Do I need an AV receiver with this system?

No. The amplifier is part of the package, so you connect your TV, console or disc player straight to it. You do not add a separate receiver.

How many devices can I connect at once?

One over HDMI and one over optical, plus Bluetooth. There is no HDMI pass-through, so with several sources you switch inputs on the TV and run a single cable to the system.

Does it decode Dolby Atmos?

It has 5.1.2 channels, with two height speakers for overhead effects. Check the box and manual for the exact formats it accepts before relying on a specific Atmos source.

Will it calibrate itself to my room?

No. There is no automatic calibration, so you set speaker levels and distances yourself using the remote and the on-screen or front-panel menus.

Can I stream music to it?

Yes, over Bluetooth from a phone, tablet or computer. There is no Wi-Fi, no app control and no built-in music service support.

What comes in the box?

The five main speakers, two height speakers, the subwoofer, the surround amplifier, a remote and the speaker cables. Check the listing for the exact cable lengths included.