Your computer or the AE could have been locking into a legacy and/or overloaded WIFI network.
I had a similar problem recently, but the cause was far more obvious... the noise started right after I replaced my generic "had it laying around" optical cable with a fancy new optical cable that turned out to be defective or was damaged during shipping.
I had a similar problem recently, but the cause was far more obvious... the noise started right after I replaced my generic "had it laying around" optical cable with a fancy new optical cable that turned out to be defective or was damaged during shipping.