Difference between revisions of "Lab1 Making FX in Pd"

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In this lab, we will build two effects from scratch: a tremolo effect, and a ring modulator (both with stereo output). For the more brave, we will guide you to the construction of a simple (mono) compressor.  
 
In this lab, we will build two effects from scratch: a tremolo effect, and a ring modulator (both with stereo output). For the more brave, we will guide you to the construction of a simple (mono) compressor.  
  
In general, even though it is a good idea to first try the effects on your own computer (provided you have Pd installed) using audio files as input sources, we recommend to try your effects directly on CCRMA Satellite (first using a recorded sound source) when possible. If you are going to start trying out your effects first with a recorded sound and have not brought any sound file(s) with you, you can search and download (under a Creative Commons Licencs) some clean guitar sounds from Freesound [http://www.freesound.org].
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In general, even though it is a good idea to first try the effects on your own computer (provided you have Pd installed) using audio files as input sources, we recommend to try your effects directly on CCRMA Satellite (first using a recorded sound source) when possible. If you are going to start trying out your effects first with a recorded sound and have not brought any sound file(s) with you, you can search and download (under a Creative Commons License) some clean guitar sounds from Freesound [http://www.freesound.org].
  
== Tremolo Effect ==
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== Effect 1: Tremolo ==
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 +
A first step is to have a clear idea of the overall operational structure of the effect. The actual realization and/or parameter tuning can of course vary depending on your preferences. For the case of a tremolo, the structure is pretty simple. We have seen that a tremolo effect is based on rapidly varying the amplitude of the input signal.
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Changing the amplitude can be easily achieved by multiplying the signal by a number. This can be dong by so is the '''mull~''' block:
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[[File:mul1.JPG]]
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 +
 
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The idea is to generate an automatically changing
  
A first step is to have a clear idea of the overall operational structure of the effect. The actual realization and/or parameter tuning can of course vary depending on your preferences.
 
  
 
[[Category:Stompbox_2011]][[Category:PID]]
 
[[Category:Stompbox_2011]][[Category:PID]]

Revision as of 14:08, 16 July 2011

Lab 1: Making FX in Pd on CCRMA Satellite

by Esteban Maestre

For this lab you need your Satellite CCRMA kit, a computer to program it, and some headphones with a mini 1/8" stereo jack. For applying created effects to a real instrument, you will also need your instrument with an appropriate instrument-kit audio cable (this will depend on the audio digital interface used with CCRMA Satellite), and a kit-headphones (this will also depend on the audio digital interface used).

Introduction

As you might have perceived from the early illustrative examples shown in class, the flow of audio processing in PureData is considerable natural, as it is in general pretty easy to translate the functional block diagrams seen during the lectures. Even though the simple examples seen in class are available for your reference, we encourage you to experience the creation of patches from scratch: we understand that trying to build basic effects in PureData is very convenient because it will allow you to both learn the basic principles behind the effect and get more insight on Pd and its already available (large) set of objects. A good set of Pd tutorials can be found here [1].

Another very intuitive programming language (being lower level) for signal processing is Faust [2], although it will be left out of support for these labs. Of course, you are very welcome to satisfy you curiosity. An excellent tutorial for audio signal processing in Faust written by Prof. Julius Smith can be found here [3].

Overview

Given that only dynamics-based effects have been covered in class, our first lab on making FX in Pd is based on those type of effects. The objective of this lab is to get familiarized with the effect design process, so that when further effect types get covered in class you can go ahead and try them yourself.

In this lab, we will build two effects from scratch: a tremolo effect, and a ring modulator (both with stereo output). For the more brave, we will guide you to the construction of a simple (mono) compressor.

In general, even though it is a good idea to first try the effects on your own computer (provided you have Pd installed) using audio files as input sources, we recommend to try your effects directly on CCRMA Satellite (first using a recorded sound source) when possible. If you are going to start trying out your effects first with a recorded sound and have not brought any sound file(s) with you, you can search and download (under a Creative Commons License) some clean guitar sounds from Freesound [4].

Effect 1: Tremolo

A first step is to have a clear idea of the overall operational structure of the effect. The actual realization and/or parameter tuning can of course vary depending on your preferences. For the case of a tremolo, the structure is pretty simple. We have seen that a tremolo effect is based on rapidly varying the amplitude of the input signal.

Changing the amplitude can be easily achieved by multiplying the signal by a number. This can be dong by so is the mull~ block:

Mul1.JPG


The idea is to generate an automatically changing