#SONIC VISUALISER SPECTROGRAM SERIES#

Processing a signal requires revisiting segments repeatedly, making changes to portions and studying results closely. Easy export and import of audio files using export layer and handy annotation add to the glitz. Panes are horizontally-scrollable areas that can be stacked one above the other, and a pane can have any number of layers in it. Sonic Visualiser is structured around panes and layers. A friendly and appealing user interface lets us customise everything from default frequency to background colour. We could also have plugins in Linux Audio Developer’s Simple Plugin API (LADSPA) or Disposable Soft Synth Interface (DSSI) formats to create effects like compression or to generate data using controlling parameters like sine-wave tone or white and pink noise.Ī measure tool helps us select the exact range of the signal we want to work with, or maybe observe repeatedly to detect something amiss. The general format for audio-analysis and feature-extraction plugins is Vamp, which takes in audio input and generates output compatible with display of Sonic Visualiser layers. Third-party plugins can be used with Sonic Visualiser to enhance understanding of the input signal. Plugins to generate new layers and create effects As Sonic Visualiser website puts it, “a slice is to a colour 3D plot as a spectrum is to a spectrogram.”

For an instantaneous display of y-axis values of a 3D plot, we can invoke a slice layer. The plot is not editable and appears only when a transform whose output is appropriate for grid display is applied, or when importing certain types of annotation data. There is also a colour 3D-plot option for signals that have groups of frequencies at different time instants, with each group having its own value. Often, harmonic notes lead to confusion in audio analysis, and to help with this, this tool offers a harmonic scale to pinpoint respective signal frequencies. A note layer that helps group points as notes, a region layer to apply a particular operation on just a section of the signal and a text-and-image layer are also present. Hann window is the default and should be appropriate for most purposes.įor perfect time analysis of the signal, we can add vertical lines corresponding to a given time instant, label instants, display points differently, connect these via lines/curves or even segment regions. We can set window size for a frequency-time balance, fix window overlap to decide the proportion of overlap and select window shape from a list of Hamming, Hann (also known as Hanning), Blackman, Blackman-Harris and Nuttall (cosine based windows), Gaussian, Parzen, triangular and un-windowed (rectangular) options.

#SONIC VISUALISER SPECTROGRAM SERIES#

To obtain the spectrum or spectrogram, a series of Fourier transforms have to be applied to the signals. A very useful colour-rotation feature for sudden transitions helps isolate areas with similar signal levels. We can even observe waveforms in different colours according to frequency. An online course explains a spectrogram thus, “Speech is a continuous flow: phones are not discrete or distinct from each other, but these merge into one another, and spectrograms assess and visualise this continuity.”īoth of these visualisations allow us to change the scale and range of the signal in display.

Brightness or colour of pixels indicates the phase changes. A spectrum can be considered a vertical slice of a spectrogram (a spectrogram describes the change in frequency over time).

Sonic visualiser spectrogram