Surround sound through my laptop?

I've been trying around for some time now, but I'm not really getting anywhere. Now to my problem. I would like to watch films on my TV (Phillips48PFK5500 / 12) with my laptop (Lenovo ThinkPad T450s / link to the Speccs below in the post). My surround system is a Logitech z906.

Now for the construction:

Since my laptop only has a mini display port, I connected it to an HDMI splitter using an HDMI adapter. This splitter leads to my TV via another HDMI cable. A second HDMI cable goes into an HDMI to Optical Out converter. This in turn goes into my system with an optical cable.

I get sound, but only stereo. Do I need an additional receiver? Or do I just have too many adapters and splitters?

Thank you for the answers to this (probably) stupid question.

Link to the laptop: https://www.notebookcheck.com/...642.0.html

(It's the version with the i7)

This is simply because your notebook only produces normal stereo output over 2 channels.

where there's no sourround sound, nobody can be heard.