The instrument
The SY-99 is an extended version of the SY-77, with 76 instead of 64 keys. Both are 16-voice polyphonic and 16-voice multitimbral music workstations. Their architecture combines AFM (Advanced Frequency Modulation) synthesis, AWM2 (Advanced Wave Memory 2) for ROM-based sample synthesis and their combination, RCM (Realtime Convolution and Modulation Synthesis).
The SY-99 has a keyboard with velocity sensitivity and aftertouch, a pitch wheel and two modulation wheels, expansion slots, a floppy disc drive, integrated effects and a sequencer. The SY77 and SY-99 were replaced by the W5 and W7 in 1994.
Details
The SY-99 and SY77 received the same extended FM engine. While the DX7 only had sine wave operators, a predefined feedback loop and 32 algorithms, there were now 16 waveforms per operator and 45 algorithms, as well as three freely definable feedback loops. After the FM section, a multimode VCF and a VCA are used, along with a 16-voice sample player section (Advanced Wave Memory AWM2) with the same VCF/VCAs. Both synthesisers have RCM (Realtime Convolution and Modulation) in common: Several arbitrary operators of the FM section can be dynamically modulated with the output of the AWM2 section. The wave ROM of the AWM2 synthesis has been doubled to 8MB compared to the SY-77 in order to improve the sounds. The sample RAM is organised into samples and sample maps. The internal 512kB memory can be expanded with up to five 512kB modules. The effects processor from the SPX1000 has been built in, with two stereo effects with 63 types. The sequencer has more songs and more memory available.