Akai DD1500

SYSTEM - MIDI - 22
Version 2.00 - March, 1996 Page 227
MIDI FUNCTIONS - TEMPO MAPS
The DD1500 allows you to create tempo maps for use when synchronising to MIDI
sequencers. The function is accessed in SYSTEM via the MIDI key (F3). You will see this
screen display:
The DD1500 can act as a master to a sequencer synced to the DD1500 using MIDI Time
Code (MTC) or MIDI clock with Song Position Pointer (SPP). Of these two options, MTC is
recommended for more accurate synchronisation as this is timecode via MIDI although if
your sequencer does not have MTC, MIDI clock with SPP is a perfectly good way to
synchronise your sequencer to the DD1500.
The principle behind a TEMPO MAP on the DD1500 is that the DD1500 can issue tempo
changes and changes in time signature to the sequencer as part of a project. Without
this, any variation of tempo in the recorded material on disk would not be passed to the
sequencer and the two machines would very quickly drift out of sync. By placing tempo
changes and time signature changes at the appropriate point, the sequencer can follow
the DD exactly. To achieve this, of course, your sequencer must be set to external sync so
that the DD1500 is in control of its tempo and time signature. THE DD1500 MUST BE SET
TO GENERATE MIDI SPP. This is done in the SYSTEM-TIME GENERATOR field.
The timecode generator must be switched on in the GENERATE field to drive the
sequencer (you could also use VIA EXT M/C KEY or VIA EXT TIME KEY so that you can
disable the sequencer locally from the DL1500). Also when working with MIDI sync in this
way, it is recommended you use the MIDI BBC (bars/beats/clocks) time display style set in
the TIME DISPLAY field.
NOTE: When MIDI B/B/C is selected as the TIME DISPLAY style, this will have
implications on functions elsewhere on the DD1500.
For example, if you use NUDGE, the DATA ENTRY +/- keys will nudge in beats and the
numeric keypad +/- keys will nudge in clocks (if you need more accurate nudge amounts,
select an H/M/S time display). The number of beats/bars you nudge by can be set in the
NUDGE SET page.
GOTO also changes slightly when MIDI B/B/C is selected in that you may go to a specific
bar/beat as well as to time and/or a locate memory.
You will also note that the PLAY TO, OVER and FROM work in bars and beats (the exact
amount may be set by pressing SHIFT+PLAY TO, OVER or FROM)
PRE-ROLL and CYCLE PRE-ROLL are also expressed in bars when MIDI B/B/C is
selected as the time display.