Voxengo SPAN Plus

SPAN is a free audio spectrum analyzer that was derived from the Voxengo dynamic parametric equalizer. SPAN Plus-is a modification of SPAN. The main features of SPAN Plus are:

  • - Smoothing of the spectrum,
  • - Resizing the interface,
  • - Import and export of spectrum in real time,
  • - Export of PNG files,
  • - Display of static spectra,
  • - K-metering,
  • - Correlator,
  • - Analysis of multiple stereo channels,
  • - Mid/side analysis,
  • - Grouping of channels,
  • - Internal channel routing,
  • - Support for all sample rates,
  • - Contextual help.

SPAN Plus is a flexible system that can be used to configure the necessary parameters of the spectrum analyzer. It is possible to specify:

  • - Size of the Fourier block in samples,
  • - Visual slope of the spectrum,
  • - Percentage of overlap of the FFP window.

Additionally, you can choose to display the desired type of secondary spectrum. At the same time, it can be visually smoothed to simplify the study.

In addition to cross-spectral comparison, it also supports multi-channel analysis and can be used to display the spectrum of multiple channel groups simultaneously. The color of the displayed spectrum can be selected individually based on personal preferences. Correlation measurement is also available. SPAN Plus measures K-systems, output level with adjustable ballistics, and EBU R128.

The plugin is implemented in the form of multiplatform C++ code and uses the “zlib " compression library. It can be installed in any host application that meets the AudioUnit, AAX or VST plug-in specifications.


  • - Windows (Windows XP, as well as newer versions, unless specified as unsupported),
  • - MacOS (from 10.11, as well as newer versions if not specified as unsupported).

To work correctly, the necessary computer characteristics must match the parameters:

  • - Processor power of at least 2.5 GHz,
  • - At least 4 GB of RAM.

If SPAN Plus does not work correctly on the MacOS operating system, you must restart your computer. This error is not related to the plugin’s incorrect operation.