#albertsbregman

[illusionsongs]

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This one demands headphones! Here's yet another variation of the same Amadinda xylophone music I've posted previously, except that it's now panned so that the physical distance between the parts is increased, causing a new perception of the melody and rhythm. Researcher Albert S. Bregman explains: "the piece starts with the two parts interleaved and playing to both ears. Then the first part moves to the left ear, and the second to the right, leading to the separate perception of the two parts with their own isochronous rhythms and the loss of the high and low emergent parts with their irregular rhythms."

This highlights a really interesting part of sound perception: the way that our ears perceive and process information individually in isolation (like when you're wearing headphones) can be different than how they perform together in the open air. In this case the headphones and hard panning to left and right creates the functional sensation of two sound sources with very different locations. How well can you hear the effect without headphones?

[illusionsongs]

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In this next version of the same Amadinda xylophone song I've been posting about, the way that we perceive the melody is drastically altered by the placement of each part in a different pitch range. According to Bregman "the lower part begins alone. Then it is joined by the higher part.  Because the two are an octave apart, their individual isochronous rhythms continue to be heard, and the emergent high and low irregular rhythms are lost."  Because the distance between parts is sufficient for us to separate them out into two different streams, they remain distinct and rhythmically uniform, never merging to create a more complex combined rhythm.  You can hear the original example of how we can perceptually merge the parts into one stream to make a new rhythmic pattern here.

Copyright Albert S. Bregman.

[illusionsongs]

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In this version of the same Amadinda xylophone music I posted previously, the timbre of one part is altered.  According to Bregman, "the timbre difference between the two individual isochronous parts allows them to be heard individually, and the emergent irregular melodies to be lost".  In other words, timbre is one of the factors that allows us to separate sound sources from each other.  In this case, the different timbres help us keep track of both parts at once.

Copyright Albert S. Bregman.

[illusionsongs]

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This piece of Amadinda xylophone music is a perfect example of auditory streaming, and our inability to pay attention to more than one stream at a time.  Albert S. Bregman explains: "first we hear one player's part, then it is joined by the second part, causing the melody and isochronous rhythm of the first part to be lost perceptually. Then the second part is played alone. Finally when both are played together, the melody and isochronous rhythm of the second part are lost."

Copyright Albert S. Bregman.