I purchased a 2011 Legacy Limited a few months ago. It has the Kenwood OEM head unit with nav + the Harman Kardon amp/speakers.
I didn't realize until after the purchase that the system emits some kind of RFI around 6.5khz. This isn't the normal noise floor deal. This is something on top of the noise floor. Also the amp was pumping at low volumes because of variable gain.
I contacted HK and one of the engineers responded, offering to replace the amp. They shipped one immediately. The gate time was much longer, and that completely eliminated the pumping issue.
NOTE: The engineer at HK has been great. They have provided excellent customer service. They really are trying.
However, what I presume to be RFI remains. So I guess this means that either a) there is a poorly placed cable (near some source of RFI) or b) there is a problem with the Kenwood OEM head unit.
Anyone else with this problem?