Thank you for your reply gents.
I normally just used the streaming functionality (Spotify connect/Music cast) to play music via Wifi. I had the TV permanently connected via the optical in and didn't use the PC to play music. I don't have any analogue sources.
I suppose I could set up a mini PC to stream music and configure it with a software equaliser for loudness but it will not be as convenient.
Considering the cost of a PC / screen / peripherals & space, would I be better off getting a DAC (with good Bluetooth) + Stereo power amp & a separate used AVR receiver with loudness control? How would I connect speakers to both? I ask this, because when watching movies, the stereo system does not result in clear dialogue so I thought later down the line I would get a mid-range sound bar.
@Godataloss - thank you, but the MiniDSP SHD is a bit out of my price range.