I've gone from surround off to surround low. Recently, for most FM stations, I've started noticing that the sound goes as if from stereo to mono and back randomly. The volume drops (in mono-ish mode) as well. Is this related to my surround setting? Is there a bug/service bulletin? I guess I'll go back to surround off when I take the car out again and pay more attention (in the weekend
).
My 2003 330i had this problem - it almost makes me think - another german common supplier problem. BMW published an obscure service bulletin and they would replace your tuner.
AP (whatever it stands for
) is off.
This is normal according to Porsche. The CDR-24 manual mentions that the surround mode maybe compromised due to reception and multipath issues. My Boxster and Cayman both did what you described. I believe the other feature you mention is the volume gets louder when road noise increases.
There are a few threads on this and I wish we could get a better answer. Several people, including me have been told by the dealer that they have never heard of this. I also get the same issue using my wired FM ipod connection so it can't be due to multipath or reception issues. I use my radio (or ipod) every day so this issue drives me nuts. My AP is off but I think its actually going in and out of surround sound not stereo to mono. But either way, when this issue goes into effect the stereo certainly sounds like ****.
Of course its difficult for us to understand as we are not able to hear the surround sound in each others car however, when my surround sound is on it seems the rear speakers at times just fade out and then slowly fade back in.
Does it seem this is what everyone is experiencing?
This seems to make sense with what tme110 stated about it happening with his ipod connection.
I have the same issue in my '07CS w/ CDR24 + Bose.... very annoying.
I am pretty sure that there is language in the manual for the Bose audio system that says something to the affect that surround sound capability was "optimized for digital media". I take that to mean that radio, where the signal can bounce around a bit, may produce unexpected results, whereas CD's should be fine.
I never use FM, so I have no direct experience with the issue, but I can say that using Sat Radio or CD's as a source does not produce any sort of image instability.
I will also offer that, like many users, Audio Pilot is not always invisible. When tooling around town, it seems to be way too noticeable, but when on an extended highway drive, it seems to work well. I take it that the system was designed to deal unobtrusively with steady state cabin noise rather than more rapidly changing conditions like one would get around town with the windows open.
Brian
It still amazes me that dealers have never heard of this issue.
"Surround sound" in the stock Cayman systems is a derived multi channel sound system -- meaning that the surround processor depends on a stereo signal to "extract" out of phase and other surround information and steer them to the rear speakers. This is how Dolby Pro Logic and all it's variants work. With FM radio listening, due to just the way radio reception works, when the signal gets weaker (or there is interference) the radio tuner automatically switches to mono -- which yields less "noise" for the listener but does condense the stereo field to mono. As a result, the surround processor loses the requisite "stereo out of phase information" and therefor has nothing to process. That is why the sound disappears from the rears then comes back. This is an issue with FM reception, not surround processing.
Perhaps the FM tuner in stock Caymans is inferior, or most other cars everyone here has experience with does not use surround sound to derive the rear speakers but instead sends the same signal from the L + R fronts (even mono) to the rears.
Net-Net I do not think this is an issue with the Cayman stock system surround processing -- the only blame would be on a poorer quality FM tuner which is less adroit at handling adjacent channels, multipath interference, etc..
Bingo !!!!!!!!!!!!!!!....I just had an "ah hah" moment.... this is an antenna issue. I recall having the same problems with my Ferrari F355.
That little wire in the windshield is insufficient to capture sufficient signal strength depending distance from and orientation of the car to the transmitting antenna....I'll bet the car's A pilars can block enough signal to cause the shift to Mono...
So, where do I mount an old fashioned antenna? Front fender? rear fender? Left or right side?
