The Crumar Bit One, introduced in 1984, is a six-voice programmable touch-sensitive synthesizer that represents a compelling entry in the mid-1980s affordable polyphonic synthesizer market. As a hybrid digital/analog instrument, it combines digitally controlled oscillators with analog filtering to deliver a distinctive sonic character that balances the crispness of digital control with the warmth of analog signal processing.

Architecture and Sound Generation

At its heart, the Bit One employs twelve digitally controlled oscillators (DCOs) - two per voice - as its primary sound source. Each DCO offers three waveform options: triangle, sawtooth, and variable pulse width square wave. The oscillators feature a basic pitch range spanning four octaves (32', 16', 8', and 4' settings) and can be modulated by ADSR envelopes, LFOs, or the velocity-sensitive keyboard. The sound then passes through 24dB/octave low-pass resonant filters with full ADSR envelope control, cutoff and resonance parameters, keyboard tracking, polarity inversion, and envelope generator depth control.

The instrument's analog filter section provides the characteristic warmth expected from analog synthesis, while the digital control system ensures stable, accurate tuning and parameter recall. This hybrid approach produces sounds that are described as crisp, clean, and notably big and powerful, though perhaps not quite as immediately edgy as purely digital instruments of the era.

Modulation Capabilities

A standout feature of the Bit One is its dual LFO system, with two independent low-frequency oscillators per voice enabling complex modulation effects. Each LFO offers sine, square, and sawtooth waveforms and can be routed to DCO1, DCO2, the VCF, or the VCA. Users can control modulation depth, delay (allowing the modulation to fade in), and rate for each LFO independently.

The VCA (voltage-controlled amplifier) features standard ADSR envelope controls with values ranging from 0-63, providing precise control over amplitude shaping. All envelope and amplifier parameters work in concert with the instrument's extensive velocity sensitivity features.

Touch Sensitivity and Dynamic Control

One of the Bit One's most impressive features for its price point is its comprehensive velocity sensitivity implementation. Multiple parameters respond to playing dynamics, indicated by double-lined boxes on the front panel's block diagram. Velocity-controlled parameters include filter attack time, filter envelope depth, DCO pulse width, VCA attack time, and LFO rate. This allows players to achieve significant expressive control, with harder key strikes producing faster modulation, quicker attacks, and more pronounced filter effects. The basic level of touch sensitivity can be adjusted via a control on the rear panel, though this setting applies globally rather than per-patch.

Programming and User Interface

The Bit One utilizes digital access control for parameter programming - a cost-effective and accurate method that was becoming standard in mid-1980s synthesizers. Programming is accomplished through a ten-digit keypad system where users press an 'address' button, enter the parameter number via the keypad, and adjust values using 'on' (plus) and 'off' (minus) keys. Display screens show the current parameter and its value. Many parameters are binary (on/off) such as waveform selection and basic pitch, while others like envelope settings offer a range of 0-63 values.

The front panel features a helpful block diagram flow chart that visually explains the routing of parameter banks, making it easy to understand the signal path at a glance. While this programming method requires referring to the front panel map during editing, it provides a logical and organized approach to sound design.

The instrument includes several thoughtful programming features that enhance workflow. A 'park' feature allows users to hold a sound temporarily while searching for an appropriate memory location - particularly useful for day-to-day programming sessions. An edit/compare function enables quick A/B comparison between an original patch and edited versions, facilitating efficient sound refinement.

Performance Modes and Keyboard Functionality

The Bit One offers four distinct performance modes. In standard six-voice polyphonic mode, the instrument provides full polyphony across its 61-key velocity-sensitive keyboard. Split mode allows two different sounds to be assigned to user-defined upper and lower keyboard sections, though this reduces polyphony to three voices per section. Double mode combines two sounds simultaneously with independent volume controls for each, again limiting total polyphony to three notes. Finally, Unison mode combines all available oscillators for thick, monophonic lead sounds.

The split point is infinitely adjustable, providing flexibility in performance setup, though split and double configurations cannot be stored in the instrument's memory - a notable limitation. All 64 patches can be assigned to upper or lower sections of the keyboard for quick access in split mode.

A dedicated unison switch activates monophonic mode regardless of whether the keyboard is in whole, double, or split configuration, making it ideal for creating powerful lead and bass lines with all oscillators working together.

Additional Controls and Features

Above the unison button sit two important but non-programmable controls: noise level and detune. The noise generator is a mixed blessing - while it can be processed by the VCF and VCA, creating pure noise effects requires programming a patch with both oscillators turned off. The detune control lowers DCO2's pitch by up to a semitone relative to DCO1, allowing for chorus-like thickness and detuned textures, though its non-programmable nature means settings cannot be stored per-patch.

Standard performance controls include modulation and pitch wheels, positioned relatively high on the control panel. A release footswitch can be connected via the rear panel for additional performance control.

Audio Outputs and Stereo Imaging

The Bit One features stereo outputs with an unusual voice allocation system. In normal playing modes, individual notes are distributed seemingly randomly between hard left and hard right positions, creating an interesting stereo field. When operating in split mode, the stereo outputs logically become dedicated upper and lower voice outputs, allowing each keyboard section to be independently EQ'd or processed. For situations where this stereo behavior isn't practical (such as live performances), the instrument functions perfectly well in mono by using only the upper output.

MIDI Implementation

The instrument includes MIDI In, Out, and Thru connections, though the initial MIDI implementation was limited, operating only on MIDI Channel 1 and primarily functioning in receive mode rather than transmitting information. However, the manufacturers promised free software updates to expand MIDI functionality, including assignable channel selection across all 16 MIDI channels. This update was planned to coincide with the release of companion products including an expander module, drum machine, and sequencer.

Memory and Sound Storage

The Bit One provides 64 programmable memory locations for storing user-created patches. The memory system is straightforward and reliable, utilizing the digital control system for accurate recall. Each stored patch contains all oscillator, filter, amplifier, LFO, and envelope settings. However, keyboard split and double mode configurations cannot be stored, requiring manual setup for each performance session.

Build Quality and Physical Design

The ten-digit keypad buttons were noted to be somewhat wobbly in feel, and the positioning of the modulation and pitchbend wheels vertically on the front panel (one above the other) rather than beside the keyboard was considered potentially awkward for certain playing techniques, particularly when attempting to play bass parts with one hand while reaching over to access the wheels.

Factory Sounds and Sonic Character

Reviews noted that while the instrument was capable of producing high-quality sounds with some programming effort, the factory presets were considered rather average and uninspiring, apparently created quickly rather than showcasing the instrument's full potential. The overall tonal character was described as somewhat nasal - a common characteristic of DCO-based synthesizers compared to VCO-based instruments. The instrument excelled at crisp, clean sounds with generous oscillator presence, creating big and powerful tones particularly suited to the mid-1980s aesthetic.

Design Philosophy

The Bit One was clearly designed as a player's instrument - straightforward, down-to-earth, and capable of delivering high-class sounds quickly without requiring extensive programming knowledge. The inclusion of comprehensive velocity sensitivity, dual LFOs per voice, split and double modes, and thoughtful workflow features like the park and edit/compare functions demonstrated a focus on practical musicianship. However, certain design decisions raised questions, particularly the choice to make critical parameters like detune and noise level non-programmable, and the inability to store split and double mode configurations.

Market Position

The Bit One occupied an interesting position in the mid-1980s synthesizer market, offering features typically associated with more expensive instruments at an accessible price point. Six-voice polyphony, dual oscillators per voice, touch sensitivity, 64 program memories, and multiple performance modes represented significant value. While it didn't break new technical ground, it packaged existing technologies in a thoughtful, musically useful way that prioritized playability and immediate results over complex programming or exotic features.

Technical Specifications

Production Years: 1984-1986

Architecture:

• Hybrid Digital/Analog design
• Digital control system
• Analog filters and signal path

Polyphony: 6 voices

Oscillators:

• 2 DCOs (Digitally Controlled Oscillators) per voice
• Total of 12 DCOs
• Waveforms: Triangle, Sawtooth, Variable Pulse Width Square
• Pitch Range: 32', 16', 8', 4'
• Modulation Sources: ADSR, LFO, Velocity

Low-Frequency Oscillators:

• 2 LFOs per voice
• Waveforms: Triangle (Sine), Ramp (Sawtooth), Square
• Modulation Destinations: DCO1, DCO2, VCF, VCA
• Controls: Depth, Rate, Delay
• LFO Rate: Velocity-controllable

Filter:

• Type: Resonant low-pass filter
• Slope: 24dB/octave
• 1 VCF per voice
• Envelope: ADSR (Attack, Decay, Sustain, Release)
• Controls: Cutoff, Resonance, Envelope Depth, Keyboard Tracking, Polarity Inverter
• Velocity-Sensitive Parameters: Attack Time, Envelope Depth

Amplifier:

• 1 VCA (Voltage-Controlled Amplifier) per voice
• Envelope: ADSR
• Parameter Range: 0-63 for all envelope values
• Velocity-Sensitive Parameters: Attack Time, Amount

Noise Generator:

• White noise source
• Non-programmable level control
• Routable through VCF and VCA

Keyboard:

• 61 keys
• Velocity-sensitive (touch-sensitive)
• Adjustable sensitivity (rear panel control)

Performance Modes:

• Polyphonic: 6-voice polyphony
• Split: Dual sounds with user-defined split point (3 voices per section)
• Double: Two sounds layered (3-note polyphony)
• Unison: All oscillators combined (monophonic)

Velocity-Sensitive Parameters:

• Filter Attack Time
• Filter Envelope Depth
• DCO Pulse Width
• VCA Attack Time
• LFO Rate

Memory:

• 64 programmable memory locations
• Park feature for temporary sound storage
• Edit/Compare function
• Split and Double modes not storable

Controls:

• Programming: 10-digit keypad with Address button
• Parameter adjustment: On/Off (Plus/Minus) buttons
• LED display screens
• Modulation wheel (front panel, vertical arrangement)
• Pitch bend wheel (front panel, vertical arrangement)
• Detune slider (non-programmable)
• Noise level slider (non-programmable)
• Volume controls for Upper/Lower in Split/Double modes
• Unison switch

Audio Outputs:

• Stereo outputs (Left/Right)
• Mono operation (Upper output only)
• Random voice distribution in normal mode
• Upper/Lower distribution in Split mode
• Headphone output (rear panel)

MIDI:

• MIDI In
• MIDI Out
• MIDI Thru
• Initial implementation: Channel 1 only, receive mode
• Planned update: Full 16-channel assignability and transmit capability

Additional Connections:

• Tape In/Out (cassette program dump)
• Trigger Output
• Release Pedal input

Rear Panel Controls:

• Master Pitch control
• Dynamic Sensitivity adjustment