Z4 coupe automatic. Deep vibration sound from rear

[Edward1985]

Hi there. New member and newish owner here.
I have a 56 plate Z4 coupe automatic which has just developed a strange vibration when at standstill.
It's a very deep sound almost like bad bass sound. It can come and go. It only does it when the car is warm.
As soon as I get over 1000rpm the noise goes away.
Any ideas on what this can be?
Thanks.

 

[NickDE]

No clue. Loose exhaust vibrating ?

 

[NickDE]

And your first post is supposed to include photos of your car, we like seeing Z4C autos here

 

[Edward1985]

Here she is

 

[NickDE]

And as always with Coupes, a very good looking car. Still no clue on the noise though :?

 

[Edward1985]

Thank you.