2011 Mini Cooper S Countryman: does YOUR premium sound system hiss when it is TURNED OFF?!

mini
cooperscountryman

#1

Hi. 2011 Countryman, bought new from the dealer. We’ve had it for a year and a half. Premium sound system has audible hiss when the radio is turned off. Also when the car is turned off. Also when you unlock the car, get in, shut the door, but don’t put the key fob into the slot.

Note that the RADIO IS NOT TURNED ON. The CAR IS NOT TURNED ON. But there is still an audible hiss in all speakers, front and back. I’m 60 years old: if my aged ears can hear the hiss, it is probably not subtle.

Clearly the power amplifier is powered on when the remote unlocks the doors. Possibly also when the doors are opened. Also after the car is turned off – even if the key fob has already been removed from the slot.

We have taken the car to the dealer multiple times to resolve this. Hiss remains. Dealer says this is a known design flaw, that Mini knows of the problem, and is “working on a solution.” Hm. No solution in over 6 months. Hiss still pronounced and present. I guess Mini is not working very hard on the problem.

Seems to me that a “premium sound system” should not have audible hiss at any time. Especially when it is NOT TURNED ON.

Am I the only owner with this problem? Does your Mini’s premium sound system hiss when it is turned off?


#2

That’s pretty sloppy design.

That radio is likely just the front end. It likely has a power amp in rte trunk or hidden somewhere that is powered when the key is on. The radio being off, the input of the amp is left floating but turned on so it likely is picking up electrical junk or makes its own junk.

If you’re handy with wiring and electrical stuff, you use the power swtched output on the radio (most have them) and short the output from the radio to the amp to ground so that when the power is off, the radio is shorted. You could use this voltage to switch this relay. The contacts of that relay in turn shorts the ouput of the radio when the raduo is off.
Optionally, you could turn the power to the amp off using another contact or larger power relay.
Long store short, it is a bit involving.


#3

I don’t have a Mini. But on my 2006 Chrysler the audio system is also used for the integrated phone, nav system, and some other audible alerts. The amp doesn’t seem to power up until an alert occurs–you can hear it come on slightly before anything comes out of the speakers, then it seems to shut down, or at least is muted such that I hear nothing unless the stereo is on.

It may be that you have a defective amp that isn’t powering down, or some component in the chain that powers the system is malfunctioning and not allowing it to shut off. It may have also been wired wrong from the factory–hard to do with interlocking connectors, but stranger things have happened.

Your factory radio is unlikely to have an accessible “power switched output” unless you have a wiring diagram and dig into the wiring loom. And I would avoid shorting anything to ground intentionally unless the circuit has been designed to handle it–you’re likely to either blow some fuses or blow the solid-state controller that turns the amp on and off with the radio.

I’m pretty handy with electronics, but due to the complexity of modern audio systems, I would probably let the dealer handle this one, especially if the car still has any kind of warranty left.


#4

Shorting an input is fine when there’s no signal present and the radio is off. That’s actually a very common way to muting high gain amplifiers and make sure they don’t go into oscillation.
I think Mini uses Harmon/Mark Levinson equipment. Surprising they threw that design over the wall with the amp hissing if it is a common problem.


#5

I had a “high end” BOSE radio/CD player in a Corvette that did this. It was repaired by a local car stereo shop in town. it turned out to be a bad/incorrect capacitor in the amp. That’s all I remember but it may be a starting point for you.


#6

This is normal. The speakers and bluetooth hardware power up when you open the doors. They turn off after 5min or so if you don’t start the car, or they turn off immediately if you lock the car from the outside.