A series of Sample playback synths produced by E-mu Systemsfrom 1989 through about 2003. There were about 20 models in all; most were not named Proteus but they shared a basic architecture. Most were packaged as 1U high rackmount units, although a few models were built as full keyboards.
The series began with the Proteus/1 synth of 1989. It was loaded with samples in ROM, drawn from E-mu's library of sounds that it had built to sell to Emulator owners. The sounds were basic rock and pop sounds -- guitars, basses, (non-synth) keyboards, drums. This was followed shortly by the Proteus/2, loaded with orchestral instrument sounds, the Proteus/3, with ethnic instrument sounds, and the Procussion, with drum sounds. All four of these models shared the same hardware; they were identical except for the sample ROM and panel graphics. Some basic changes to the hardware design resulted in the "XL" models which contained two or more of the ROM sets, and expanded patch memory. The sound shaping capabilities of these modules was limited, as they lacked any sort of filters.
The hardware developed for the Morpheus in 1993 was used to develop a second series of sample playback synths. These units can be distinguished by a power switch at the far right with a large data entry knob just to its left. This line included the Orbit 9090 (electronica-centric samples), the Planet Phatt (hip-hop / acid jazz), the Carnaval (Latin sounds), and the Vintage Keys (samples of vintage electronic instruments). These corrected one of the main drawbacks of the first series, in that a VCF-like capability was available, providing more possibilities for altering the sound of the built-in samples.
The third series began with the introduction of the Proteus 2000 in 1999. This series is distinguished externally by the five parameter entry / select knobs to the left of the display screen, easing somewhat the task of patch editing (the previous series all used a one-knob interface and had the reputation of being difficult to edit). About 10 modules were released in this series, including the Audity 2000 (named after a legendary E-mu prototype that never went into production), Orbit 3, Planet Earth, Mo' Phatt, Xtreme Lead, and Vintage Pro. The Proteus 2500 was a 4U high rack version with a greatly expanded user interface for easier editing and real-time control. Four models were also produced in keyboard versions, all using the same hardware: the XL-6 Xtreme Keys, the MK-6 Mo' Phatt Keys, the PK-6 Proteus Keys, and the Halo which was marketed under the Ensoniq name. All of these third-series Proteus synths were equipped with four ROM slots; each came with one slot loaded from the factory depending on the model, and the other three could be loaded with expansion cards containing sounds from other models, making "hybrid" models possible. A notable feature of this series was that they were 32-part multitimbral; to make this actually work, they contained 'A' and 'B' MIDI interfaces, with the 'B' interface being treated as logical channels 17-32 internally. Production of all Proteus hardware models ceased by 2005.
The final product in the Proteus line was the Proteus X soft synth, which operated as a VST plug-in or a stand-alone application. In order to authorize it, it required the computer to be equipped with an E-mu sound card or MIDI interface, which limited its sales.