Playing the Audience Like a Xylophone

By Sean Carroll | July 28, 2009 10:19 am

This was originally relegated to a tweet, but it deserves to be elevated to a blog post. Bobby McFerrin, at the World Science Festival, demonstrating the pentatonic scale. A rare combination of joy, passion, and teaching. I dare you not to smile at the 0:42 mark.

World Science Festival 2009: Bobby McFerrin Demonstrates the Power of the Pentatonic Scale from World Science Festival on Vimeo.

  • Analyzer

    Joy and passion, sure. I enjoyed the video, and I wasn’t even in the audience. But what am I supposed to have learned from it? “Humans have ears for music”? I don’t get it.

  • Pieter Kok

    When he says it works on any audience, I am wondering if he has tried this in China.

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  • Egaeus

    @Pieter Kok

    Traditional East Asian music is based on the pentatonic scale. It’s more surprising to me that it works on a Western audience, which is more accustomed to the 7-tone scale.


    Thanks for sharing. That was really cool.

  • Eugene

    That’s pretty cool

  • Adam A.


    Pentatonic scales are incredibly common in the world of folk music, regardless of the region in the world we are talking about.

  • joulesm

    Hehe, I didn’t smile at 0:42 but couldn’t help it at 0:58.

  • Gordon Stangler

    Quite a display of talent and passion there. It’s nice to see a moment of levity among great minds.

  • Beatles Fan

    he should’ve done harmonies more

  • The Chemist

    It was awesome. I’m tempted to try it with a captive audience, but I’m not sure I could play that instrument.

  • Sam Gralla

    wow!! That was really cool that they got the 3rd and the 5th automatically. He had to give them the 6th. I wonder: what note would they sing below 1 if he didn’t give it to them? 7? 6? flat7?

    That would be a really interesting experiment. I would expect 6 from the Chinese, but in the western world I really don’t know.

  • Sam Gralla

    Too bad that five note riff in the intro isn’t F# instead of F =)

  • Edmund Schluessel

    The pentatonic is based around some elementary ratios of notes.

    Start with a note of frequency f, and call it 1.

    First, define an octave: two notes are separated by an octave if the frequency of the higher note is exactly twice that of the lower note. Call the note one octave above 1, 1′.

    Powers of two will give us octave separations that are, to our ear, the “same” note.

    What happens if we have a note with frequency 3f? Call this note 5′.

    Drop its frequency by an octave, and we have 5 — a perfect fifth above 1.

    What about a perfect fifth above 5? Call this note 2′ — an octave below it is 2.

    The note with frequency 4f is just 1”, nothing too interesting.

    But the note with 5f, call that 3”. Divide its frequency by 4 and we have 3.

    So from simple frequency ratios we’ve already built most of the pentatonic scale: 1-2-3-5-1′-2′-3′-5′-…

    That last note is a bit trickier. So far we’ve only tried dividing by two. Can we try dividing by 3? Sure, why not? Trisection of a length of string is a simple operation, if you’ve got Euclid on your side.

    Take (5/3)f and call this note 6.

    So now we’ve built the major pentatonic: 1-2-3-5-6-1′-2′-3′-5′-6’…

    The existence of the major pentatonic implies the minor pentatonic, which we get just by starting on a different note, 6 instead of 1.

    From here and the rules of geometric construction we’ve already practiced, we can extend the scale any of hundreds of ways. Here’s one way (of many) to build the complete Western twelve-tone scale:

    C — 1
    Db — 16:15
    D — 9:8
    Eb — 6:5
    E — 5:4
    F — 4:3
    F# — 11:8
    G — 3:2
    Ab — 8:5
    A — 5:3
    Bb — 16:9
    B — 15:8
    C’ — 2:1

  • Egaeus

    @Adam A

    You’re correct, but the 7-tone scale is not typically used in Asian folk music, whereas Western folk music uses both. Then you have the situation such as in “America, the Beautiful,” that has a pentatonic melody, but is harmonized with traditional western harmonies.

    But the point was that a Chinese audience would not have a problem with the demonstration, but would actually be more…receptive to it, since the pentatonic scale is more natural to them due to an increased exposure. If you ask a Westerner to sing a musical scale, I’d bet that at least 99% of them would sing something like do-re-mi-fa-so-la-ti-do, but that may not be the case in China.

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  • Sili

    I’m inclined to think he can only do that with sufficiently large groups. I don’t think I could hit it without prompting, but in crowd there are bound to be people with some musical training who can serve as anchors for the rest the of us. So we’re not so much individually finding the next note as we’re following the lead of those who know it.

    Easy to test of course, if anyone cared to.

  • Chaalz

    Made me smile. Agreed it is “A rare combination of joy, passion, and teaching.”

  • Mark

    @Edmund Schluessel
    But there’s a problem here that I learned about, but never found a satisfactory resolution for. If we take twelve 5ths, we should expect to end up on a C seven octaves higher. The frequency should be (3/2)^12 = 129.7, but if we go up from C by seven octaves, to the same final note, we find the frequency is 2^7 = 128. What has gone ‘wrong’?


  • Mark H.


    You’ve hit upon the problem of temperment. The ratios of notes given above by Edmund Schluessel are only used in what’s called “just intonation,” which only works if you never change key during a song. If you tune your instrument to the key of C, playing any other key will sound out of tune. Most modern instruments use 2^(1/12) as the ratio between successive notes (e.g. A and A#). This allows a musician to play any key at any time without retuning.

  • Gray Gaffer

    @20 continuing: in fact our piano tuning is a compromise across the board. And this infects all our other instruments to the extent that we – most all amateurs at least – tune our guitar or whatever to our piano. I was very surprised and impressed the first time I heard a properly tuned harmony. One which happened to be pentatonic, but there are others equally effective.

    There is quite a large body of work on micro-tuning and ‘natural’ scales. One effect that I was shown by Charles Lucy was that you need different tuning when ascending the scale vs descending. He accommodated this on his own custom guitar which had five frets per intonation point to our traditional one fret.

    Some names I know of proficient in the area:

    Charles Lucy (Google “The Lucy Scale” will find musicians using it, also must visit his site for a good practical introduction and software tips)
    John Gibbons
    Laurie Spiegel
    Jimmy Hotz

    There is also some rather delightful woo skirting reality from, e.g., G. I Gurdjieff, notably from his autobiographical story of his travels across the Gobi desert.

    To play with these things you need something like a Yamaha DX7. You could also probably use CSound on Linux. As I said above, Charles himself has a software review of relatively recent programs at

  • Ellipsis

    There’s a special place in hell reserved for Bobby McFerrin and his annoying songs.

  • Sili

    Of course there is, Ellipsis – he’ll have to be there to torture all those souls that don’t like Bobby McFerrin, after all.

  • Roby Abraham

    A shortcut to Bethowan.

  • Stacy Horn

    I was there and it was a lot of fun. I wasn’t a fan of Bobby McFerrin before (due to the Don’t Worry Be Happy song) but I am now.

  • Dave

    There was an interesting program , The Music Instinct, on PBS last week that featured Bobby McFerrin and other musicians. It examined the science of how our brains respond to music and questioned whether our response to music is hard-wired or learned. Bobby impressed me as being a very good musican and a very smart and articulate guy. It can be seen at .

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  • void()

    Weird, seems like the video was switched to another one somehow.

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About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] .


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