Harman Kardon 5.1-Kanal Surround-Lautsprechersystem – Schwarz

The system is working very well as a surround system, but I´m very disappointed when listening to music.
I had some doubts about this system since there are many reviews telling it´s not working well. But I gave it a try with the possibility to use a Soundsend or Axiim Link transmitter instead of the included transmitter, if it turned out not be working well. Because this system is using WiSA enabled speakers according to the Harman Kardon specifications (but I cant find any labels/information on the speakers telling anything about WiSA?). Maybe I don´t need to buy a Soundsend because it´s working pretty well these three days I have been using it.
The Surround feeling from a movie streamed from a good streaming service is amazing. Even some Dolby Atmos labeled content gives a stunning performance, even though Harman Kardon says it doesn´t support Dolby Atmos. I like bass, and having the subwoofer placed under the couch, gives the bass a good punch! I have almost only used it without the „fake“-surround button pressed.
But sadly I cant get any music feeling at all. It totally lacks the details and it sounds like a blury background mess in my opinion. But maybe it´s some calibration and setup I need to do? If I remember right, other seems to be very pleased with the sound of music from the system, when it worked for them?
Every early morning it looks like the system starts it self, probably for an update check. It have done so all three nights sometimes between 03.00 – 06.00, so when I get up in the morning all speakers are lit and I have to push the off button twice to put the speakers to sleep again. The system says that the last update is from some time 2020 (mars?), and I have manually pressed „Update“ on the box two times, and it looks like it´s doing an update that takes about 2 minutes.
I have other wireless systems like on/off-switches and for another wireless subwoofer transmitter behind the same bookshelf-door, and the main WiFi-mesh-router is about 2m away. But most of the time, there is no connection problems. The second evening there was some strange drop outs about three times within 10 minutes. But that´s all! Rest of the time it´s been working rock solid with the only problem that it starts it self every morning.
One strange thing: When I listened to three different YouTube tests for 5.1-systems, there is no sound from the rear speakers when the test-movie shows there should be sound from them! Instead the sound comes from the corresponding front speaker! But when looking on movies, it sounds perfect!