For most people, those notes are about 2 octaves apart, or about 16 notes.

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But researchers heard a nine-year-old whale named NOC make sounds octaves below normal, in clipped bursts.

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This was no Benny Goodman or Artie Shaw riffing with glissandos, over two octaves of pure melody.

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When playing octaves and difficult technical passages in big virtuoso works like those of Liszt, Prokofiev and Rachmaninoff, Horowitz could sound almost superhuman.

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In Glasgow, Peterborough and Cardiff they knew different: Mr Pitney's voice, one of the stranger instruments ever heard in pop music, swooping and aching through three octaves, was still ringing round them.

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Now, Dr Cummer and his colleagues have shown off an acoustic cloaking technique that works in air, for audible frequencies between one and four kilohertz - corresponding to two octaves on the higher half of a piano.

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This "A Taste of Honey" shows that skill in action: Playing with great whimsical spirit, Booker methodically takes apart the theme until he reaches the top two octaves of the piano, at which point he slips and slides through a barrelhouse fantasia on the theme.

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