Kawai's second attempt to mass-produce a synth based on additive synthesis, after the K5. Released in 1996, the K5000 started with the same basic harmonic-generator architecture that the K5 used, in which harmonics are generated in blocks of 64 (including the fundamental). The K5000 adds considerably to the voice architecture, incorporating a set of sampled sounds which can be mixed with the additive waveforms (a concession to the difficulty that some performers had in getting the desired sounds using the additive method, as the K5000 was aimed in part at the workstation market). The ineffective filters on the K5 are replaced with four-pole resonant filters which can operate in either low pass or high pass mode, and a 128-band formant filter is added to the architecture. Nearly everything has a dedicated multi-segment envelope generator.
Unlike the K5, on the K5000 a single patch can use up to six harmonic generators, each tuned differently if desired. The K5000 also includes a set of onboard effects which can be added to a patch. For multitimbral operation, patches can be grouped into multi groups, as on the K5. The synth's memory capacity is given as 128 patches and 64 multi groups, but due to the variable number of harmonic generators that a patch can use, one patch may take up more than one memory slot, which means the actual number of patches that can be stored depends on the specific patches. Fortunately, the K5000 contains a built-in floppy disk drive, and patches can be stored and loaded directly to/from disk, in addition to using the disk drive to back up memory.
The user interface is improved over the K5. Instead of the cursor up/down/left/right buttons used to select patch parameters on a page of the K5's display, a set of function buttons on the sides and bottom of the display selects parameters to be edited. The display itself indicates what each button selects on a given display page. The display resolution is improved over the K5 and parameters have recognizable icons or text abbreviations, an improvement over the single-pixel flags used for some parameters on the K5 display. Harmonic editing is similar to the K5, in that the user can select a single harmonic to edit, or use an editing shortcut which allows adjusting a group of harmonics at once, such as all of the evens, all of the odds, all of the octave harmonics, etc.
Introduced in 1996, the K5000 was made in two keyboard versions and a rackmount version. The two keyboard variants were designated as the 'S' (for "synthesizer") and 'W' (for "workstation"). The W version came with an onboard sequencer and a set of sampled waveforms compatible with the General MIDI standard; it also contained more memory than the 'S' version. The 'S' version replaced the sequencer with a user-programmable arpeggiator and a set of 16 panel knobs known as the "macro knobs", which allowed real-time control over parameters; four of them were user-assignable on a per-patch basis. Originally, it was not possible to save edits made to a patch via the macro knobs, but this was fixed in a later OS update. The macro knobs were also available in an external knob box, which allowed the capability to be added to the W and rackmount versions; similarly, a memory expansion was available for the S version to give it the same memory capacity as the W version.
The K5000 was produced, in fairly small numbers, until the early 2000s. It was the last synth produced by Kawai before the company decided to exit the synth market.