MIDI
When the first MIDI specification was adopted in 1983, Passport put all of its development resources in this direction, licensing and developing a MIDI interface from Rittor Music in Japan and hiring Melcher to develop MIDI recording software. Composer Phil Stone was also hired at this time, first to develop audio for games on the Commodore 64, and then to port MIDI applications from Apple II to Commodore.
The first of these were MIDI/2 and MIDI/4, two-track and four-track MIDI sequencer/recorders for Apple II and Commodore 64 platforms, including OEM versions of MIDI/4 for Yamaha and Korg. These were introduced at the 1984 National Association of Music Manufacturers (NAMM) trade show, the first commercially-available MIDI sequeners in the United States. These were followed by Master Tracks in 1985, and Master Tracks Pro in 1986. This software pushed the Apple II to its limits, working with an optional card to extend the Apple's memory from 48K to 2M. In 1987, after Melcher left Passport, Master Tracks Pro was completely rewritten for the Apple Macintosh, and later the Atari ST series computers.
By this time, Passport Designs was attracting nationwide media attention for their products. An article in the May 28, 1984 issue of Newsweek described the upcoming MIDISOFT conference of music software publishers, and featured a photograph of Passport's demo room with a bank of MIDI-controlled synthesizers.
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