Sound Explorer

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Sound Explorer

Idea / Premise

Sound Explorer is an environment for exploring and shaping sounds in real time.


During my studies at CCRMA I'm exposed to many new audio / DSP concepts. Sometimes, however, it's hard to get a good intuition as to how things sound. I would like to have a tool that allows me to shape waveforms in various ways and hear the results. From my experience using sndpeek and assignment 3, there's a strong motivation to make the tool real-time since that helps make the correlation between the manipulation and the resulting sound most obvious.

Product Description

Sound Explorer allows the user to interactively construct and shape sets of waveforms. The results are displayed using a waterfall plot and the audio played back in real time. The ways in which the waveform can be shaped are:

  • Frequency domain:
  • Generate a harmonic series starting at a given frequency
  • Control the amount of non-harmonicity (i.e. how much the partials deviate from multiples of the the base frequency).
  • Generate white noise
  • Draw a spectral envelope
  • Time domain:
  • Draw a time-domain envelope

In addition, for most of the above shaping methods, there will be a way to control which part of the waveform to apply them to. For example, it will be possible to apply a time-domain envelope to a subset frequencies.


* Interface:

The interface is made out of three elements: graphical display, keyboard input, and mouse input.
  • Graphical display
The screen is divided into three parts:
  • Waterfall display: a waterfall plot of the audio currently being played
  • Edit window: this is where the user manipulates the waveform. At any time, this window is either in "additive mode" or "envelope mode". Each of those modes be in the frequency or time domain.
  • Apply-to window: in this window, the user highlights which portion of the audio to apply the edit to. The window can be in the time or frequency domain.
  • Mouse input: is used to draw envelopes and select ranges (in the apply-to window).
  • Keyboard input: used to control modes and various parameters.

* Software

  • The program will use OpenGL for graphics, RtAudio for audio, and FFT routines from the Chuck.
  • I will attempt to construct the program using the model / view / controller design patten. The model, for example, contains the samples for the current (and next) set of waveforms, the current envelope values, and the range and domain(s) to which the envelope(s) is applied.
  • Real Time interaction
    • The end goal is to have the user's interactions reflected in audio and graphics immediately. Initially, however, there may be two steps involved: 1) edit the wave:form 2) apply the changes and hear/see them.


The software will be tested by letting a user try it out and evaluate the:

  • flexibility / expressiveness
  • usability
  • sound quality
  • can interesting sounds be created?


Roy Fejgin


  • 11/16/09:
  • Waterfall window; "Time domain edit" window; audio rendering.
  • 11/23/09:
  • Apply-to window
  • 12/07/09:
  • Frequency domain processing:
  • "Frequency-domain edit" window
  • More sophisticated DSP: overlap add
  • Add harmonic series