Generating a Signal from Waterfall

This section shows how to generate a signal from a Waterfall file, which includes a series of successive spectra associated to several RPM calculation points.

Note: The processing used in Sound: Analysis and Specification assumes that for each RPM point, the frequency lines are the same (for all RPM points: same number of frequencies, and same order of frequencies). Then, Sound: Analysis and Specification generates sinusoidal components whose frequency and level evolve according to the RPM. A linear interpolation of the dB level value is made to create the data between the known RPM points.

Sound creation is made using a linear RPM profile, in an RPM range specified by the user.

To use any RPM evolution (not neccessarily a linear one) you can define a harmonics source in the Sound Composer application (see Creating a Track with a Harmonics Source).

To Create a Sound from Waterfall Calculation:

Prerequisites: You need a waterfall from one of the supported types.
  1. Click File > Generate signal from Waterfall... and select a *.xml file containing a Waterfall spectrum.

    The Signal generation from spectrum window is displayed.

  2. In the Signal generation from spectrum window, type a Duration in seconds.
  3. Enter the Start RPM value.
  4. Enter the End RPM value.
    Note: You can choose Start and End RPM among the points defined in the XML file (click button ), or set them manually (you can chose any start and end RPM value, provided start is smaller than end).
  5. Enter a Sampling frequency in Hertz.
  6. From the Method list, choose Harmonic model to use a sinusoidal interpolation and create an harmonic sound
    Note: The only method supported for waterfall data is Harmonic model.
    Note: The RPM profile used for the sound creation is associated with the sound. For more information Associating a RPM Profile with a Signal, Displaying a RPM Profile, Order Analysis.
  7. Click Generate.
  8. Go to File > Save to create a WAV file.

The sound is created in a temporal window.

Tip: Next is right-clicking the waveform to calculate the spectrum.