The Yamaha SY77 Music Synthesiser represented a significant evolution in digital synthesis technology, designed to bridge the gap between the raw musical power of Frequency Modulation and the realistic reproduction capabilities of digital sampling. By incorporating two distinct tone generation systems, Advanced Frequency Modulation (AFM) and second-generation Advanced Wave Memory (AWM2), the instrument offered unprecedented versatility.
The true innovation, however, lay in the interaction between these systems through Realtime Convolution and Modulation (RCM). This technology allowed AWM2 samples to modulate AFM operators, creating a fusion of sample realism and FM expressiveness that expanded the sonic palette far beyond the capabilities of either system in isolation. The Yamaha SY77 was positioned as a complete production workstation, combining sophisticated sound design with a full-featured 16-track sequencer and multi-timbre capabilities.
The AWM2 system utilised 16-bit linear waveform data sampled at 32 or 48 kilohertz, with 24-bit internal signal processing and high-resolution 22-bit digital-to-analogue converters. This configuration provided clarity and realism that rivaled compact disc players, particularly for acoustic instruments and natural timbres. The instrument included 4 megabytes of sampled waveform ROM, offering 112 individual built-in waveforms. External wave cards allowed for further expansion of this library. Unlike static sampled instruments, the AWM2 waveforms could be shaped in real time using a versatile digital filter system, and they could be layered or blended with AFM output in various configurations.
The AFM system represented a substantial refinement of the original DX7 technology. While retaining the basic principles of FM synthesis, the Yamaha SY77 expanded the algorithmic structure to 45 different algorithms, each capable of supporting up to three independent feedback loops. The operators were no longer restricted to simple sine waves; instead, any of 16 different preset waveforms could be assigned to each operator. This system included enhanced FM parameters, six-segment envelope generators for each operator with adjustable delays and segment looping, and four-breakpoint rate scaling. The integration of RCM synthesis meant that complex AWM2 waveforms could modulate any of the operators, resulting in a spectral output that was virtually unlimited.
RCM synthesis functioned by allowing AWM2 samples to be used as part of an AFM algorithm, adding harmonic content to the already complex waveform. The AWM2 sample could be filtered and enveloped prior to modulation, and the raw AFM output could be further filtered before panning, effect processing, and final output. This process was fully controllable, allowing for the creation of waveforms of unequalled complexity. The “straight” AWM2 output could also be mixed with the AWM2-modulated AFM output, providing a wide range of sonic possibilities that combined the realism of sampling with the dynamic expressiveness of FM.
The voice architecture of the Yamaha SY77 was built around a concept of “elements,” where each voice could be composed of one, two, or four elements. Each element could be assigned either an AWM2 or AFM waveform, resulting in 11 distinct voice modes. These modes ranged from pure AFM mono and poly configurations to pure AWM2 poly configurations, and mixed modes that enabled RCM synthesis. A special drum voice mode allowed for the assignment of 61 AWM samples to a single voice, utilising the instrument’s multi-timbre capabilities. AWM2 elements featured a 5-segment amplitude envelope generator, allowing for the patching of specific attack characteristics to different sustain types, such as combining a piano attack with a synth-brass sustain.
Each voice element was equipped with two advanced digital convolution filters, resulting in a maximum of eight filters operating simultaneously in a four-element voice. One filter was a low-pass type, while the other was switchable for either low-pass or high-pass response. Each filter had its own 6-segment envelope generator, enabling a wide range of dynamic filtering patterns. The filters could be combined to create bandpass responses or dual low-pass configurations with a 24-dB/octave rolloff slope. A resonance parameter allowed the cutoff-frequency peak to be boosted into oscillation, mimicking the character of analogue synthesiser filters.
Dynamic panning was implemented through individual pan envelope generators for each element, allowing the output to be moved across the stereo sound field in complex ways. Panning could be controlled via velocity, note number, or LFO control. The instrument provided a bank of 64 preset pan memories and 32 programmable locations for user-defined pan patterns. This feature added a new dimension to stereo imaging, allowing for sweeps and complex motions that enhanced the sonic animation of the performance.
Playability was enhanced through sophisticated keyboard dynamics control. Key velocity and after-touch pressure could be assigned to control pitch, filtering, AWM2 modulation level, and a range of AFM parameters. These parameters could be controlled in either a positive or negative direction. Velocity switching allowed different elements to be activated depending on the force of the key press. In addition to the standard pitch and modulation wheels, the Yamaha SY77 featured an extra assignable centre-detented wheel and several other assignable controllers, providing extensive expressive control.
The instrument included four internal digital signal processors for ambience, configured as two reverb effects and two modulation effects. The reverb effects allowed separate parameters to be programmed for the left and right channels. The effect processors could be interconnected in various parallel and series configurations, offering sophisticated processing options. The reverb library included 40 types of effects, ranging from hall and room reverbs to delays, tone controls, and distortions. The modulation effects included chorus, flange, symphonic, and tremolo.
The user interface was designed to manage the instrument’s complexity through a large 240 × 64 dot backlit liquid crystal display. The display showed multiple parameters simultaneously, with titles in large bold type and names spelled in full where possible. Flow diagrams and bar graphs were displayed in graphic form for instant recognition. A hierarchy of directory pages and a “jump” number system facilitated navigation. Data entry was supported by increment and decrement buttons, a numeric keypad, a data entry slider for absolute value changes, and a data wheel for relative value changes.
As a production tool, the Yamaha SY77 featured a multi-timbre mode allowing up to 16 different voices to be assigned to 16 different MIDI channels. A full-featured 16-track sequencer was built in, offering real-time, step-write, and punch-in recording capabilities. The sequencer supported quantization, extensive editing of note duration, velocity, and position, and track mixing. It could directly drive the multi-timbre setups, eliminating the need for external sequencing equipment. The instrument also included high-quality AWM2 drum and percussion samples that could be assigned to 61 keys.
Storage and connectivity were handled via a built-in 3.5-inch floppy disk drive, which could store both synthesiser and sequencer data. A backup function allowed for the creation of copies of important data. Synthesiser data could also be saved to compact Yamaha MDC64 type data cards, with a single card holding up to 64 kilobytes of data. The MIDI implementation was complete, with independently programmable receive and transmit channels, a program change assignment table, and bulk dump functions for data transfer.
The Yamaha SY77 featured dual assignable stereo outputs, designated as Group 1 and Group 2, each with its own front-panel group fader. Elements could be assigned to either or both groups, allowing for versatile mixing and real-time control. By combining output assignments with panning, each element in a four-element voice could appear separately at a different output. Different effects could be combined on each group output, and the group faders could be used to vary the effect complement in real time.
Features
- AWM2 (second-generation 16-bit Advanced Wave Memory) offers unmatched sample playback quality
- AFM (Advanced Frequency Modulation) provides a dramatic boost in FM sound quality and programming versatility
- RCM (Realtime Convolution & Modulation) achieves a new fusion of sample realism and the expressive power of FM
- Versatile 1, 2, or 4-element voice architecture and complex envelope generators for extensive sample layering capability
- Advanced digital filters for all-new dynamic timbre control
- Multiple complex programmable envelope generators
- Dynamic panning for enhanced sonic animation
- Programmable aftertouch and assignable controllers
- Four internal digital signal processors add essential ambience
- Comprehensive display and data entry controls for intuitive programming