Disclosure: This page may contain affiliate links. Prices were checked on the date shown and may change.
An introduction to Voxengo SPAN, based on information from the maker and distributors: what it does, how to use it and who it may suit. It is not scored.
SPAN is a free real-time 'fast Fourier transform' (FFT) audio frequency spectrum analyzer AAX, AudioUnit, and VST plugin for professional audio and music production applications.
— Voxengo official site
What is SPAN?
SPAN is a free spectrum analyzer plugin from Voxengo. It splits sound into frequencies and graphs, in real time, how loud each band is.
The maker describes it as an FFT (fast Fourier transform) analyzer for professional audio and music production. It comes in VST, VST3, AU and AAX formats for 64-bit Windows and Mac hosts.
Besides the spectrum display, it bundles level meters, EBU R128 and K-system meters, RMS and true peak measurement, clipping detection and a stereo correlation meter.
It supports stereo, mono and mid-side display as well as 7.1 and 5.1 surround. Two channels or channel groups can be shown at once, so you can compare two sources.
Voxengo presents SPAN as a real-time FFT spectrum analyzer, developed by Aleksey Vaneev and distributed free of charge.
The list of supported hosts is broad: besides DAWs it names OBS, WaveLab, Adobe Audition, Vegas, Sound Forge, GarageBand, Cakewalk, Samplitude, Digital Performer, Mixcraft and Edius, covering recording, editing and video tools.
FFT spectrum analyzer
Analyses sound by frequency and graphs which bands are strong or weak, helping you check low-end build-up or lack of highs visually.
Stereo, mono and mid-side display
Switch between viewing left/right together, mono, or mid and side separately, useful for checking stereo width.
Surround support
7.1 and 5.1 surround spectra can be shown, which suits audio work for video.
Mode system
A mode system sets FFT block size, window overlap and the spectrum's visual slope, letting you tune detail and readability.
Metering
EBU R128 and K-system metering (with calibration), RMS and true peak, headroom estimation, clipping detection and a stereo correlation meter.
Two spectra at once
Shows the spectrum of two channels or groups at once, handy for comparing two tracks or before and after.
Display aids
A secondary display such as real-time or all-time maximum, visual smoothing and adjustable spectrum colour.
EBU R128 and K-system metering
Level metering covers EBU R128 and K-system, including K-system calibration, along with RMS, true peak level and clipping detection.
Adjustable ballistics and statistics
Meter ballistics and integration time are adjustable, and level statistics and headroom estimation are provided.
Stereo correlation meter
A stereo correlation meter shows the relationship between the left and right channels, which helps when checking for phase problems.
Several color variants
Blue, gray, beige, black, navy and more are available, so you can choose a display that suits your working environment.
Specifications
| Item | Details |
|---|---|
| Price | Free |
| Formats | Windows: VST / VST3 / AAX; Mac: AU / VST3 / AAX |
| Platforms | 64-bit macOS / Windows |
| Hosts | Ableton Live, Cubase, Logic Pro, REAPER, Pro Tools, FL Studio, Studio One, Bitwig Studio, Nuendo, WaveLab and others |
| Version | 3.24 (from download file names; not stated on the page) |
| User guide | PDF in English, French, German and Russian |
| Channels | Multi-channel analysis; two channels or groups shown at once |
| Surround | 5.1 and 7.1 spectrum analysis |
| Metering | EBU R128, K-system, RMS, true peak, stereo correlation |
| Color variants | Blue, gray, beige, black, navy and more |
What is included and system requirements
- The plugin itself (free)
- macOS installer (.dmg: AU / AAX / VST3)
- Windows installer (.exe: VST / VST3 / AAX)
- User guide and primary user guide (PDF)
- Installation guide
How to use it
- Download the installer for your OS from the official Voxengo page.
- Run it and choose the plugin format you need, such as VST3.
- Restart your DAW and rescan plugins.
- Insert SPAN at the end of the chain on a track or the master bus you want to inspect.
- Switch between stereo, mono and mid-side display.
- Use the mode settings to adjust FFT block size and slope.
- Check the meters (RMS, peak, correlation and so on) alongside the spectrum.
Checking mix balance
It may help you check low-end build-up or overly strong bands with your eyes as well as your ears.
Pre-mastering checks
True peak and EBU R128 meters may help you check levels before export.
Comparing two sources
The two-channel display may help compare the frequency profile of a reference and your mix.
Checking stereo width
Mid-side display and the correlation meter may help you see how a mix behaves in mono.
Checking frequency balance of a mix
Placed at the end of the master or a group bus, it may help you see how the low and high ranges are behaving.
Checking loudness for streaming or mastering
Since it offers EBU R128 metering, it may also be useful when you want to check loudness for delivery.
Who it may suit
- People looking for a free spectrum analyzer
- Home recordists who want to check mix balance visually
- Users who want loudness and peak meters in one plugin
- Those working with surround audio
Good to know before you buy
- It is a display tool and does not change the audio.
- Available formats differ by OS (Windows: VST/VST3/AAX; Mac: AU/VST3/AAX).
- User guides are PDFs in English, French, German and Russian.
Price
Free to use (Voxengo official site, checked 2026-10-27).
Sources: voxengo.com (checked 2026-10-27)
Comments