@ OP andAC
"Amazon hasn't promised to hand over any recordings yet just, despite this latest New Hampshire court order." Yet just??
"I finaly find out that it was the sound from the TV set or from a you tube video."
I remember complaints about a rogue app that kept the mic open and listening out for tv, radio and youtube adds in order to correlate listener/viewer data with handset owner info. I guess if they can add all the data collected on a smartphone with your computer browsing history and cookie data plus cable/satellite subscription / viewing habits you would make a pretty valuable advert target.