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Workflow · Spectral repair

Take the cough out. Leave the chord.

A take is otherwise good except for one moment: a cough, a click, a chair squeak, a bite of hum. Re-recording isn't always possible: a client session that's over, a location interview, an archival recording with nothing left to re-record from. The specialized tools built for this exact job, select the blemish on a spectrogram and fix just that, are usually sold as a separate purchase or a subscription. Spectral mode does the same job inside the analyzer you already open to check the numbers.

macOS Spectral repair Attenuate / Erase / Repair Lasso · Brush · Wand One-time purchase No subscription 7-day trial
Read the spectral mode guide All of Specula

7-day trial · one-time purchase · macOS 14+

Specula's Spectral mode with a stereo file in the stacked Both view: a lasso selection drawn around a blemish in one channel's spectrogram, under the time ruler and waveform strip, with a frequency scale on the right and the violet spectral toolbar showing the four selection tools.
Spectral mode. Select the blemish on the spectrogram, then attenuate, erase, or repair just that.

When there's no take two

Everything about the take is right, except one moment.

You're most of the way through a review and there it is: a cough landing under a line of dialogue, a chair creak between two piano chords, a burst of mains hum riding under a quiet passage. Everything else about the take is right. Re-recording it means getting the room, the performer, and the take back, and sometimes that's not available at all: the client has left, the location shoot wrapped, the interview subject isn't coming back, the source is an archival transfer with nothing left to record.

The fix that specific problem needs is narrow: find the blemish in time and frequency, select exactly that, and process only the selection, leaving everything around it untouched. That's a different job from a general noise-reduction pass or an EQ move across the whole file, and it's usually priced and packaged as its own thing.

What that job costs elsewhere

Roughly $90 to $1,200 one time, or a subscription you keep paying.

Select-it-and-fix-it spectral repair is normally a specialist purchase: an entry-level spectral editor around $90, capped in sample rate and channels; a full spectral editor, or the restoration-suite tier that includes the select-and-fix tools, in the mid hundreds; the top suite tier, past a thousand dollars; or an editor on a subscription.

Specula doesn't sell spectral repair as a separate tier. Spectral mode is part of the $99.99 one-time price that also includes everything else on this site: loudness, FFT, spectrogram, compare, edit, record, and the signal generator.

How it works

Select the blemish, pick an operation, audition before you commit. All of it on a zoomable, full-resolution spectrogram.

1 · Select the blemish
⌘5 (or the Spectral button in the transport bar) turns the main canvas into a full-resolution, zoomable spectrogram of the loaded file. Four tools share one selection: Rectangle (R) for a straight time/frequency box, Lasso (L) for a free shape, Brush (B) for painting over a curved trace like a bird chirp or a whistle, and Wand (W) for one click: click a spot and the selection grows across the connected region at a similar level, shaped by a dB tolerance and a time reach that re-tune the last stroke live, so one click grabs the local stretch of a hum line, not the whole file, and dragging sweeps the wand along a blemish. The brush and wand paint: strokes add to the selection, an Option-stroke removes. With the rectangle and lasso a plain drag starts a new selection, Shift adds to it, Option subtracts, and Esc clears it. For stereo files the canvas shows the left channel, the right, or both stacked, so a blemish living in only one side is easy to spot. Multichannel files edit channel by channel: pick a channel of the bed (L, C, LFE, Ls, and so on, following the file's layout), fix it, and the other channels stay untouched, sample for sample; the selection persists across channel switches, so a blemish that spans channels is the same region applied a few times.
2 · Choose the operation
Attenuate lowers (or raises) the selection by a chosen dB amount, default −18. Erase (Delete) pushes it down to the noise floor learned from the audio just before and after it, minus an adjustable erase depth (default 12 dB), so removal stays decisive even inside busy material. Repair bridges it in time, interpolating each frequency's level from the clean audio on both sides, the move for a short blemish crossing otherwise steady material. Every operation feathers its edges in time and frequency, and applies to all channels by default or just the one you pick, since editing a single side of a stereo file can skew the image. The analysis window (1024 to 8192) trades time detail against frequency detail; changing it clears the selection since the underlying grid changes with it.
3 · Audition, then commit
Space plays the selection's span. Solo (⇧Space) plays only the selection itself, with the same feathered edges the operation would use, so you hear exactly what an Erase or Attenuate would touch before you touch it. Result (⌥Space) plays the span with the selection removed, an audition of the outcome. Spectral edits share Edit mode's undo history (16 levels), the selection survives an apply and an undo so you can iterate, and Save As always writes a new file, the original on disk untouched. Selections longer than 10 minutes are refused; select a shorter range and apply in passes. Full detail in the Spectral mode guide.

Up close

A wand selection hugging a harmonic shape in the spectrogram, with the wand's dB tolerance and time reach sliders visible in the violet spectral toolbar.
The wand. One click selects the connected region at a similar level; the tolerance and reach sliders re-tune it live.
The spectral toolbar with the Attenuate popover open: a dB amount field at the default −18 dB, over an active selection on the spectrogram.
Attenuate. Lower (or raise) just the selection by a chosen dB amount.

FAQ

Is Spectral mode an automatic cleanup tool?
No. Spectral mode is manual spectral editing: you see the problem on the spectrogram, select it with a rectangle, lasso, brush, or wand, and apply one of three operations, Attenuate, Erase, or Repair. There's no automatic de-noise, de-hum, or de-reverb pass at this time. The fix lands exactly where you point it, and nothing else changes.
Do I need a subscription to use spectral repair?
No. Specula is a one-time purchase, and Spectral mode is part of the $99.99 price, not a separate add-on or a higher tier. There's no recurring fee to keep using it.
How does it compare to the dedicated spectral repair tools?
Same core job, select a region on a spectrogram and fix it, different scope and price. The dedicated tools bundle spectral repair with a wider set of restoration modules at a specialist price. Specula bundles Spectral mode with the rest of its analyzer, loudness, FFT, spectrogram, compare, edit, record, at $99.99, one time. Neither is a strict subset of the other; pick based on which set of tools the job actually needs.

Fix the moment, not the take

Spectral mode is for the blemish inside an otherwise good recording: select it on the spectrogram, in time and frequency, and process just that region. It shares Edit mode's undo history and always saves a new file, so the original stays exactly as it was.

Read the spectral mode guide → Back to Specula