a significant advance in technology. Almost every parameter can be controlled from an external control voltage. Computer-controlled instruments Buchla 300, 500, Touché (mid 1970s) In the mid 1970s, Don Buchla began experimenting with digital designs and computer-controlled systems. The results were the 500 series and the 300 series, both of which paired the new technology with existing 200 series modules to create hybrid analog/digital systems. The Touché was also the result of this research, . Buchla 400, 700, and MIDAS (1980s) Also in 1980s, Buchla released the 400 series and the 700 series software controlled instruments operated by MIDAS, a Forth language for musical instruments, and also equipped with MIDI. Buchla's unique synthesizer designs Buchla tended to not refer to his instruments as synthesizers, as he felt that name gives the impression of imitating existing sounds/instruments. His intent was to make instruments that create new sounds. This goal is evident in the omission of a standard musical keyboard on his early instruments, which instead used a series of touch plates that were not necessarily tied to equal-tempered tuning. He also used a different naming convention from most of the industry. For example, one of his modules is called a "Multiple Arbitrary Function Generator." These differences run deeper than nomenclature though. The Multiple Arbitrary Function Generator (or MARF) goes well beyond what a typical sequencer is capable of performing and is capable of acting as an envelope generator, LFO, CV selector, voltage quantizer or tracking generator. The MARF (Buchla model 248) is not to be confused with the modern Dual Arbitrary Function Generator (Model 250e) which features a different design. Buchla's instruments, such as the Music Easel (pictured), use a different method of timbre generation from Moog synthesizers. Moog units use oscillators with basic function generator type waveshapes and rely heavily on filtering with 24 dB resonant low-pass filters, while Buchlas are geared toward complex oscillators using frequency modulation, amplitude modulation, and dynamic waveshaping to produce other forms of timbre modulation. Many of Don Buchla's designs, including the Low-Pass Gates (later called Dynamic Managers) contain vactrols, photoresistive opto-isolator employed as voltage-controlled potentiometers, which can be used for a more "natural", typical Buchla sound. In December 2017, Arturia released a software/plugin emulation of the Music Easel, called the "Buchla Easel V", as part of the V collection. (late 1980s) Buchla Thunder, Buchla Lightning, Marimba Lumina By the late 1980s, Don Buchla had