The
"Time base" dialog
To
change the metronome valu
e,
type cmd-t. The "
Time
base
"
and "
Metronome"
dialogs are displayed (see Fig.18).
Fig.18
"Time base"and "Metronom" dialogs
There
are two ways of adjusting the clock. The "
Metronom"
dialo
g
deals with conventional metronome settings, i.e. "mm = 400" means 400 ticks per
minute. You may change this value, for instance, to 345.08. Changes are
reflected in the "
Time
base
"
dialo
g.
Now it tells "8627 ticks in 1500 seconds", which actually means the same as
"mm = 345.08". If you need to set the time base accurately, type directly the
numbers of ticks and/or seconds. Whenever you change values, BP2 finds the
simplest integer numbers yielding the expected integer ratio. The "Metronom"
dialog may display a rounded value which will not affect accuracy since BP2
actually uses the integer ratio displayed on the "Time base" dialog.
A
very accurate clock is needed to superimpose BP2 items on a given (digitized)
sound track. In addition, synchronisation tags (see §6.6) or Apple Events
(§6.7) make it possible to start items on precise dates determined by the
environment.
The
"Time base" dialo
g
contains boxes allowing the definition of
three
independent cycles
that produce
ticks
on marked beats. When "Play tick
s"
is checked, ticks become audible. Ticks may be mapped to any MIDI key, channel
and velocity. For each cycle, first adjust the cycle duration (1 to 40 beats),
then check the boxes of all beats that need to be stressed by a tick. Each
cycle may run at a speed differing from that of the basic clock if its speed
ratio is not 1/1. A typical example is given in the time base saved as
"-tb.slowshif
t"
which may be opened (cmd-o) when the "Time base" dialo
g
is in front.
It
is possible to define each tick of the time base individually. Click any
square of a tick cycle with the 'option' key down to display the "
Tick
settings
"
dialo
g
(Fig.19).
Fig.19
"Tick settings" dialog The
ON/OFF button determines whether the beat should be audible. If "Use default
settings" is checked then the tick will be heard on the default channel, key
and velocity of its cycle. If "Use special settings" is checked, then these
parameters are specified individually as shown Fig.19. The "Capture setting
s"
button makes it possible to pick up these parameters from a MIDI device. It's
a good idea to send ticks to a MIDI sample
r
with percussive or fancy sounds.
A
tick cycle may be captured as a MIDI stream and pasted to a sound-object
prototype (see §2.3.3). Ultimately, if the sound-object is played alone
it can further be saved to a MIDI fil
e
(see §14.1). This is a good trick to use tick cycles created by BP2 with
other MIDI software.
The
time base continues ticking, if instructed to do so, while BP2 is improvising
items. You may check this with examples contained in "-da.tryTick
s".
Note that in
smooth
time
(see §9) beats may become irregular, depending on time streaks created by
the musical item. Try "-gr.tryTimePattern
s"
to hear the difference. These superimposed ticks are neither saved in MIDI
files nor interpreted as Csound events.
Different
settings of the time base have been saved as -tb.<name
>
files representing the most popular
talas
of North Indian classical music.
The
time base allows an
accurate
transcription of durations
when notes are entered from the MIDI keyboard (typing cmd-j, see §1.5).
When "Play tick
s"
is checked, durations are transcribed following the
period
notation
(see §1.12.1).