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Sequencing: Recording and Playing Back MIDI Performances
seq
Max has four objects for recording and playing back MIDI performances: seq, follow, mtr, and detonate. The “performance” can come from outside Max—from a MIDI controller, or another
MIDI application using the IAC Bus—or can be generated algorithmically within Max.
The basic sequencer in Max is seq, which records raw MIDI data received in its inlet from midiin or
midiformat, and can play the data back at any speed. The recording and playback process is controlled with messages such as record, start, and stop.
Sequences recorded by seq can be written into a separate file to be used again later. Under OSX,
“Max text file” and “Max binary file” are the two options for Save As... Under Windows, the
options are “maxb Files (*.mxb, *.pat, *.help)” and “TEXT Files (*.txt, *.pat, *.help, *.mxt)” When seq
receives a write message, it calls up the standard Save As dialog box. If the file is saved as text (by
choosing Max Format Text File from the Format pop-up menu in the Save As dialog box), it can be
edited by hand by choosing Open As Text… from the File menu. MIDI files can also be loaded
into seq with a read message.
follow
The follow object functions exactly like seq, but has the added ability to compare a live performance to the performance it has recorded earlier. follow can record not only raw MIDI data, but
also individual numbers such as note-on pitch values. You can step through the set of recorded
notes (or numbers) using the next message. Most interestingly, follow contains a score following
algorithm, activated by the follow message. follow will compare incoming numbers to those stored
in its recorded sequence. If an incoming number matches the next number in the recorded
sequence (or a nearby number, just in case the live performer makes a mistake), follow reports the
index of the matched note. The index can then be used to read other numbers from a table or coll
(providing an accompaniment to the live performer), or can be used to trigger any other process.
mtr
The mtr object is a multi-track sequencer that can record up to 32 individual tracks of numbers,
lists of numbers, or symbols. With such versatility, it is easy to record not only MIDI events, but a
wide variety of other messages. Tracks can be recorded, played, or stepped through using the next
message, either individually or collectively, and some tracks can be muted while other tracks con-
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