How to use Fugue State

Install & open. Download the app for your platform from the downloads page and launch it. The first window lists your projects; create a new one to begin. Your projects and audio stay entirely on your machine.

Import audio. Drag an audio file onto the window (or use the file picker). Fugue State analyzes it — computing the FFT, constant-Q transform, and onset data — and caches the result, so re-opening a project is instant. Most common formats work (MP3, WAV, FLAC, and more).

Prefer not to install? The in-browser demos run the same engine on pre-analyzed tracks — a quick way to see what the displays do.

The workspace is a grid of resizable panes. Right-click a pane to split it, change its view, pick a channel (left, right, or both), or close it — so you can watch several representations of the same moment at once.

• Spectrogram — energy across frequency (vertical, perceptually/mel-scaled) over time (horizontal). Bright = loud. The playhead stays centered as audio scrolls past.
• Constant-Q transform (CQT) — like the spectrogram but with a log-frequency axis aligned to musical pitch, so octaves are evenly spaced and notes line up. Best for hearing harmony and melody.
• Spectrum (Fourier) — the live frequency spectrum of the moment currently playing, updating in real time.
• Waveform & timeline — the amplitude envelope and a zoomed-out overview for scrubbing across the whole track.

Every time-based display shares the same gestures:

• Zoom time — scroll the mouse wheel over a display to zoom the time axis in and out.
• Scrub — left-drag across a display to move the playhead; playback pauses while you drag and resumes when you release.
• Frequency minimap — the strip on the right edge controls which frequency band is shown. Drag its top or bottom edge to widen or narrow the range, drag the middle to pan up/down, and click outside the selection to recenter. The change is shared across panes, so they stay locked together.
• Hover — a cursor line shows the exact frequency and nearest musical note under the pointer, mirrored across panes.

The transport bar at the bottom drives playback:

• Play / pause with the transport button.
• Speed — slow a passage down to study it. Pitch is preserved, so it stays in tune at any speed.
• Loop — set a loop region to repeat a tricky bar over and over. Loop handles appear on the timeline.
• Volume — adjust output level without affecting the analysis.

Open the audio-controls panel for finer control over what you hear. The visual displays follow these changes so the coloring always matches the sound:

• Tuning — pitch-shift up or down by up to an octave (±1200 cents, in semitone steps) without changing speed, via a real-time phase vocoder. The spectrogram/CQT shift their frequency axis to match.
• Channel mode — listen to Stereo, Left only, Right only, Mid (L+R), or Side (L−R) to isolate what sits in the center vs. the sides of a mix.
• 10-band EQ — boost or cut bands from 32 Hz to 16 kHz (±10 dB) to emphasize an instrument or tame a frequency.

Practice mode lets you play or sing along with the track and capture takes to compare against it. Toggle it with the microphone button in the toolbar. The view splits into the reference spectrogram (top) and your take (bottom), aligned to the same timeline so you can see exactly where you land.

• Arm & record — the record dot in the take selector arms the mic; press play and it captures a new take. Selecting the “new take” slot auto-arms; loading a past take switches to playback.
• Punch in — select an existing take, arm, and play to re-record over it from the playhead, keeping the rest.
• Loop & stack — while looping, each pass finalizes a take and rolls over to a fresh one, so you build up attempts bar by bar.
• Compare — play a take back alongside the song. Takes stay in tune and in time even when you change speed or tuning, so the comparison is always fair. Pitch detection overlays show how close your notes are.

Takes live in the current session — export or keep what you need before closing the project.

Fugue State can separate a track into stems and add a “vocals removed” source. Switch a pane (or the global track) to it to study or play along with the instrumental, or compare the isolated parts against the full mix. Separation runs locally and may take a little time on first use.

• Slow a fast run to half speed and zoom the time axis to read individual notes.
• Switch a pane to CQT when you care about pitch/harmony; the spectrogram when you care about timbre and noise.
• Narrow the frequency minimap to a single instrument’s range to see it clearly.
• Use Mid/Side mode to pull a centered vocal forward or push it back.
• Loop a hard bar, drop the speed, then bring it back up as it gets comfortable.