"[A Day In The Life] being the last song on the album, The Beatles found an interesting way to close it out. After the final note, Lennon had producer George Martin dub in a high pitched tone, which most humans can't hear, but drives dogs crazy. This was followed by a loop of incomprehensible studio noise, along with Paul McCartney saying "Never could see any other way," spliced together. It was put there so vinyl copies would play this continuously in the run-out groove, sounding like something went horribly wrong with the record. Kids, ask your parents about vinyl." -Annoymous comment on http://www.songfacts.com/detail.php?id=129
The 15 kHz "dog whistle" is limited by sound recording and reproduction limitations. Humans can hear up to 20kHz, but lose that range with age and ear damage. Sounds above 10kHz normally must be cranked out at a high volume, or decibel level, for most humans to perceive the sound. Not only are dogs able to hear these frequencies at lesser volumes, they can actually hear up to 45kHz, well above our human threshold of hearing. (http://www.eeggs.com/items/38179.html)
Madsen, Charles H. & Madsen, Clifford K. (1997). experimental research in music. Raleigh, NC: Contemporary Publishing Company of Raleigh, Inc.
Madsen, Charles H. & Madsen, Clifford K. (1997). experimental research in music. Raleigh, NC: Contemporary Publishing Company of Raleigh, Inc.