Voxengo SPAN

Master Your Tonal Balance: High-Resolution Frequency Analysis

A major pain point for producers is “mixing in the dark.” If your room isn’t acoustically treated, you may be boosting frequencies you don’t need or missing a massive buildup in the low-mids. SPAN solves this with a highly flexible “Mode” system. 

You can adjust the Fourier Block Size for ultra-fine resolution in the low end, or increase the Smoothing to see the general “contour” of your mix. 

By setting the Spectrum Slope to 4.5 dB (the industry standard), you get a visual representation that aligns perfectly with how the human ear perceives loudness across the frequency spectrum.

Solving the Stereo Mystery: Mid-Side and Correlation Metering

In 2026, a wide stereo image is vital, but phase cancellation can ruin a mix when played back in mono (like on a phone or club system). SPAN features an integrated Stereo Correlation Meter that alerts you to phase issues instantly. 

Furthermore, its advanced Mid-Side analysis allows you to visualize the center (Mid) and the sides of your mix separately. This is a game-changer for ensuring your lead vocals stay “anchored” while your atmospheric pads provide the width you need, without washing out the mix.

Workflow Enhancements & Interface Customization

Despite being free, SPAN includes workflow features typically reserved for premium analysis suites:

• Preset manager
• A/B comparison system
• Undo/redo history
• Contextual hint messages
• Resizable interface
• Multiple UI color schemes
• Retina and High DPI support

The interface can be scaled for detailed full-screen analysis or compact master bus monitoring. Color themes allow you to adapt the visual aesthetic to your session environment.

Internally, SPAN operates in 64-bit floating-point processing and supports all sample rates, ensuring precision and stability in modern production environments.

Real-Time FFT Analysis With Total Control

At its core, SPAN is a fast Fourier transform (FFT) analyzer, converting audio signals into a detailed frequency spectrum in real time. What sets it apart from simpler analyzers is the level of control it gives the user.

You can configure:

• FFT block size for precision vs responsiveness
• Window overlap percentage
• Spectrum slope (for flat perceptual display)
• Secondary spectrum displays (real-time max, all-time max)
• Visual smoothing for easier interpretation

This flexible mode system allows you to tailor SPAN for mastering precision, mix referencing, or problem-solving resonance detection.

For producers working across genres, this adaptability is crucial. Tight, transient-heavy material may benefit from smaller block sizes, while mastering engineers often prefer higher resolution FFT settings for forensic analysis.