How to play Sound in Pharo

This is a brief post on how to load the sound package, enable it and play some sound samples in Pharo 9.0. For Pharo 9.0, we fixed the sound support by refactoring and using SDL2 for enqueuing the playback of sound samples. The current version only supports sound playback, but it does not support yet sound recording from a microphone.

Downloading a clean Pharo 9 image and VM

Some users have reported on following these instructions on older of Pharo. In case a weird problem is obtained such as “Failed to open /dev/dsp”, we recommend to download the latest Pharo 9 image and headless virtual machine. This image and VM can be downloaded through the Pharo Launcher, manually through the files server in the Pharo website, or by executing the following Zeroconf bash script in Linux or in OS X:

curl https://get.pharo.org/64/90+vmHeadlessLatest | bash

Loading the Sound Package

The first step required to be able to play sound in Pharo 9.0 is to load the Sound package. The Sound package is not included by default in the main Pharo image, so it has be loaded explicitly. The following Metacello script can be used for loading the Sound by doing it in a Playground:

Metacello new
baseline: 'Sound';
repository: 'github://pharo-contributions/Sound';
load

Setting for enabling Sound

Loading the sound package is not enough to be able to play sound in Pharo. In addition to loading this package, it is required to enable sound playback under the Settings browser. After the Sound package is loaded, under the Appearance category, a setting named “Sound” appears with a checkbox that needs to be enabled to activate sound playback.

Examples for playing Sound samples

The Sound package bundles several software based synthesizers, so it is not required to load explicit wave (.WAV) files in order to play samples and music for testing it. The following is an example script for playing major scale with an electric bass patch that is generated through FM synthesis:

(FMSound lowMajorScaleOn: FMSound bass1) play

Since we are inheriting this package from older versions of Pharo, we do not comprehend yet all of the features for sound and music synthesis that are provided by this package. However, we recommend to look on the existing instrument examples that are present in the class side of the AbstractSound and FMSound classes.

Wave samples (.wav) from disk can be loaded and played through the SampledSound class. For example, if we have a sound sample in a file named test.wav, in the same folder as the image, we can load it and play it with the following script:

(SampledSound fromWaveFileNamed: 'test.wav') play

The most complicated and spectacular example that is bundled in the Sound package is a playback of the Bach Little Fugue with multiple stereophonic voices. This example can be started with the following short script in a Playground:

AbstractSound stereoBachFugue play

If you want to

If you want to contribute…

The sound package is hosted on http://github.com and you can really help us to improve it.

Metacello new
  baseline: 'Sound';
  repository: 'github://pharo-contributions/Sound';
  load

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