Load a sweep recording (a rev-up or rev-down), then press Analyze Sweep.

01Analyze

Tracks: the harmonic lines found in the spectrogram. Click one to lock the contour to it. Shift/Ctrl-click a second piece of the same harmonic to join them. The gap between the pieces, such as a stutter in the sweep, is bridged and left out of slices.
Draw: click waypoints, then Apply Drawn to use them as the contour.

02Engine

RPM = fundamental × this multiplier. Set automatically from cylinders × strokes.

03Targets

No targets yet. Press Auto-Pick, or click the curve to add one.

04Slice

05Refine

Resynthesis measures the engine at each target RPM and rebuilds the loop from that: the engine's tone locked exactly to the RPM, plus fresh noise that never repeats. Nothing is spliced, so there are no joins to glitch and the loop wraps seamlessly at any length. Granular splices recorded cycles instead.
Start End
No sample selected. Import audio to get started.

Loop Seam Preview

Δ (sample-match)—
End − Start ZC—
Spectral Δ—

Loop Region

Start—
End—
Length—
Length (cycles)—
Estimated RPM—
Use + Import stable loops in the Samples panel on the left to build a blend bank.

Stable Loop Bank

Ready-made steady-RPM loops that need no editing. Import them from the Samples panel on the left and set each one's RPM. The blend data, meaning the RPM range and the pitch step to its neighbors, is worked out for the Simulator and Wwise. This is separate from the sweep workflow.

01Set RPMs

Auto-detect only gives a rough first guess. Correct each one with the spectrogram picker below, or the ÷2 and ×2 buttons on its row.

02Spectrogram

Click a loop row to open its spectrogram, then click the firing fundamental to set its RPM.

03Engine

RPM = picked fundamental × this multiplier (= 30 × strokes ÷ cylinders).

04Sort & test

Sort once all RPMs are set, then open the Engine Simulator to audition the blend.

Combo Engine

Pick from Available loops on the left. Click + or drag a chip into the green area to build a multi-RPM engine. Taking a loop out of the combo does not delete it from your project.

Available loops your sample pool

Your combo engine drop pieces here · low → high RPM

RPM Crossfade Curve

1000RPM

Volume curve

Linear interpolation between idle and redline. Use after normalizing loops to add the natural RPM loudness curve.

Samples in mix

Only the highlighted pool plays. Uncheck within it to A/B, or “solo” one loop.

FMOD export is not available yet.

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Ready.