[ergoyo]

I started hearing a low hissing sound coming from my rear speakers and very noticeable in the morning when cold and somehow related to the exhaust. The hissing varies as the revs change. It is heard regardless of the source setting on the radio, and it does not increase with the volume, so when volume is up on any source (radio, sat, cd, etc), the hissing is then disguised and faded, but continues in background.

At the same time, my BT phone voices are now "crackling" on the center speaker. WTH?

e90 335i Pre-LCI