Bach: an illusion of two violins

There is a concept in auditory scene analysis (how we separate and group all the sound sources we might hear at once, like the cocktail party effect) called “auditory streaming”. It just means that we will tend to group sounds of similar pitch into the same perceived object. For example, I could play you a trill on a piano (so, two notes not separated much in pitch), and you would hear it all as one stream. If instead I played two notes separated much more in pitch, you would interpret that as two different streams.

Bach uses this idea in his Prelude for Partita Number 3 for solo violin, to create the illusion of multiple violins. Below is a video of Jascha Heifetz playing the Prelude ( There are many points during the piece when the violinist bounces back and forth between low and high pitches so quickly that it sounds like two violins are playing. Best places in the video to hear this: 2:30-2:43, 2:59-3:03, and 2:08-2:13.

May 15, 2007. music, sound. 3 Comments.


  1. ibar replied:

    wow, the video is really cool! i’m honestly not sure what inspired me to flag it 600 times as “inappropriate” on YouTube.

    May 16th, 2007 at 1:23 am. Permalink.

  2. Jasker replied:

    That isn’t really apparent to me as two violins, but that may possibly be because I’m a violist.

    October 5th, 2007 at 10:52 am. Permalink.

  3. Dietrich Lasa replied:

    Bravo, unbeatable performance. I am not sure if Bach thought of two violins or not. It is an interesting question – but perhaps when we listen to the beauty of this music, all questions subside spontaneously; at least that’s what I like most when listening to music – questions just disappear, and therefore answers are not looked for. For once we live in the present Now and enjoy the music as long as it lasts, and then we enjoy the silent after-effect as well as if it was part of the music.

    February 26th, 2009 at 8:22 am. Permalink.

Leave a Reply

Trackback URI