I'm not sure I'm following 100% with moving the screen and front right speaker to the left to assist with rear surround and rear right overhead separation. If you were to go with the 55 degree options, then this would place the rear overhead and rear surround at about 1400mm apart and provide adequate separation. Your rear surrounds should technically be no more than about 1.3m high (if your fronts are about 1m tall). There's not a specific measurement that the speakers should be separated by, it's more recommendations on speaker heights and angles. Personally, I like the overheads being closer to me anyway. In that case, I'd be aiming more towards the 55 degree measurements. Keep in mind that if you go for 45 degrees and move back 250mm to 4m, that means you will only have 140mm from rear overheads to the rear wall, which won't be enough as this is about the radius of the speaker. If you move your main listening position 250mm back then add 250mm to each of those measurements (-250mm for distance to rear wall). If you are looking to sit at 3.75m then the distances for the angles look like:Д¤5 degrees = 2330mm from front wall to front overheads, 5170mm from front wall to rear overheads (390mm to back wall)ДҐ0 degrees = 2560mmВ from front wall to front overheads, 4940mm from front wall to rear overheads (620mm to back wall)ДҐ5 degrees = 2755mmВ from front wall to front overheads, 4745mm from front wall to rear overheads (815mm to back wall)

Dolby atmos 5.1 4 speaker placement