SOP: Verify Audio with SynthID Fresh

Date: February 2026 | Estimated Time: 5-10 minutes

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Purpose

Verify whether an audio file was created or edited by a Google AI model by checking for embedded SynthID watermarks using the Gemini App.

Prerequisites Checklist

• [ ] Personal Google account or Google Workspace account
• [ ] Latest Gemini App (web or mobile)
• [ ] Signed in to your Google account
• [ ] Audio file under 100 MB
• [ ] Audio duration under 1 hour
• [ ] Daily quota not exceeded (3 hours of audio verification per day)

Process Flowchart

Procedure

Step 1: Prepare the Audio File

Before uploading, verify:

1. File size is under 100 MB
2. Duration is under 1 hour
3. Format is supported (MP3, WAV, and other common audio formats)

Audio Quotas

Your daily audio verification quota is 3 hours total. Each file you verify counts its full duration against this limit.

Step 2: Open the Gemini App

1. Navigate to gemini.google.com on your computer, or open the Gemini app on mobile
2. Ensure you are signed in

Step 3: Upload the Audio File

1. Click or tap the Add files button
2. Select Upload from device (or Google Drive)
3. Choose the audio file
4. Wait for the upload to complete

Step 4: Ask the Verification Question

Type a verification prompt:

• Was this audio created by AI?
• Check this audio for SynthID watermarks
• @synthid verify this audio
• Is this AI-generated speech?

Press Enter or tap Send.

Step 5: Interpret the Results

Result	Meaning	Next Steps
SynthID watermark detected	Audio was created/edited by Google AI	Verification complete
No SynthID watermark detected	Not created by Google AI	May be other AI-generated audio or authentic
Unclear	Cannot determine definitively	Try with original/higher quality file

Step 6: If Results Are Unclear

1. Upload the original file — If you uploaded a compressed version, try the original uncompressed file
2. Check for speech synthesis artifacts — Listen for unnatural cadence, robotic tone, or consistent breathing patterns
3. Spectral analysis — Use audio software (Audacity, Adobe Audition) to inspect the spectrogram for unusual patterns
4. Metadata inspection — Check audio file properties for recording device info or editing software traces

Best Practices

• Upload original audio files whenever possible — avoid re-encoding before verification
• MP3 and WAV are the most reliable formats for verification
• Track your daily quota — 3 hours of total audio, cumulative across all checks
• For podcasts or long recordings, trim to the specific segment you want to verify (under 1 hour)
• SynthID audio watermarks survive resampling and compression, but original files yield best results

Verification Checklist

• [ ] Audio file is under 100 MB
• [ ] Audio duration is under 1 hour
• [ ] Audio is in a supported format (MP3, WAV, etc.)
• [ ] Uploaded to Gemini App successfully
• [ ] Verification question asked
• [ ] Result reviewed and documented
• [ ] If unclear: attempted with higher quality source
• [ ] If unclear: alternative analysis methods applied
• [ ] Findings recorded