energy efficiency

I have a watt meter similar to this one: Watt Meter My speakers happen to be Magnepan 1.6 which are not very efficient. I am driving the Magnepans with a Hypex NC500x Class D amp. Which has a 93% efficiency rating or so at full power. Playing loud music thru my speakers I am measuring about...

Currently I am investigating a replacement of an older 7.1 AV-receiver (5.1 + 2nd stereo zone) to try out Atmos by adding 2 Atmos enabled speakers in 1st path to gain some 3D sound experience. Video/Music 70/30. Streaming and input sources are: 4k Apple TV, BlueRay player and for music only I...