Roland MKS-20
Roland's structured/adaptive synthesis (SAS) has been described as a "sophisticated re-synthesis technique which involves a highly accurate computer analysis of 'real' sounds, from which a near replica can be synthesised.
"[1] Roland engineers created samples of each of the 88 keys of various grand pianos, played at 128 different velocities (i.e. everything from very soft to very loud), and then did analysis of the waveform changes.
[4]: 5 It weighs 8 kg (17 lb 10 oz) and uses the standard 19-inch rack size, occupying 2U with a nominal height of 90 mm (3.5 in).
[9] The settings offer keyboard touch response changes, which are called A, B, C and D. B is the default value, under which the shift in dynamics and harmonic structure increases in a linear way with the amount of velocity applied to a key.
[10][11] That technology was extended to home digital pianos in 1987 (HP-5600S, -5500S, -4500S, and -3000S),[12] all 88-key units which were distinguished by built-in speaker configuration and finish, weighing between 39 and 93 kg (86 and 205 lb) for the -3000S and -5500/5600S, respectively, including the stand for the 5500/5600.
In addition to the equalizer, chorus and tremolo, the MK-80 also featured a stereo phaser effect, implemented using two IR3R05 OTA chips, the same ones used in the JX-8P synthesizer.
While having different configuration and ROM content, most models featuring structured/adaptive synthesis use a similar electronic circuit to generate sounds, on a PCB called CPU-B board.
[21] The CPU-B board is based around an Hitachi HD6303R CPU, which interacts with three custom chips of the gate array type, manufactured by Fujitsu.
The MKS-20 offered "...more than 30 keyboard 'zones' differentiated not just by pitch and brightness, but also by individual formant structures and string enharmonicities", creating a piano sound that was "...far superior to any straightforward sample-replay system" available in 1986.
[25] Pianoteq software (2006) and the Roland V-Piano (2009) take a similar approach as SAS by using computer models of physical instruments, rather than relying on samples.
[26][27] In 2016, Fait Clic released a Windows-based Virtual Studio Technology (VST) recreation of the MKS-20, called MKS-20Vst for Windows.
[28] In 2017, VGSG Music released a digital version called iKS20 that makes MKS-20's sounds available on Yamaha's MOXF, MOTIF XF, MONTAGE and MODX synthesizers.
Additional requirements include the installation of the Yamaha FL1024M 1GB Flash Expansion Board for the MOXF and MOTIF XF.
The Keyscape virtual instrument uses multisampled sounds and requires 77 GB to download or the purchase of boxed USB drives.
[31] In 2025, the custom chips used in the MKS-20 and other SAS models have been reverse-engineered, and a very accurate open source emulation has been added to MAME.
