Whistle when revving at medium revs

[Ez2203]

Hello, I’ve got a 2010 vw scirocco 2.0 and when revving and medium revs there’s a whistle, the car drives fine all the power is there as is should, it stops when the engine is warm and doesn’t happen on low and high revs, it doesn’t sound like a boost leak whistle though and I have checked for a boost leak and all looks fine, had anyone had the same issue or have any idea what it can be as I’ve looked at pretty much everything? Many thanks