It's daffy to believe the quack of a duck doesn't echo
By Steve Connor
08 September 2003
EXPERTS in acoustics have debunked one of the more esoteric myths of the modern
age - that a duck's quack is the only sound that does not produce an echo.
The myth has been promulgated as fact by a number of television and radio shows,
from Shooting Stars on BBC2 to Steve Wright on Radio 2 and John Peel's Home
Truths on Radio 4.
Now scientists have definitively shown that the quack of a duck does obey the
laws of physics and can, just like any other sound, produce an echo when it
bounces off a solid surface.
With the help of Daisy the duck and an anechoic chamber - a room with
jagged-edged walls where sound cannot be reflected - Professor Trevor Cox of
Salford University precisely recorded the exact sounds that constitute a quack.
He then recorded Daisy's quack in a reverberation chamber with cathedral-like
acoustics. This generated long reflections, causing Daisy's quack to take on a
sinister echoey sound, Professor Cox said.
"It proved that a duck's quack does, indeed, produce an echo."
The recordings were used to create simulations of Daisy performing at the Royal
Albert Hall, and quacking as she flew past a cliff face. The conclusion was that
a duck's quack definitely echoes, just like any other sound.
However, people could be forgiven for thinking that a quack does not echo
because of the way that a duck's call tails off at the end, making any echo
difficult to discern.
"The biggest mystery is why this myth should have arisen at all. One theory is
that the envelope of the duck's quack has a gradual decay, which makes echoes
difficult to hear," he said.
"A duck quacks rather quietly, so the sound coming back is at a low level and
might not be heard," said Professor Cox.