Our Word For The Day “Interleaving” prompted reader Jim B. To send in the following technical information:
Reader Richard P. saw our Word For The Day “MIDI Mode” in which we mentioned the following:
| “MIDI Mode” – One of several ways in which a device can respond to incoming MIDI information. There are two parts to each mode, one defining whether it is monophonic or polyphonic, and the other determining if it is multitimbral or not. Four modes are included in the MIDI spec, and two others, Multi Mode and Mono Mode (for MIDI guitar) were developed later…(etc. etc. etc.) 4. Omni Off/Mono – Device responds to MIDI data only on one particular channel, and is monophonic. “Mono Mode” – Used for MIDI guitar applications, Mono Mode is an expanded version of Mode 4, allowing for six Omni Off/Monophonic channels to be used at once, one for each string of the controller. This allows for better tracking, independent pitch bend per channel, and a separate sound or patch assignment per channel.” |
Richard asks:
| “I have always thought that the original Mode 4 in MIDI Spec 1.0 _was_ Mono mode, and have been teaching it that way since 1986. I don’t have my Spec book handy, but I believe that it states that Mode 4 instruments respond to a range of channels numbered consecutively upwards from a base channel. I believe that the Casio CZ-101 and Oberheim Xpander were both early examples of Mode 4 instruments. Please correct me if I’m wrong.” |
Thanks for your message Richard! We don’t have a copy of the Spec in front of us either (sorry), but if memory serves, Mode 4 does not necessarily reference more than one MIDI channel simultaneously, although in practice most, if not all, manufacturers implement it that way. You are correct in listing the CZ101 and Xpander as early examples of multi-channel Mode 4 operation, although this was probably the result of polyphony limitations when in multi-timbral operation, rather than a real desire for true Mode 4 operation.
Regardless, it has become accepted and common usage to refer to Mode 4 as Mono Mode, and to assume multi-channel operation. The issue is pretty much moot these days.
By the way, a good reference Web site for all issues pertaining to the technical aspects of MIDI is Jeff Glatt’s MIDI Information page.