Understanding Streams, Patterns and Events - Part 6

Parallel Patterns

Ppar

The Ppar pattern allows you to merge multiple event streams to play in parallel.

Ppar is a ListPattern and so like most ListPatterns it takes two arguments, a list of event patterns to play in parallel and a repeats count.

Ppar's child patterns must be event patterns. Using value patterns in a Ppar is an error because value patterns contain no duration data.

A Ppar is done when all of its subpatterns are done.

(

Ppar([

Pbind(\dur, 0.2, \midinote, Pseq([62, 65, 69, 72], inf)),

Pbind(\dur, 0.4, \midinote, Pseq([50, 45], inf))

]).play

)

(

// Ppars can be nested

Ppar([

Pbind(

\dur, Prand([0.2, 0.4, 0.6], inf),

\midinote, Prand([72, 74, 76, 77, 79, 81], inf),

\db, -26,

\legato, 1.1

),

Pseq([

Pbind(\dur, 3.2, \freq, Pseq([\rest]) ),

Prand([

Ppar([

Pbind(\dur, 0.2, \pan, 0.5, \midinote, Pseq([60, 64, 67, 64])),

Pbind(\dur, 0.4, \pan, -0.5, \midinote, Pseq([48, 43]))

]),

Ppar([

Pbind(\dur, 0.2, \pan, 0.5, \midinote, Pseq([62, 65, 69, 65])),

Pbind(\dur, 0.4, \pan, -0.5, \midinote, Pseq([50, 45]))

]),

Ppar([

Pbind(\dur, 0.2, \pan, 0.5, \midinote, Pseq([64, 67, 71, 67])),

Pbind(\dur, 0.4, \pan, -0.5, \midinote, Pseq([52, 47]))

])

], 12)

], inf)

], inf).play;

)

Ptpar

The Ppar pattern starts all of its subpatterns at the same time.

Ptpar pattern includes a start time parameter before each subpattern which allow the subpatterns to

be started at some time delay within the pattern. The start time is given in beats.

(

var makePattern, durpat;

durpat = Pseq([ Pgeom(0.05, 1.1, 24), Pgeom(0.5, 0.909, 24) ], 2);

makePattern = { arg note, db, pan;

Pbind( \dur, durpat, \db, db, \pan, pan, \midinote, Pseq([note, note-4], inf) );

};

Ptpar([

0.0, makePattern.value(53, -20, -0.9),

2.0, makePattern.value(60, -23, -0.3),

4.0, makePattern.value(67, -26, 0.3),

6.0, makePattern.value(74, -29, 0.9)

], inf).play;

)

The time argmuents are sent the 'value' message when the Ptpar pattern is started, so you may use functions to specify the times.

(

var makePattern, durpat;

durpat = Pseq([ Pgeom(0.05, 1.1, 24), Pgeom(0.5, 0.909, 24) ], 2);

makePattern = { arg note, db, pan;

Pbind( \dur, durpat, \db, db, \pan, pan, \midinote, Pseq([note, note-4], inf) );

};

Ptpar([

{ 0.0 }, makePattern.value(53, -20, -0.9),

{ 8.0.rand }, makePattern.value(60, -23, -0.3),

{ 8.0.rand }, makePattern.value(67, -26, 0.3),

{ 8.0.rand }, makePattern.value(74, -29, 0.9)

], inf).play;

)

FilterPatterns and transformation

FilterPatterns take an existing pattern and apply some modification to its properties.

Padd, Pmul, Pset, Pstretch

There is a simpler way to write the modal transposition example given in part 5. In fact the earlier examples are setting the values of mtranspose and ctranspose which is not the best way to change those variables, because it wipes out any modifications to them by parent patterns. It is better to take the current value of those properties and add a value to them. The Padd filter takes the current value of a property and adds a value to it.

(

// modal transposition

var pattern;

// define the basic pattern

pattern = Pbind(

\dur, 0.15,

\degree, Pseq([ Pshuf(#[-7,-3,0,2,4,7], 4), Pseq([0,1,2,3,4,5,6,7]) ], 1)

);

Pseq([

pattern, // untransposed

Padd(\mtranspose, 1, pattern), // modal transpose up 1 degree

Padd(\mtranspose, 2, pattern) // modal transpose up 2 degrees

], inf).play

)

Similarly, Pmul multiplies the current value of a property by a value.

Pset sets the property to a value.

Pnot does a logical negation of a property with a Boolean value.

In order to process duration correctly Pstretch should be used.

(

// beat stretching using Pstretch

var pattern;

// define the basic pattern

pattern = Pbind(

\dur, 0.15,

\degree, Pseq([ Pshuf(#[-7,-3,0,2,4,7], 4), Pseq([0,1,2,3,4,5,6,7]) ], 1)

);

Pseq([

pattern, // normal

Pstretch(0.5, pattern), // stretch durations by a factor of 1/2

Pstretch(2.0, pattern) // stretch durations by a factor of 2

], inf).play

)

Paddp, Pmulp, Psetp, Pstretchp

In fact there is an even shorter version of the modal transposition example. Paddp reads one pattern to get values for adding to a property and plays the second pattern once through modified with each new value.

(

// modal transposition

var pattern;

// define the basic pattern

pattern = Pbind(

\dur, 0.15,

\degree, Pseq([ Pshuf(#[-7,-3,0,2,4,7], 4), Pseq([0,1,2,3,4,5,6,7]) ], 1)

);

Paddp(

\mtranspose, // property to be modified

Pseq([0,1,2], inf), // a value pattern as a source of values for adding to mtranspose

pattern // the pattern to be modified

).play

)

Nested modifications:

(

// modal transposition

var pat1, pat2;

// define the basic pattern

pat1 = Pbind(

\dur, 0.15,

\degree, Pseq([ Pshuf(#[-7,-3,0,2,4,7], 4), Pseq([0,1,2,3,4,5,6,7]) ], 1)

);

pat2 = Paddp(

\mtranspose, // property to be modified

Pseq([0,1,2]), // a value pattern as a source of values for adding to mtranspose

Ppar([

pat1,

Padd(\mtranspose, -3, pat1), // down a 4th

Padd(\mtranspose, 2, pat1) // up a 3rd

])

);

Pseq([

pat1, // unmodified pattern

pat2, // parallel sequence

Pstretch(1.5, pat2) // parallel sequence stretched by 3/2

], inf).play

)

Another example using Paddp:

(

var chord;

chord = Prand([[53, 58, 64],[53, 60, 64],[57,60,65]]);

Paddp(\ctranspose, Prand([-1,0,2,4,5], inf),

Ppar([

Pbind( // melody part

\dur, Prand([0.2, 0.4, 0.6], inf),

\midinote, Pxrand([71, 72, 74, 76, 77, 79], 10),

\db, -26,

\legato, 1.1

),

Pbind( // harmony part

\pan, 0.4,

\dur, Pseq([0.1, 0.5, 0.4, 0.6], 4),

\midinote, Pseq([chord,\rest,chord,\rest], 4)

),

Pbind( // bass part

\pan, -0.4,

\dur, 0.4,

\midinote, Pseq([38, 45, 38, 36], 4)

)

])

).play

)

(

// chromatic transposition

var pattern;

// define the basic pattern

pattern = Pbind(

\dur, 0.1,

\degree, Pseq([0,1,2,3,4,5,6,7])

);

Paddp(

\ctranspose, // property to be modified

Pseries(0,1,12), // a value pattern as a source of values for multiplying with ctranspose

pattern // the pattern to be modified

).play

)

(

// beat time stretching

var pattern;

// define the basic pattern

pattern = Pbind(

\dur, 0.1,

\degree, Pseq([0,1,2,3,4,5,6,7])

);

Pstretchp(

Pseq([1,2,3], inf), // a value pattern as a source of values for multiplying with stretch

pattern // the pattern to be modified

).play

)

Pbindf

Pbindf is like Pbind except that it merges all the bound symbols into events that it gets from a subpattern. It takes the same initial arguments in pairs as Pbind does, with an additional pattern to be modified as the last argument.

(

var pattern;

pattern = Pbind( \midinote, Pseq(#[60, 62, 64, 65, 67, 69, 71, 72]) );

Pseq([

Pbindf(pattern, \legato, 0.1, \dur, 0.2),

Pbindf(pattern, \legato, 1.0, \dur, 0.125),

Pbindf(pattern, \legato, 2.0, \dur, 0.3)

], inf).play

)

Patterns can be used as the arguments to Pbindf.

(

var pattern;

pattern = Pbind( \midinote, Pseq(#[60, 62, 64, 65, 67, 69, 71, 72, 74, 76, 77, 79]) );

Pseq([

Pbindf(pattern,\legato, 0.1, \dur, Pgeom(0.3, 0.85, inf)),

Pbindf(pattern,\legato, 1.0, \dur, Pseq([0.3, 0.15], inf)),

Pbindf(pattern,\legato, 2.0, \dur, Pseq([0.2, 0.2, 0.4], inf))

], inf).play

)

To go to the next file:

Streams-Patterns-Events7