Planning a Viewing Room: The Decisions That Are Hard to Undo

The decisions that cost money to fix after a room is finished are not the ones about which television to buy. They are the decisions about where to put the television, how to run the cables, whether to add acoustic treatment and where to position the seating. These are structural choices. Getting them wrong means either living with the result or paying a tradesperson to undo decorating work.

This guide covers the planning decisions worth making before paint goes on walls or flooring goes down — not because the results require elaborate installation, but because the later you make these decisions, the more constrained your options become.

Screen position

The screen position determines everything else: viewing distance, seating position, cable routes and acoustic treatment placement. It is worth establishing as the first decision rather than the last.

The central question is which wall. In most rectangular rooms, the screen goes on a short wall to allow the greatest seating distance. The exceptions are rooms with windows on the short walls — placing a screen opposite a window creates a reflection problem that is difficult to manage without complete blackout covering. Where the short wall has a window and the long wall does not, a long-wall placement may produce a better viewing result despite the reduced depth.

Screen height deserves deliberate consideration. The ideal viewing position places the centre of the screen at or slightly below seated eye height — approximately 100–110cm from the floor for a seated viewer. Wall mounting at this height looks lower than many people instinctively prefer, because the instinct is calibrated by standing, not sitting. A screen mounted so the centre is at 140cm from the floor requires a sustained upward head tilt that becomes uncomfortable in extended viewing.

Seating geometry

The primary seating position determines what the room is optimised for. In rooms with multiple rows or seats at different distances, there will be a primary position — usually the central seat in the closest row — and secondary positions. Acoustic and visual calibration is done for the primary position; secondary positions necessarily compromise.

The viewing distance from the primary seat to the screen should be established from the screen size calculation before fixing the seating position. Working backwards: if the room allows a 3.5m depth and the screen size calculation recommends a 3m viewing distance, the sofa goes at 3m and the television goes at the far wall — not wherever the television fits most conveniently.

Most people place the sofa first and buy the television second. The better order is to establish the viewing distance first, then select the screen size that suits it. The sofa can move; the wall cannot.

Cable routing

Cable routing through walls requires either chasing (cutting channels in the plaster), using conduit during construction, or surface trunking. The first two require access before the room is finished; the third is always available but visible.

The cables worth routing before decorating: HDMI from screen position to equipment location, mains power to the wall-mounted screen position, and speaker cable to surround speaker positions if a multi-channel system is planned. A single conduit containing all three — even if only used for HDMI initially — avoids retrofitting work if the system is expanded later.

Planning for a minimum of two HDMI runs to the wall position is worth considering even if only one source is connected now. HDMI standards change; having a spare run means replacing a cable rather than replastering.

Light control

Window treatment is the highest-impact change available to most viewing rooms. The guide on viewing environment covers this in detail from a calibration perspective. From a planning perspective, the point is that window treatment decisions made during room design are cheaper and better-integrated than retrofitted solutions.

Blackout lining on curtains or blinds is the most effective option for windows that affect the viewing area. Electric blackout blinds, while more expensive, allow light control without leaving the seating position — worth knowing for rooms that serve multiple purposes and need to transition between bright and dark conditions.

Acoustic basics

Home cinema acoustic treatment does not require specialist installation or significant expense to make a meaningful difference. The acoustic problems in most domestic rooms are first reflections — sound bouncing off walls, floor and ceiling before reaching the listener — and low-frequency room modes that cause certain bass frequencies to build up or cancel at specific positions.

First reflection points are the locations on the side walls, ceiling and rear wall where a mirror placed flat against the surface would reflect the front speakers towards the listening position. Soft furnishings — sofas, curtains, rugs, bookshelves with irregular surfaces — at these locations reduce the intensity of first reflections and improve intelligibility without requiring acoustic panels.

A rug on a hard floor between the screen and the seating position is the single most cost-effective acoustic treatment available in a typical room. It addresses the most significant reflection point — the floor bounce — without requiring any wall treatment at all.

Ventilation for equipment

AV receivers and amplifiers generate substantial heat in operation. Equipment placed in closed cabinets without ventilation will throttle performance or fail prematurely. Cabinets that house AV equipment need either open rear panels, ventilation holes aligned with natural convection paths, or active cooling. This is worth knowing before a bespoke joinery unit is built around the equipment without provision for airflow.