Hi All,
I recently purchased a new BMW 340i with the "premium" Harman Kardon Logic 7 sound system. As you might expect, the audio system is less than advertised. In any case, I'm having a problem with the system and the dealer techs can't figure it out. The left front channel appears to be distorting and cutting in and out periodically, but I haven't been able to reproduce it for the dealer. There is always distortion present during audio playback from any source (CD, iPod, and satellite radio)...and on a few occasions it almost sounded like the speaker was cutting out completely, almost like a loose connection. But what I was able to do was, using a signal generator and speaker distortion meter, determine that only the left front channel is distorting. The distortion occurs primary at 250 and 500hz signals. Listening to the left front speakers (25mm tweeter and 100mm woofer), it appears both of the speakers are distorting at these frequencies.
So my question is this: based on the above indications, where do you most likely believe the problem lies?
1. Failed or defective speaker(s) (seems unlikely since both the tweeter and woofer appear to be distorting - these are separate speakers).
2. Wire or grounding issues (again, seems unlikely since these are separate speakers and the distortion only occurs at certain frequencies).
3. Amplifier/DSP issues (my conclusion, based on elimination of the above two).
The amplifier/DSP is a combined unit in the back of the car with no manual adjustments possible.
Thanks for helping me figure this out!
