Audio Watermark — Inaudible Copyright Signature

A free tool that hides ownership text — your name, channel URL, an order number, a client ID — inside any audio file using an ultrasonic spread-spectrum signal. The signature is inaudible on normal playback, survives MP3 re-encoding at 128 kbps and above, and can later be read back here to prove the file came from you. Useful for podcasters sending unreleased episodes to producers, beatmakers sending tagged demos to clients, voice-actors sending audition tracks, and anyone shipping audio to a third party before payment clears.

How to Use

Upload your audio file

Open the Embed tab and select an MP3, WAV, OGG, or FLAC file from your device.

Enter watermark text

Type your name, website URL, or any identifier you want to embed as proof of ownership.

Choose strength level

Select Light for delicate recordings, Normal for everyday use, or Strong for files that will undergo heavy compression.

Embed and optionally add metadata

Click Embed Watermark. Optionally check "Also embed in file metadata" for dual protection.

Download and verify

Save the watermarked file, then use the Detect tab to confirm the signature was embedded correctly.

Stamp your podcasts, beats and voice-overs with an inaudible copyright signature

Drop audio file here or click to browse

MP3, WAV, OGG, FLAC, AAC, M4A, M4B, WMA, AIFF, OPUS, CAF ·

Watermark Text

Strength

Also embed in file metadata Adds watermark text to audio metadata as secondary protection

Output Format

Lossless format — watermark fully preserved

Original

Watermarked

Designed to be inaudible on standard playback

Download Watermarked Audio

Drop audio file here or click to browse

MP3, WAV, OGG, FLAC, AAC, M4A, M4B, WMA, AIFF, OPUS, CAF ·

Features

Spread-spectrum steganography at 18.5 kHz carrier — below the threshold of perception Four strength levels: Transparent (inaudible for pro mixes), Light (minimal impact), Normal (recommended), Strong (maximum durability) Optional metadata embedding stores watermark text in file tags as a second layer of protection Built-in detector verifies and reads hidden signatures from any uploaded audio file

FAQ

Can people hear the watermark?

No. The watermark is encoded at an 18.5 kHz ultrasonic carrier using spread-spectrum modulation. At Normal strength it is completely imperceptible on any standard playback system.

Does it survive MP3 compression?

Yes at Normal and Strong settings. MP3 encoding removes some high-frequency energy, but the spread-spectrum signal is distributed broadly enough to survive typical 128–320 kbps compression. Light watermarks may weaken after aggressive compression.

What languages and scripts are supported?

Any text encoded as Unicode UTF-8 works: Latin, Cyrillic, Arabic, Chinese, Japanese, Korean, and all other scripts. Emoji are supported too.

What is metadata embedding?

Checking "Also embed in file metadata" writes the watermark text into the audio file's ID3 or Vorbis comment tags. This provides a second, easily readable layer of ownership information alongside the hidden steganographic signature.

Can I use the watermark to prove ownership in court?

A steganographic watermark can serve as supporting evidence of authorship — especially when combined with metadata embedding and a dated original file. However, it is not a legal certificate by itself. For formal copyright registration consult the relevant authority in your country.

💡 Want us to improve this tool just for you?

We can — and it's free! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.

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3.7 (3 ratings)

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Published 07 Mar 2026 Updated 10 Jun 2026