Sound Garden

(consider reading this document at http://ul.mantike.pro/sound-garden-0x2/README.html because GitHub parses AsciiDoc improperly)

What?

Sound Garden is a text based modular synthesis environment. If you ever considered text like this

.0625 .5 p 110 s * dup .5 t 0.0625 5 range 0.5 fb swap .125 t 0.0625 5 range 0.5 fb + .1 *

to be a valid musical notation and sound like this to be a subject of interest then you might find Sound Garden worthwhile having a look at.

Why?

There is Sporth, Extempore, SuperCollider, PureData, SonicPi, TidalCycles and other excellent mature environments out there, why to build own? Because I want to understand how audio synth works and true understanding comes as an ability to re-create subject from the scratch in a different form. More

How?

Continue reading, the rest of the document is Sound Garden manual.

Prerequsites

• Rust

Build & install

$ git clone https://github.com/ul/sound-garden-0x2.git
$ cd sound-garden-0x2
$ cargo install --path play_program --force
$ cargo install --path sound_garden_druid --force

(Inter)Faces of Sound Garden

Just a quick note before we start. Sound Garden is a set of libraries which fulfil various audio synth and livecoding needs and binaries which provide multiple layers of experience, from just producing sound when given a program to experiments with graphical tree-like representation. What you’ve built and installed in the previous section is the "simplest" interface which just plays programs and the "default" one which embodies Sound Garden aesthetics the most, but you are free to interact with it your way.

Run

First steps

Sound Garden is operated via simple concatenative stack-based language. The only type of element to be put on stack is a frame. Frame is a pair of amplitude values, one for the left channel and another for the right. Each sample (typically 44100 or 48000 times per second) Sound Garden executes your program against empty stack and sends top frame values to audio driver.

Let’s use the simplest Sound Garden interface to play tuning fork sound (please be sure to reduce your speaker volume before running it!):

$ echo '440 0 sine' | play_program

sine word corresponds to the stack operation which consumes frequency (440) and initial phase (0) from the top of the stack and puts back the next frame of sine wave.

Many words in Sound Garden has aliases. Some aliases are just shorter forms which make quick experiments easier for experienced users and some provide default value. For example s produces the same sine wave but always starts with phase 0:

$ echo '440 s' | play_program

To compose Sound Garden programs just slap them together separated by whitespace. This is why it’s called concatenative:

$ echo '440 s 0.5 *' | play_program

0.5 * will reduce our sine wave amplitude by half. Each channel, every sample.

Sound Garden is esoteric and sometimes cryptic but it’s very forgiving. Unknown words or stack overflows or underflow wouldn’t explode but will be ignored.

As you are free to put any values on the stack to be consumed by following ops (stack operations in Sound Garden lingo), you can easily make your sine wave more funky by modulating it with another wave:

$ echo '2 s 1 + 220 * s' | play_program

Take some time to meditate on what happens here.

That’s it about Sound Garden as a language (not really, it has few more tricks in its sleeve to be revealed in Templates section!). Please find list of available ops here.

Now its time to dive into Sound Garden as a livecoding environment.

Sound Garden Druid

SGD is a GUI interface to Sound Garden which resembles terminal modal editor. At the moment you have to run it from command line to provide it with the path to the tree and to configure other options.

$ sound_garden_druid ~/Documents/my_tree.sg

Editing commands

Table 1. Normal mode

Return	Commit.
\	Play/pause.
r	Toggle recording.
i	Insert mode.
I	Insert mode splash!
a	Move left and insert mode.
c	Cut & insert.
h	Left.
j	Down.
k	Up.
l	Right.
d	Delete node.
D	Delete line.
J	Move line and below down.
K	Move line and below up.
Alt+J	Move line and above down.
Alt+K	Move line and above up.
,	Move right of line left.
.	Move right of line right.
<	Move left of line left.
>	Move left of line right.
=	Cycle up / Increase by 1.
-	Cycle down / Decrease by 1.
/	List ops.
u	Undo
U	Redo
v	Toggle oscilloscope
Alt+=	Oscilloscope zoom in
Alt+-	Oscilloscope zoom out
Alt+h	Move node left.
Alt+j	Move node down.
Alt+k	Move node up.
Alt+l	Move node right.
H	Move line up.
L	Move line down.

Cycle commands commit changes immideately.

Table 2. Insert mode

Esc, Return	Normal mode.
<char>	Insert char.
Arrow keys	Move cursor.
Space	Move cursor left.
Backspace	Remove previous char.

Templates

Templates is syntactic sugar for abbreviating repetitive patterns. Template content is defined between square brackets followed by the template name. When Sound Garden encounters template name in the program down the line (including other templates), it substitutes that name with the template content. For example, the following

[ dup s swap c * ] yay
440 yay 220 yay +

will be expanded into

440 dup s swap c * 220 dup s swap c * +

Templates are livecoding-friendly, and replacing s in the template definition with t would produce expanded `t`s with the same identity as corresponding `s`s before, preserving phase.