Hey HKniceguy, nice thought!
Now I guess you can try both former CP 744 and AC 744 Combis and see if they have different sound, I'd be so interested in knowing if they have different kind of sound. I guess maybe it'll depend on the weather and weight? Anyways, it's kindda insteresting!
Also, do A343s make such noises too? A343s are far more quite than the B744s, but they still make some noises of course. Have you noticed anything about Airbus?
P.S., r u in YVR? Do you knwo any good place for plane spotting in YVR?