This is a 100yr old cottage that the wife and I bought in the summer. As well as general updating, we decided to build an en-suite bedroom and an office into the loft, which involved lowering the ceilings by almost 2 feet and removing a chimney breast to make way for the stairs (original wall pictured below)
Additionally, a rather silly lobby affair (see below) reduced the original room size by 6' x 3' so that was ripped out, too - leaving a much easier-to-use square room about 18' x 13'
For sound-insulation and positioning reasons, it was decided that we'd place the AV system on the new wall created 'under' the stairs, with the cupboard behind allowing access to conduits etc.
The lowering of the ceiling 'issue' (although very VERY messy) gave me the opportunity to hide away speaker cables for the Tannoy SFX 5.1's (my dear wife has never been fond of visible cabling!)
The understairs cupboard idea proved invaluable as a number of additions and changes were necessary, re: cabling etc.
Having had a traditional CRT TV for many years, it was nice to upgrade to a flat-screen LG, with the built-in Freesat cutting down on boxes (by 1!) and allowing for a bit of future-proofing, too.
Much forward planning was needed regarding the conduits and plates to ensure those cables were hidden away as much as possible (please see pic).
Once the new wall was plastered and wall-papered (nice subtle black on from B&Q) everyhting just slotted into place.
The only addition I'm considering is some lighting for behind the speakers ... a bit problematic with the black wallpaper, but it's not a major issue.
This is the back of the room with the lovely little Tannoy surrounds on show!