DONUG was yesterday, Sept 10

[dewdrop_world]

The SuperCollider Day Of New UGens came and went yesterday with a few dozen new units released...

Enjoy!
hjh

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Dan Stowell UGen pack:

Mac downloads: http://tinyurl.com/2vsue5
Linux'n'Win can build from source - SVN info: http://tinyurl.com/35s55x

Based on a nice article on the chaotic physics of dry friction, I've put together a Friction UGen - it works as a nonlinear filter with plenty of potential for chaotic oscillations. It's particularly nice because it can turn very standard input (sine waves, whatever) into interesting chaotically-varying sounds.

1) InsideOut is simple - just inverts the positive and the negative parts of the wave separately - but I find it quite a useful distortion.

2) WaveLoss is a technique described by Trevor Wishart, in which tiny wave segments are simply replaced by silence. It can make sounds "evaporate".

3) Squiz is theoretically a simplistic pitch-shifter but the sound is weirder than that. It squeezes tiny wave segments in the time domain, leading to an odd filter/ring-mod sort of sound.

To recreate the sound of the ZX Spectrum 128 (classic 80s home computer) I wrapped up an emulation library (libayemu) as a UGen: AY.ar.

I've implemented a "Getenv" UGen which inputs an environment variable into the synth graph, i.e. takes a value from the server's shell execution environment, and outputs it as a numeric value. Why? It's useful in non-realtime batch processes: your synthdefs and OSC files, once written to disk, are essentially immutable. Input units like MouseX aren't useful in NRT mode. So this plugin allows a kind of "argument passing" into an NRT synthesis, without touching the OSC/synthdef files.

At the International Computer Music Conference this year, Federico Fontana presented his work on a new digital implementation of the Moog VCF. With his permission, I've ported his Java code over to C++ for SuperCollider. It sounds pretty nice and runs efficiently too. Efficiency fans please note: in my tests it uses about one-fifth of the CPU that bhob's MoogLadder.ar does, or one-third of the CPU that Josh's MoogVCF.ar does. Woo! (The three implementations all sound slightly different, so listen to them all if you're choosing which you want.)

The "Logger" and "ListTrig" UGens are a complementary pair of UGens about storing lists of values in a buffer. Logger writes values sequentially into a Buffer, but only when it receives a trigger signal. It can serve to record a log of event times, or values, etc. ListTrig takes a list of time offsets (in a buffer) and outputs trigger signals at the specified instants. Nice easy way to output an arbitrary pattern of triggers.

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Julian Rohrhuber:

I've implemented Emil Post's tag system algorithm as two new demand ugens that can be used for tracing intractable formal structures by sonification or just as a 'universal' sound generator.


Dtag(bufsize, v, axiom, rules, recycle, mode)
DbufTag(bufnum, v, axiom, rules, recycle, mode)


They can be downloaded from http://preview.tinyurl.com/ypcwv9 (sf sc-plugin page)



Emil Post's tag systems

Emil Post developed tag systems from the 1920s onward as an instrument of generalisation of symbolic logic, hoping that it would allow the study of properties like decidability and completeness. Due to their intractibility he gave up the attempt to prove their unsolvability. Minsky showed later that tag systems are recursively unsolvable, i.e. of equivalent to a universal turing machine [2].

This type of rewriting system consists of an initial string of symbols (axiom), a set of rules and a deletion number (v). In this implementation, Post's parameter m (size of the alphabet) is implicit is the number of letters in the alphabet used. The deletion number is a very interesting parameter, since it determines what part of the string forms the instructions for the process and what part is omitted. Post described three classes of behaviour: termination, periodicity, and divergence. "The classes with m = 1 or v = 1 or v = m = 2 were proven solvable. The case with m = 2, v > 2 he calls intractable, while he terms the cases m > 2, v = 2 as being of 'bewildering complexity'" [4].

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just a note, a while ago I added two UGens to the common distribution:

Dswitch

similar to Dswitch1, analogous to Pswitch. Embeds each demand stream before it takes in the next index.


IndexInBetween

analogous to Array:indexInBetween
finds the closest index in a sorted array and looks between this value and the next higher for the appropriate fractional index. In principle, this is the inverse of Shaper (but Shaper operates on wavetables only).

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Joshua Parmenter:

JoshUGens pack @ sc3-plugins

Mac downloads: http://tinyurl.com/2vsue5
Linux'n'Win can build from source - SVN info: http://tinyurl.com/35s55x

I have added a few new UGens to the JoshLib. Warp1MC and Warp2MC are similar to Warp1 and Warp2, except they can take and output multi-channel buffers. BFEncodeSter will encode a stereo signal to Ambisonics (with a width control). FMHEncode1 and FMHEncode2 are second order ambisonic encoders (decoders possibly on the way).

Also, BFEncode1 can now take ar or kr controls for inputs to azimuth, elevation and rho. This will eventually find its way into other encoders and decoders as well.

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Scott Wilson - BEASTMulch plugins:

PlayBufSendIndex and DiskInSendIndex - Like the regular versions but send the frame index as a /tr OSC message. Useful for making clocks, following in SoundFileViews etc.

VBAP Classes - An implementation of Ville Pulkki’s Vector Base Amplitude Panning for SC. Includes panner UGen and supporting classes.

CircleRamp - A wrapping linear lag UGen, similar to the normal Ramp. Useful for smoothing a control signal for panning around a ring, for instance.

PV_Decorrelate - Adds a different constant random phase offset scaled by the value of a scale argument to each bin. This is the same as PV_Diffuser but with the added scale factor. This version is adapted from techniques described in Kendall, G.S. 1995. "The decorrelation of audio signals and its impact on spatial imagery". Computer Music Journal 19(4): 71-87.

Download available at http://scottwilson.ca/site/Software.html

Consider the VBAP beta, at least for the moment.

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Fredrik Olofsson:

my contribution for this special day (sorry late - me on berlin time) will be the sid chip ugen...
http://www.fredrikolofsson.com/software/SID6581f.tar.gz

note that this is the 'faulty' version and i hope to release a correct one some other time. by faulty i mean not sounding the same as a real sid chip (actually most of my emu ugens ports might be wrong i realised but i had no means of comparing - just so you know). still this one is useful and fun sounding i think so enjoy.


i'd also like to plug a few ugens released this summer but never announced properly...

AY8910 - AY-3-891X Chip Sound Simulator
Astrocade - Sound Chip Simulator
Beep - Oldskool beep sound simulation
SN76489 - Sound Chip Simulator
the Bit package - BitAnd, BitXor, BitOr, BitNot, BitLeftShift, BitUnsignedRightShift, BitRightShift

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And, from Nick Collins (not the same as the circuit-bending Nick Collins - I've met them both and they don't look anything alike ), a bit of geek humor:

http://www.nabble.com/DONUG%3ADonug-tf4419822.html

Donug Toroidally constrained particle; trapped inside a supercollider!

Donug.ar(u,v,l,r,R, mul, add)

A particle moves constrained by a doughnut

Parametric form:

x= (R+l*cos(v))*cos(u);
y= (R+l*cos(v))*sin(u);
z= l*sin(u);

Some odd combination of AM, FM and output given by max(min((x+y)*(1+z),1.0),-1.0);


u- angle on x-y plane, z=0, 0-2pi
v- angle for elevation, 0-2pi
l- within ring current distance from centre (maximum of r)
r- radius of ring
R- distance of centre of ring from origin