Auditory Illusions Phy103 Physics of MusicJ. S. Bach's canon per tonusCanon circularis per tonos (Bach) A musical offeringDescending Pitch IllusionFalling bellsEndless rising pitchesOpening song from anime series GunXswordA Melody of SilencesReflection as a compositional themeNow with the musicNow with the spectrum?Can we pick out time reversal symmetry (tune followed by itself played in reverse order)?Reflection in time -- now with the music Axis of symmetry is a time Example from Larry Solomon) Anton Webern, Opus 27Earthquakes from somewhere in Ethiopia – Cindy EbingerOverlapping piano tonesMore on echo suppressionSensory Integration IllusionLady Gaga exploiting the McGurk Effect?Phantom or Combination tonesPhantom or combination tonesTiming and musicA Discontinuous Change in Time Perception Caused by Time-ShrinkingTime shrinkingQuickening BeatSlide 25Musicianship in timingGap Transfer illusionMore on Gap-Transfer IllusionSplit off effectMore on the split off effectMore on split off effectStreamingPhantom MelodiesFast rhythm even in presence of timbre variations can lead to hearing groups of sounds as single sounds “perceptual groupings”Slide 35Effects of Timbre on Auditory Stream segregationCharacter of song can remain despite large timbre changesRemake atrociousHacking a recording to change meterIllusory ContinuityTemporal Induction of SpeechPitch depends on partial frequenciesTimbre depends on frequencyStereo Auditory illusionsChromatic illusionDeutsch’s Tritone paradoxTritone paradoxZwicker ToneThings I might want to add to this lectureAuditory IllusionsPhy103 Physics of MusicJ. S. Bach's canon per tonusA very famous example of an endlessly rising melody is the canon per tonus from Johann Sebastian Bach's Musical Offering. The melody rises two half-tones each time the canon is repeated (this should illustrate the rising glory of Frederick the Great to whom the Musical Offering was dedicated). The canon starts in C minor. After the first run it ends in D minor, so the second turn begins two half-tones higher than the first one. When the canon is repeated further, it begins in: c1, d1, e1, f#1, g#1, bb1, c2, d2.Canon circularis per tonos (Bach)A musical offeringDescending Pitch Illusionhttp://asa.aip.org/demo27.htmltime frequency Falling bellsPitch is actually rising even though it sounds like it is falling From: http://listverse.com/2008/02/29/top-10-incredible-sound-illusions/interesting in stereo tootime frequency Endless rising pitches•Each tone contains separations 7/6 of an octave with an envelope that is fixed•Each tone is shifted by 100 cents or 1 semitone“Shepard tones”timefrequencyOpening song from anime series GunXswordtime frequency A Melody of Silenceshttp://www.kyushu-id.ac.jp/~ynhome/ENG/Demo/illusions.htmlc2000 Yoshitaka Nakajima timenotesReflection as a compositional theme•Bartok “Subject and Reflection”, Mikrokosmos, vol 6, #141 played by Jeno Jando•Can your ear pick out the reflective tonal symmetry without seeing the music?•Two melodies played one goes up while the other goes down and vice versaNow with the musicNow with the spectrum?•Is the reflective tonal symmetry obvious in the spectrum?•Compare how easy it is to SEE this pattern compared to how easy it is to HEAR this patterntimefrequuencyCan we pick out time reversal symmetry (tune followed by itself played in reverse order)?Without the music Anton Webern, Opus 27Reflection in time-- now with the musicAxis of symmetry is a timeExample from Larry Solomon)Anton Webern, Opus 27Earthquakes from somewhere in Ethiopia – Cindy Ebinger•Original file sampled to 50Hz•We multiplied by 400 to 20KHz•2 hours of data reduced to 18sreversedBOVENo time reversal symmetry in hearing due to echo suppressiontimefrequencyOverlapping piano tones•forward•backwardoverlaps aren’t heard in forward but are heard in backwardEcho suppressiontimefrequency waveformMore on echo suppression•http://www.youtube.com/watch?v=7At6BhGOQzo•He's a Pirate - IMPOSSIBLE REMIX•https://plus.google.com/u/0/wm/4/+BobGmbH3000/aboutSensory Integration IllusionWhat you see affects what you hearMcGurk effecthttp://www.youtube.com/watch?v=aFPtc8BVdJkMusic dubbing is very convincinghttp://www.youtube.com/watch?v=bESGLojNYSoLady Gaga exploiting the McGurk Effect?Phantom or Combination tonesoTwo tones are played, one at 1000 Hz, the other rises linearly from 1000 Hz to 1400 Hz.Listen for a third, downward moving toneThanks to Nate Zuk (though I am not sure where the demo file came from)frequencytime  1kHz-0Hz-2kHz-Phantom or combination tones•Non-linearity in the ear produce tones at sums and differences of multiples of frequencies•Two tones with frequencies f1, f2•You might hear f1+f2, f1-f2, or 2f1-f2time  1kHz-0Hz-2kHz-f2=At+1kHzf1=1kHz2f1--f2=1kHz-Atphantom toneTiming and musicScott Joplin’s The Peacherine•MIDI from http://www.geocities.com/BourbonStreet/2783/sjmidi.htm•Played by Dick HymanJoplin sounds pretty good in MIDI --- it was played on piano rollsA Discontinuous Change in Time Perception Caused by Time-Shrinking When the difference between the first and the second duration is up to about 100 ms (the sixth pattern), 'time-shrinking', i.e., the second duration is under-estimatedFigure and clip by Yoshitaka NakajimaTime shrinking Duration of short time intervals is conspicuously underestimated if they are preceded by shorter neighboring time intervals.Figure by Petra Wagner and Andreas WindmannQuickening BeatFrom: http://listverse.com/2008/02/29/top-10-incredible-sound-illusions/Tempo appears to be quickeningMusicianship in timingNote double hits by bass Percy JonesDifferences in timing of bass compared to drum make each instrument stand out yet rhythm is still strongGap Transfer illusion•A bounce is often perceived in the gliding tones•http://www.kyushu-id.ac.jp/~ynhome/ENG/Demo/2nd/01.htmlFigure and clip by Yoshitaka NakajimaMore on Gap-Transfer Illusion•Often perceived the sameFigure and clip by Yoshitaka NakajimaSplit off effect•The listener typically perceives one long tone, which rises and then falls, and a short tone in the middle. Figure and clip by Yoshitaka NakajimaMore on the split off effectFigure and clip by Yoshitaka NakajimaMore on split off effectFigure and clip by Yoshitaka NakajimaStreaming•When do two alternating pitches sound like one galloping sound? ASA demo 19 •Yodeling -