Tape Hiss: Remove with Denoise

You digitized a cassette — and in every pause you hear soft sand on top of the music. That is tape hiss: not “mandatory tape character,” but a broadband floor you can ease without sterilizing the transfer. Here is how spectral denoise works, how it differs from de-hum/de-click, and how to clean a tape online.

Hiss, hum, and clicks are different problems

Analog transfers often mix three issues:

1. Tape hiss — constant broadband noise up top. Loudest in silence; soft notes “sand” a little.
2. Hum — a thin 50/60 Hz mains line and harmonics. Sounds like a low “bzz.”
3. Clicks / crackle — short impulses (dust, scratch, bad contact). Spikes, not a steady floor.

Denoise targets 1. Hum belongs to de-hum; impulses to de-click. A product walkthrough of the modules is on the audio restoration landing page.

How spectral denoise works in plain language

Spectral denoise estimates a noise profile (or uses a preset like tape hiss) and gently pulls down bins that look like that floor, more in quiet frames than in loud musical ones. That is why pauses clean up first, and why max strength starts chewing air and cymbals.

What denoise does not do:

• it does not notch a thin mains line — that is de-hum;
• it does not repair short impulses — that is de-click;
• it does not rebuild clipped peaks — see the declipper;
• it should not polish the whole track into digital silence — a watery artifact is worse than a soft hiss.

A cassette cleanup order that works

1. Transfer with headroom. WAV/FLAC, no input clip. Capture quality beats any plugin.
2. Rumble / high-pass. Cut deck/turntable infrasound (often around 30–40 Hz) so the limiter is not fed floor thump.
3. De-hum. If you hear constant mains buzz, notch it before broadband cleanup.
4. Soft tape-hiss denoise. Light → medium. Goal: quieter pauses, not a void. Prefer a tape_hiss-style profile over a hard top-end shelf.
5. De-click only if impulses remain.
6. Mastering. Platform LUFS/True Peak comes after the noise floor is even.

In Magic Master that chain is bundled as the Restore old recording intent: open in the app.

How to verify air and transients still live

• Pauses between phrases. Hiss should drop; no knife-cut silence or “underwater” pumping.
• Hi-hat and cymbals. Attack and shimmer stay; chewed hats mean denoise is too strong.
• Vocals and breath. Consonants stay natural; plastic “S” and missing air are over-clean tells.
• Level-matched A/B. The brain hears a quieter file as “cleaner” — compare honestly.
• Spectrum. The broadband top eases a little; you should not see a comb across the whole band.

If after cleanup the track is still a dynamics brick, that is over-compression, not tape hiss — see dynamics restoration.

Common mistakes

• Maxing denoise “just in case” — kills air and percussion.
• Killing hiss with one low-pass — you lose the tape’s top and the vocal presence.
• Mastering before denoise — the limiter stamps noise into loud moments, and aggressive cleanup then hurts the music more.
• Treating hiss like hum — a wide bass cut or a single notch will not fix broadband sand.
• Keeping “all the noise for vibe” when pauses mask soft notes — keep character with light denoise; remove impulses surgically with de-click.

In short

• Tape hiss is broadband top-end noise; denoise eases it, de-hum/de-click do not.
• Order: rumble → de-hum → soft denoise → de-click → mastering.
• Listen to pauses and cymbals; conservative strength is safer.
• Online without a DAW: audio restoration and the Restore old recording intent.
• Sibling articles: de-hum and cassette restoration, vinyl clicks / de-click.

Your first basic master per day is free; PRO restoration modules use the same token model.