McCartney confirms dog whistle on album

Sir Paul McCartney has confirmed that when The Beatles recorded the Sgt Pepper album in 1967 they placed a sound in the recording that only dogs can hear.

In an interview with the BBC's Zane Lowe, McCartney was talking about the sound of vinyl and confirmed the much rumoured dog theory. "I think vinyl is the best. It just sounds good," he said.

"I asked my engineers why it sounds good and they explained that there are frequencies above and below that you can't hear. We got into a rap with George Martin a long time ago. We'd talk for hours about these frequencies below the sub that you couldn't really hear and the high frequencies that only dogs could hear. We put a sound on Sgt Pepper that only dogs could hear. If you ever play Sgt Pepper watch your dog".

The Beatles recorded a dog whistle and placed it into the track A Day In The Life. The high frequency 15 kilohertz tone cannot be detected by the human ear but will have your pooch singing to its own Beatles sound.