Linux MIDI: A Brief Survey, Part 3

In this installment of my survey of Linux MIDI software, I profile various MIDI utilities, some of which have become indispensable components in my own Linux MIDI studio.

As I already have mentioned, the Old School MIDI studio was more hardware-centric than is today's software-based studio. Sequencers, synthesizers, samplers, MIDI-controllable mixers, MIDI channel routers and MIDI event processors all were available as useful boxes, lending greater flexibility to your studio setup. A common characteristic of most of these devices was the ability to dump the machine's internal settings and states into a type of MIDI message format called system exclusive. Sysex, as it's commonly called, is a way for MIDI equipment manufacturers to accommodate features specific to their designs; that is, sysex code is manufacturer-specific, so the sysex messages that work for a Yamaha synth are meaningless to a Roland synth. Going further, we find that sysex messages are device-specific as well, so the sysex calls to a Yamaha TX81Z are meaningless to my Yamaha TX802.

Sysex is especially important with regards to synthesizers and other "patch"-oriented devices. For example, my Yamaha DMP11 is an 8-channel MIDI controllable mixer with many features, some of which are accessible only by way of sysex commands. More importantly, the only way to back up my custom patches and settings for this mixer is by using sysex.

By using the sysex codes for a device, MIDI programmers are able to write a type of MIDI software known as a synth editor/librarian. Software of this type that attempts to address a variety of machines is known as a universal editor/librarian, and the devices addressed may include machines other than synthesizers. Writing a decent universal editor/librarian is a non-trivial task: the programmer must know the sysex codes for many machines, and he then must devise workable interfaces for each one. Because every synthesizer is a unique device, many interfaces to programs must be included in order to accommodate a wide range of features. These features include typical stages, such as envelope generators and oscillator definitions, as well as less common features, such as microtuning tables and keyboard scaling maps.