1/f noise pattern?

[James Harkins-2]

Do we already have a 1/f noise pattern that I overlooked?

If not, how about this?

hjh

// McCartney-Voss 1/f noise

Pmcvoss : Pattern {

var <>lo, <>hi, <>generators, <>length;

*new { |lo = 0, hi = 1, generators = 8, length = inf|

^super.new.lo_(lo).hi_(hi).generators_(generators).length_(length)

}

embedInStream { |inval|

var counter = 1,

maxCounter = 1 << (generators-1),

gens = { 1.0.rand } ! generators,

total = gens.sum,

i, new;

length.do {

inval = ((total / generators) * (hi-lo) + lo).yield;

i = counter.trailingZeroes;

new = 1.0.rand;

total = total - gens[i] + new;

gens[i] = new;

counter = (counter + 1).wrap(1, maxCounter);

}

^inval

}

}

: H. James Harkins

: jamshark70@...

: http://www.dewdrop-world.net

.::!:.:.......:.::........:..!.::.::...:..:...:.:.:.:..:

"Come said the Muse,

Sing me a song no poet has yet chanted,

Sing me the universal."  -- Whitman

[Nathaniel Virgo-2]

That looks good and would be handy - very similar to one I have in my (currently still private) lib that I called Ppink.

It may also be helpful to put a simple low-pass filter on the result (e.g. value = x*value + (1-x)*previous_value) ) simply because the Voss-McCartney method produces a bit too much very high end, which makes the individual values a bit too un-correlated to each other.

(also an LFPink UGen would be handy for me too)

Nathaniel

2008/7/22 James Harkins <jamshark70@...>:

Do we already have a 1/f noise pattern that I overlooked?

If not, how about this?

hjh

// McCartney-Voss 1/f noise

Pmcvoss : Pattern {

var <>lo, <>hi, <>generators, <>length;

*new { |lo = 0, hi = 1, generators = 8, length = inf|

^super.new.lo_(lo).hi_(hi).generators_(generators).length_(length)

}

embedInStream { |inval|

var counter = 1,

maxCounter = 1 << (generators-1),

gens = { 1.0.rand } ! generators,

total = gens.sum,

i, new;

length.do {

inval = ((total / generators) * (hi-lo) + lo).yield;

i = counter.trailingZeroes;

new = 1.0.rand;

total = total - gens[i] + new;

gens[i] = new;

counter = (counter + 1).wrap(1, maxCounter);

}

^inval

}

}

: H. James Harkins

: jamshark70@...

: http://www.dewdrop-world.net

.::!:.:.......:.::........:..!.::.::...:..:...:.:.:.:..:

"Come said the Muse,

Sing me a song no poet has yet chanted,

Sing me the universal."  -- Whitman

[Julian Rohrhuber]

>Do we already have a 1/f noise pattern that I overlooked?
>
>If not, how about this?


nice.

note that according to the post reform pattern paradigm, lo, hi
should be able to be patterns, and length should be sent the value
message.

also you may want to use newCopyArgs for a simpler and faster init.

>hjh
>
>// McCartney-Voss 1/f noise
>
>Pmcvoss : Pattern {
> var <>lo, <>hi, <>generators, <>length;
> *new { |lo = 0, hi = 1, generators = 8, length = inf|
>
> ^super.new.lo_(lo).hi_(hi).generators_(generators).length_(length)
> }
>
> embedInStream { |inval|
> var counter = 1,
> maxCounter = 1 << (generators-1),
> gens = { 1.0.rand } ! generators,
> total = gens.sum,
> i, new;
>
> length.do {
> inval = ((total / generators) * (hi-lo) + lo).yield;
>
> i = counter.trailingZeroes;
> new = 1.0.rand;
> total = total - gens[i] + new;
> gens[i] = new;
>
>
> counter = (counter + 1).wrap(1, maxCounter);
> }
> ^inval
> }
>}
>
>
>
>: H. James Harkins
>
>: <mailto:jamshark70@...>jamshark70@...
>
>: <http://www.dewdrop-world.net>http://www.dewdrop-world.net
>
>.::!:.:.......:.::........:..!.::.::...:..:...:.:.:.:..:
>
>
>"Come said the Muse,
>
>Sing me a song no poet has yet chanted,
>
>Sing me the universal."  -- Whitman

--





.

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