Home Network/AV layout during Renovation...

[Lucid]

There are specific minimum and maximum angles for the speakers (22-30 degrees for the fronts, 90-110 degrees for the side surrounds) which if you can do trigonometry and have accurate dimensions for the room means that exact positions can be calculated. There are angles for the ceiling speakers too.

I did a rough-out based on your diagram. It's risky because I couldn't be sure that the proportions were close to accurate, but given your attention to detail with the previous diagrams I felt you'd be pretty close. A l--------l represents the same distance from the side walls either side of the room. The distance depends on the room size. As a general principle though corners are bad places for speakers, so they're to be avoided. There are height recommendations too for the speakers.

One concern that I have is the lounge door. Convention says it opens in to the room. The question is on which side it is hinged? Is it planned to open against the wall or against the sofa?

 

[motorbiking]

I was about to post that since you are going back to brick, you should consider insulated plaster board on the external walls, but looking at the celotex sheets, it looks like you are doing that.

I have read articles that say you should wrap/tape cables if they are going through foam insulation. I did mine in my garden room as it seemed a no brainer for £3 worth of foil sticky tape. Holds them in place pretty well too.

 

[Adam182]

There are specific minimum and maximum angles for the speakers (22-30 degrees for the fronts, 90-110 degrees for the side surrounds) which if you can do trigonometry and have accurate dimensions for the room means that exact positions can be calculated. There are angles for the ceiling speakers too.

I did a rough-out based on your diagram. It's risky because I couldn't be sure that the proportions were close to accurate, but given your attention to detail with the previous diagrams I felt you'd be pretty close. A l--------l represents the same distance from the side walls either side of the room. The distance depends on the room size. As a general principle though corners are bad places for speakers, so they're to be avoided. There are height recommendations too for the speakers.

One concern that I have is the lounge door. Convention says it opens in to the room. The question is on which side it is hinged? Is it planned to open against the wall or against the sofa?

That is well placed concern regards the door, it was also an issue I was thinking about. I had planned to have the door open against the wall before you suggested wiring for surround this as you mention poses a problem I was thinking my options were A) Use a low profile speaker (if they even are a thing) B) have the door open against the sofa C) reposition the speaker.

Regards the room dimensions its basically a 3.98m x 3.98m square (if you imagine it without the bay window area and chimney breast) and 2.7m high.

I was about to post that since you are going back to brick, you should consider insulated plaster board on the external walls, but looking at the celotex sheets, it looks like you are doing that.

I have read articles that say you should wrap/tape cables if they are going through foam insulation. I did mine in my garden room as it seemed a no brainer for £3 worth of foil sticky tape. Holds them in place pretty well too.

Thanks for the suggestion on insulated plasterboard, on Monday I took delivery of 25 Gyproc 38mm PIR backed plasterboard for all external walls. I do plan to still chase all runs though seeing asthough mess isn't a problem right now.

 

[Lucid]

There are low profile on-wall speakers. Monitor Audio Soundframes take up about 80mm depth. They're around £225/pr. KEF T101 are slimmer. They takes up less than 40mm and they're around £300/pr.

In the diagram and the pictures it looks like you have a small return to the side of the casement. Depending on how far you build the walls out there may be some space between the side wall and the door at 90 degrees hinged on the edge facing the room corner. Given that you'll need a door handle and probably a stopper on the floor to prevent the handle bashing the wall as the door opens out fully, then it's possible you could fit an 80mm depth speaker behind the door. If that's the case then the used KEF speakers I have in mind for you would fit (75mm depth inc wall bracket) and the whole 5.1 package of centre, fronts, surrounds and sub would cost you less that just one pair of the 40mm KEFs.