SpectraNull

Spectral audio comparison for macOS

See the change.
Hear the change.

Compare two mixes in time and frequency. SpectraNull aligns them, reveals what was added or removed, and turns the difference back into audio.

Explore SpectraNull Coming to the Mac App Store
  • Local processing
  • No account
  • macOS 14+
SpectraNull comparing two audio tracks with Mid and Side spectrograms and a combined spectral difference view

01 / Difference

A null test you can see
and actually listen to.

Coral shows energy added in B. Cyan shows energy removed from A. The combined difference stays synchronized with both tracks from the first transient to the last tail.

Monitor

Hear the processed track

Listen to B at the same playhead position, without stopping or losing your selection.

Track B · M+S

Monitor controls beside the combined Added and Removed Mid/Side difference spectrogram
One timeline. Five monitor sources. Three channel perspectives.

02 / Mid + Side

The center and the edges
tell different stories.

Every track and every difference is split into Mid and Side before matching. Hear a vocal move without the room, or a widening change without the center.

Track A and Track B shown as separate Mid and Side time-frequency spectrograms
M

Mid

The shared center: vocals, bass, kick and everything equal in left and right.

S

Side

The stereo difference: width, ambience, panning and channel-specific processing.

03 / Workflow

  1. 1

    Load A and B

    Mixes, masters, exports, captures or codec tests.

  2. 2

    Match before subtracting

    Align timing, correct polarity and normalize level.

  3. 3

    Point, select, listen

    The spectrogram is the timeline. Click or drag directly in it.

  4. 4

    Switch without stopping

    A, B, Added, Removed and Common remain sample-synchronized.

SpectraNull difference spectrogram, monitor selection and transport controls sharing one synchronized timeline
Space plays or pauses. Return stops and returns to the beginning. Difference boost starts at 0 dB.

04 / Under the hood

Precision first.
Everything stays local.

Analysis
Accelerate FFT · 75% overlap · logarithmic frequency
Alignment
GCC-PHAT · spectral flux · RMS · zero crossings
Playback
Inverse FFT resynthesis · synchronized crossfades
Privacy
No uploads · no analytics · no network entitlement

SpectraNull for Mac

Find the change hiding
between two files.

Ask about the launch