • Multiple effect combinations (Chorus/Reverb, Flanger/Reverb, Phaser/Reverb, Rotary Speaker/Reverb, Distortion/Chorus/Reverb, Compression/Distortion/Reverb)
• Programmability: Fully programmable stereo effects processing
• Performance Control: Dynamic performance control capability
• Real-time Control: 16 selectable modulation sources (including 6 ramps, velocity, aftertouch, mod wheel, pitch, external MIDI)
• Audio Routing: Three stereo buses allowing for dry, individual, or grouped effects processing
• Storage: Complete FX setup saved per sound

Memory & Sounds

• Preset Sounds: 180 total (without memory card)
  • 80 internal RAM sounds
  • 100 ROM sounds (including 20 dedicated drum and percussion sets)
• Card Expansion: 160 additional sounds available on each ROM/RAM card
• Performance Presets: 100 memory locations
  • Up to 16 sounds per preset (not 8)
  • "Make Default Preset" command for automatic preset template creation
• Sound Structure:
  • Standard sounds: Up to 3 waves per key simultaneously + effect
  • Drum sounds: Up to 17 drum waves + effect
• Drum Kits: 20 dedicated drum and percussion sets
• General MIDI: 2 kits mapped to GM specification
• Expansion Compatibility:
  • ROM and RAM card compatible
  • Full compatibility with SQ series sounds (over 1,000 sounds available)
  • Up to 340 sounds accessible simultaneously with expansion cards

Keyboard

• Keys: 76 notes (E to G range)
• Action: Weighted keyboard with flying-action weighted mechanism
• Velocity Sensitive: Yes (14 velocity response levels)
  • Programmable velocity sensitivity
  • MIDI transmission of velocity data
• Aftertouch: Yes (Channel Pressure/Channel Aftertouch)
  • Programmable channel pressure sensitivity
  • MIDI transmission of pressure data
• Pressure Settings: Multiple pressure settings available
• Keyboard Zones: 16 programmable zones for splits and layers

Controllers

• Pitch Bend Wheel: Yes
• Modulation Wheel: Yes
• Footswitch Input: Programmable dual footswitch
  • Sustain
  • Sequencer start/stop
  • Other assignable functions
• Pedal Inputs:
  • VCA Footpedal (supported)
  • Mod/Volume Pedal input

Sequencer

• Tracks: 16 polyphonic tracks total (including 8 "Song Tracks")
  • Each track with separate sound, volume, and MIDI channel/status
  • All Performance Preset parameters included per track
• Track Assignment: Internal sounds and/or external MIDI instruments
• Recording Modes: 3 real-time modes (Replace, Add, Looped) and Step Entry recording
• Sequence Structure: 70 Sequence/30 Song structure
• Sequence Memory: 8,500 notes capacity standard
  • Optional SQX-70 expansion: 58,000 total notes (49,500 additional)
• Clock Resolution: 96 PPQ (Pulses Per Quarter note)
• Songs: Up to 30 songs
  • Song format provides up to 99 steps per song
  • Up to 99 repetitions per step
  • Each sequence track in a step can be individually transposed and/or muted for memory-efficient use
• MIDI Auto Mix: Automated mixdown feature records all volume/panning changes for each track
• Editing Features:
  • Tap Tempo control
  • Automated punch/edit points remembered for each sequence
  • Step editing (individual note correction)
  • Post-quantization (auto-correct up to 1/64th-note triplets)
  • Bar/beat and clock editing
  • Key range editing
  • Transpose, time-shift
  • Append, extract, change length
  • Track merge
  • Filter/scale controllers
  • All editing can be auditioned before saving changes
• Transport Controls:
  • Auto-locate controls
  • Adjustable click track
• Track Control:
  • Track mute/solo
  • Volume, balance, and routing control
  • Individual track transposition and muting saved as song data

MIDI

• MIDI Modes: Omni, Poly, Multi, Mono A, Mono B
• MIDI Channels: 16 total
• Multi-timbral Capacity: Accommodates up to 8 simultaneous polyphonic MIDI channels with separate sounds and performance parameters
• MIDI Tracks: 8 tracks with independent polyphonic transmission
• Connectivity: MIDI In, MIDI Out/Thru
• Features:
  • Responds to global controllers in Mono modes for alternate controllers (MIDI guitars, wind controllers, etc.)
  • Responds to Poly-Key Pressure via MIDI
  • Transmits and responds to MIDI Song Position Pointer messages
  • Each sequence and song location recognized (00-99)
  • Master keyboard capabilities
  • Multitimbral sound module operation
  • Per-track MIDI parameter assignment
  • Program Change support
  • External MIDI control routing

Audio

• D/A Conversion: 16-bit with 96dB dynamic range
• Interpolation: First-order linear interpolation for wide transposition range
• Output Filters: Linear phase output filters
• Voice Panning: Stereo panning per voice
• Outputs:
  • Left and Right audio outputs (1/4" phone jack connectors)
  • Connecting either singly provides mono output
  • Separate front panel stereo headphone output
• Routing: Configurable per track to stereo outs via or bypassing effects

Performance Features

• Splits: Upper/lower keyboard splits
• Layers: Up to 8 sounds per performance preset
• Programmable Parameters per Preset:
  • Volume, Pan, Key Zone
  • Transpose, Release Time
  • MIDI Channel, Program Change
  • Global effect assignment
• Default Preset Configuration:
  • Tracks 1-4: Onboard local sounds
  • Tracks 5-8: MIDI control tracks
  • Tracks 3 & 7: Lower splits
  • Tracks 4 & 8: Upper splits

Physical

• Form Factor: Keyboard Synthesizer Workstation
• Dimensions: 49.5" (125.7 cm) wide x 4.5" (11.4 cm) high x 13.9" (35.3 cm) deep
• Weight: 49 pounds (22.2 kgs)

Compatibility

• Sound Library: Fully compatible with all SQ series sounds
• Expansion Cards: ROM and RAM cards supported