transport-controls

transport controls

Figure 1 summary

• default tempo 240 bpm
• send out global data

start and stop

Inlet [inlet start-stop] receives a Boolean value, 1 to start the metro in the masterclock and 0 to stop it. Each time this toggles the default period is broadcast and the clock period refreshed. A toggle input box on the transport GUI sends this value. Also on the transport GUI is a bang button which is received by [r zero] to set the time counter back to 0.

output values

Four different messages are continuously sent by the masterclock, [s trig] emits bangs on every single beat of the metro, [s scoretime] sends a float representing the time for the conductor of the score, [s drumtime] is always a beat ahead of the scoretime [s synthtime] moves at half the regular rate. We don't use all these time values in this composition but this is a useful way to output time values, so that score changes can be processed one step ahead of the main timeline.

Figure 1: A1-transport-controls

A1-transport-controls.pd

timebase

Figure 2 summary

• start now
• define order
• counter
• synth is half speed
• synth first in order
• drums next in order
• scoretime next in order
• send bangs

metronome

The metro is always started by default here, you can remove the loadbang if you don't want the piece to start automatically. The metro period is set from the middle inlet and if anything is received on the right inlet the counter is set to zero.

late and early beats

You can see how time is made a beat earlier by taking its value from after the [+ 1] instead of from the float box. You could chain these or add arbitrary increments or decrements to the timeline. If you want a part to play 4 beats ahead add [+ 4] before its time inlet. Beare of negative times that won't exist when the timebase is zero.

dividing time

Dividing time is as simple as using [/]. But this raises interesting points to do with number lines and quantisation. A timeline that is multiplied by an amount is stretched or shrunk like a rubber band. If you are using select statements that work on integer beat marks then you need to re-quantise with [int] and [change]. If a timeline is doubled then it loses half its resolution, but if it is squashed to half then its resolution would double, if it were say audio tape, however it halves. If we had an integer timeline ${1, 2, 3 ...}$ and divide by 2 we get ${0.50, 1, 1.50, 2 ...}$, some of the values have become non-integer. Although we can make any floating point number that is a function of a periodically updated timebase it is sampled at the rate of the timbase itself, which is when message events occur. These two things, the value and the time it is sent, are separate things. Using a rounding process two notes must now fall into each event slot (pigeonhole principle). Going the other way let's take a timeline ${1, 2, 3, 4}$ and multiply it by 3. We get ${3, 6, 9, 12}$ You can build up sophisticated rythmns using [mod], [int], [change] and [div], but it's recommended that if you study this be aware it depends on the implementation of [int], there are other ways of rounding numbers that will break your compositions if you translate them or the definition of [int] changes.

Figure 2: A2-masterclock

A2-masterclock.pd