According to Akai's S612 owner's manual, these are it's features:
"Realization of super-high-quality sound by 12-bit sampling technology.
6-voice polyphonic performance is possible in connection with MIDI keyboards, synthesizers, sequencers and many others.
Realization of sampling time up to 8 seconds (@ 4 kHz, 1 second @ 32 kHz).
A short sampled sound can be continuously played with no time restrictions and without sounding awkward. The S612 contains an advanced scanning mode system with 'looping' and 'alternating' modes. [This mode plays continuously through the sample, alternately playing it frontwards and then backwards]
The best splicing point for 'looping' can be selected instantly by the automatic splicing system.
A splicing point can be selected at any time by switching to the manual splice mode.
Because the starting or ending point of the sample can be selected at any time, it is possible to play the sound after elimination of an undesired portion of the sample. It is also possible to reproduce the sample in reverse.
It is possible to overdub samples and accumulate various sounds infinitely.
The S612 is equipped with an LFO (sine wave only), which can add vibrato effects with a delay.
The S612 is also equipped with continuous variable-pass low-pass filters for adding a milder touch to samples.
2.8 inch sample disks can be used for data files. "Save" and "load" procedures are extremely quick. You can continuously build your own tone sample library with the specially designed Sampler Disk Drive MD280. [You can also download samples via SYSEX to a MIDI librarian.]
Any type of sound can be tuned to a designated pitch by transposing it by a half step. This can also be done by tuning +/- 100 cent. The sound can then be stored on disk.
The S612 is rack mountable (EIA/2U) for excellent operation in the studio as well as at live performances. It can be handled with ease and offers astonishing performance."
The Akai S612 (along with most of Akai's sampler technology) was designed by David Cockerell, formerly with EMS and Electro-Harmonix. He joined Akai in 1985 when Electro-Harmonix went under. While at EH, he had been working with digital effects processors including digital delays. He designed a digital delay machine that could capture a sound/sample which could be triggered. He developed this technology into a one-shot sampler. When he went over to Akai, this became the S612. David still leads Akai's London Research and Development team.