sonogram sg-1 

A scrolling sonogram for frequency analysis.


details

Click to view full-size... Figure 1
Analysis of a Moog Voyager saw wave through a sweeping resonant LPF, with SG-1.
Clicking on the analysis window highlights Hz and dB values on the rulers.

SG-1 gathers some features which are usually isolated in other sonogram tools.
It works in real-time. It continues analyzing in the background, and only stops when you freeze it. Both in frozen or running mode, every time you click or drag within the sonogram area, frequency and amplitude rulers highlight the values corresponding to that point.
A little LED-like screen shows you in detail analysis information and parameter modifications, or the transport position when idle.


Click to view full-size... Figure 2
With a different palette, we can highlight minimal noises and filter sweeps at the beginning of Depeche Mode's song:
"Only when I loose myself".

The unusual thing: it comes with six scientific color palettes (twelve considering they can be inverted, by clicking the palette twice), which can be switched on the fly with a single click. Each of them can highlight different dynamic ranges, from high power kickdrum beats, to little spikes coming out from the noise floor.
Every palette can be shifted by simply dragging the dB ruler, to better contrast the right amplitude ranges.

Click to view full-size... Figure 3
Here's the zoomed trace of the legendary whistle from Ennio Morricone's soundtrack score: "Per qualche dollaro in pił".

You can vary the number of snapshots-per-second on the fly, to increase or decrease the time resolution. At any time you can change the zoom ratio, without loosing in resolution over the signals which have already passed by.
Of course you can scroll the zoomed screen while analyzing, to easily locate the frequency range of interest.
A mark button is provided: it allows highlighting interesting parts of the waveform for subsequent individuation.



technical notes

  • Every editable parameter supports host automation
  • GUI resources are just loaded once, no matter how many instances you run in your host.

This first version has some hard-coded properties:

FFT Size 8192
FFT Window Function Blackmann
FFT Window Overlap 50%
Minimum spectrum power -96dB
Amplitude scale logarithmic
Frequency scale linear
Input signal stereo merge


Remarks:

  • Since this analysis plugin leaves unaltered the output signal, the process function copies the inputs to the outputs and imediatley returns: every calculation is made in a separate thread, to give priority to the other effects in the chain. Consequently, the CPU load shown by your host could be inferior to that taken up by the SG-1, especially at high snapshots-per-second values.
  • I suggest to set your audio card's latency to values lower than 5ms, because high latencies will limit the smoothness of SG-1. In particular, you won't be able to use fast snapshots-per-second settings.


download

Last updates:
  • [14/10/2005] Fixed frequency display
  • [14/10/2005] CPU blended version released
  • [28/09/2005] Fixed a little bug which crashed some versions of Wavelab

Before downloading, please read the license agreement carefully.

Win32  VST Sonogram SG-1 v1.0 (Win32 VST)