Audio Watermark Listening Test

This survey will test your ability to detect a digital audio watermark embedded in music files.

Digital audio watermarks hide extra information in an audio signal, usually for copyright enforcement purposes. The watermarks are designed to be inaudible, but necessarily add some distortion to the original audio.

Training Phase

The information below is meant to familiarize you with the sound qualities of the watermark before taking the test. Take your time with this material before you begin answering questions.

The following sample demonstrates a greatly exaggerated version of the watermark applied to a noise signal. The watermark starts after 2 seconds.

Audio sample containing an exaggerated watermark.

This distortion is visualized in the figure below, showing discrete blocks of noise that fluctuate in intensity over time.

Spectrogram of digital audio watermark
A spectrogram of the watermark by itself. The distortion lies in the region from 1 to 3 kHz.

In the following example, sample A is the original, and sample B is watermarked. The distortion is most audible during the loudest portion of the watermarked sample (B). Focus your attention on the voices of the choir. Listen for the rapid fluttering distortion, similar in character to the exaggerated example above. Switch back to the original sample (A) and notice that the fluttering is absent.




Below, you will find 16 groups of audio samples. In each group, you are presented with two versions of the same music sample. One contains a digital watermark, and the other does not. Switch back and forth between the two audio samples using the control buttons. Listen closely and try to determine which sample in each group contains a watermark. For best results, use headphones and take the test in a quiet environment.

Your score will be reported after you submit your answers.

  1. Bored With Four - Powerless Together

  2. Debussy - Arabesque

    Copyright ©2006 Naxos Rights International, Ltd.

  3. Shakey Graves - Unlucky Skin

    Copyright ©2011 Shakey Graves

  4. Santana - Every Day I Have The Blues

    Copyright ©2000 Purple Pyramid

  5. Debussy - The Engulfed Cathedral

    Copyright ©2006 Naxos Rights International, Ltd.

  6. Shirley Bassey - Diamonds Are Forever

    Copyright ©1988 EMI Records Ltd.

  7. XXYYXX - Fields

    Copyright ©2012 XXYYXX, ©2012 Relief in Abstract Records

  8. Beethoven - Moonlight Sonata

    Copyright ©2005 Naxos Rights International Ltd.

  9. Builders - Synthetic Flight

    Copyright ©2013 Builders

  10. Electric Light Orchestra - 10538 Overture

    ℗1972, 2003 Sony BMG Music Entertainment

  11. Pink Floyd - The Great Gig In The Sky

    Copyright ©1973 Capitol Records, Inc.
    ℗1973 The Gramophone Company Limited
    All lyrics © Pink Floyd Music Publ. Ltd./Chappell Music Ltd.

  12. Lady Gaga - Just Dance

    Copyright ©℗2009 Interscope Records

  13. Drake - Take Care

    Copyright ©2011 Cash Money Records Inc.

  14. Nirvana - Smells Like Teen Spirit

    Copyright ©℗2011 Geffen Records

  15. Ravel - Daphnis et Chloe

    Copyright ©1992 EMI Records Ltd.

  16. Kettel - Jongebeer

    Copyright ©2013 Kettel

I am listening with:

My listening environment is: