I just picked up a really low mileage (51k) cooper S with the HK system.
The sound seems to be really flat and lacks mid range, i have adjusted to settings to no end but cant seem to get decent sound.
The other day when i hit a bump it ever so briefly sounded great and then went back to the same old flat sound.

Has anyone else experienced this issue or have pointers, i dont think the amp has failed because i have sound its just got no mid range.

Thanks

 

This has happened to me in a roundabout way, but not sure if the cause is the same. Mine was due to moisture setting in near the receiver. I haven’t serviced it yet, but will be soon! So needless to say this may or may not be of use. With my experience in aftermarket receivers and head units, sounds like a loose or bad audio connection, especially if your mini has an after market head unit or receiver. If you do have a aftermarket head unit or receiver on your mini check the connections pretty easy to do once you remove the unit from the dash. Also, if you have an after market head unit or receiver, I would see if you have a harman/kardon wire harness adapter for your head unit. This adapter connects to your cars wiring system in your dash (like a normal one) and connects your cars to your unit. Unlike the normal one the adapters the adapters that I’ve seen, besides having a large rectangular programming computer attached to the wire harness, it has a pressable button attached to the harness separate from the rectangular computer. This button when pressed amplifies the sound. Might be a stretch, but if you have a after market unit and can still use your control functions on your steering wheel then you have this adapter installed, and what might be happening is this button is being pressed fully or ever so slightly to give you that variation in sound when you hit bumps. But I’m thinking that would be a stretch but not an uncommon one. Most people tuck this wire that has a button behind the unit and never install in completely so it can be accessed without removing the unit. I’m thinking it is probably a wiring issue, or water damage. I have 2 minis one has the stock unit and the other has a after market unit with the h/k wiring harness adapter. My unit 2nd cooper had no issues on bumps with the harness, but my first cooper had issues with sound after the water damage. I prb have rust and corrosion by now so I need to handle it soon but hopefully I have been of some help or atleast narrowed down the issue. Just joined and would have responded sooner if I saw your thread, but hopefully you figured it out!