Daz, I’m quite sure you’re right, but to judge from the sound that comes off the video it’s a lot more noticeable that in other, principally Rolls-Royce engines.
There again, I’ve got a copy of Gibbs-Smith’s wartime aircarft recognition manual in which he warns against identifying aircraft by the sound they make. There are, he says, one or two exeptions including the Spitfire (when it whistles). So perhaps my memory’s playing tricks after all.
Herein lies the material for a new thread – I remember from my teenage years that the Aer Lingus Carvairs had a subtly different engine note from the bog-standard Ace Freighters DC-4s that used to frequent Liverpool in 1960s. The boom of a British Eagle Britannia doing ground runs used to rattle the windows of most of south Liverpool, while the turboprops of today(748, ATP, F-50, ATR-42 and the odd Electra and An-24) all have their own sound.

William