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Which Cables to Run First: The Cost of Retrofitting
2026-11-11 · Product News
Home theater wiring is the step where, before the ceiling is closed up and the walls are skim-coated, you bury the cable from the amplifier to every speaker and every power point inside the walls. Get this step wrong and the problem later is not that it won't tune well — it's that you can't change it.
Key points
- Four runs have to be settled together: ceiling to TV cabinet, TV cabinet to rear wall, TV cabinet power, subwoofer power.
- Run 5 cables for 5.1, 11 for 7.1.4, plus 1–2 spares.
- At least 4 five-hole sockets at the TV cabinet, and one on its own at the subwoofer position.
- Speaker cable from 2×1.5mm², PVC conduit φ20, 30–50cm extra at each end.
- If you miss one, there are only three ways out: surface trunking, skirting board, wireless.
Before the boards go up, all four runs have to be settled at once
The cabling in a home theater is only ever two kinds: signal and power. Signal goes out of the amplifier to the speakers in the ceiling and the surrounds on the rear wall; power comes from the distribution box to the TV cabinet and the subwoofer position. Four runs — miss one and it isn't a 5.1.
The order can't be reversed: fix the equipment first (how many channels the amplifier has, how big the subwoofer is), then the positions, and only then the cable. Run cable "by experience" and one equipment change leaves you a run short. However carefully the home theater design is done, it all has to land on this list.
| From → to | What to run | How many | Length and slack | If you miss it |
|---|---|---|---|---|
| Ceiling → TV cabinet (amplifier to ceiling junction box) | Speaker cable 2×1.5mm², in PVC conduit φ20 | 5.1: 5; 7.1.4: 11 | 3–8m along the route, 30–50cm extra at each end | Surface trunking, or switch to wireless |
| TV cabinet → rear wall (surrounds, rear surrounds) | The same spec speaker cable | 5.1: 2; 7.1: 4 | 4–9m, 30–50cm extra at each end | Move the surrounds to in-ceiling, or go wireless |
| Distribution box → TV cabinet | 2.5mm² copper cable, dedicated circuit | At least 4 five-hole sockets | 30cm above the floor, 5–10cm clear behind the cabinet | Surface-mounted sockets, power strip |
| Distribution box → subwoofer position | 2.5mm² copper cable | 1–2 five-hole sockets | 30cm above the floor, at the subwoofer's actual position | Power strip run out, surface-mounted |
The cost: settling all four runs at once means fixing the equipment models, the positions and the subwoofer's exact spot before the boards go up, which pushes the schedule back a day or two. Hand it to the installer to run "by experience" and the cost is finding out a run is missing three months later — when the skim coat is already on.
Ceiling to TV cabinet: 5 cables for 5.1, 11 for 7.1.4
What to run: oxygen-free copper speaker cable, starting at 2×1.5mm²; any single run over 15m goes 2×2.5mm². The jacket should carry the spec and the length in meters; anything marked only "audiophile cable" doesn't count.
How many: 5.1 is left, center, right, left surround, right surround — 5 cables; 7.1.4 is 7 at floor level plus 4 overhead — 11 cables. Add 1–2 spares so that adding a height channel later doesn't mean opening the ceiling again.
How long: measure from the amplifier position to each ceiling point along the actual route, not as the crow flies; leave 30–50cm of slack at each end for the bends.
If you get it wrong: cable that's too thin, too many cables in one conduit, a run left too short — all of it can still be fixed before the boards go up; after that you're down to surface trunking and wireless. This is also where the value of invisible cinema speakers hinges — a length of cable out in the open cancels out the "invisible" part.
The cost: all 11 cable ends pile up behind the TV cabinet, and terminating, labeling and fault-tracing is more than twice the work of a 5.1. The more cables there are, the easier it is to plug in the wrong one — and the money saved on labels comes back with interest at rework time.
TV cabinet to rear wall: 2 to 4 surround cables, and never in the same conduit as mains
What and how many: the same spec speaker cable. Two surrounds, 2 cables; a 7.1 with rear surrounds, 4 cables.
How to route it: up the wall from the skirting board, or down from the ceiling. No horizontal chases in a load-bearing wall, and even in a non-load-bearing wall keep the horizontal chase under 50cm — beyond that, route it through the floor or the ceiling instead. Keep at least 30cm away from 220V power conduit, and if the two have to cross, cross at 90°; mains-frequency interference gets into signal cable right here first.
How long: put the exit points on both sides of the sofa, 30–40cm above the floor, still reachable when the backrest hides them; 30–50cm extra at each end.
If you get it wrong: with nothing in the rear wall, those surrounds can move to the ceiling, where the angle goes from "at ear level" to "overhead" and the imaging goes with it; or that run becomes wireless.
The cost: the economics here are lopsided — run it and never use it and you're out a few dozen yuan of cable; don't run it and the surrounds have to move. The "might not be needed" hole is usually the first thing cut from the budget, and it can't be added back afterward.
Two power points: 4 sockets at the TV cabinet, one on its own at the subwoofer
The TV cabinet has to carry four things: the amplifier, the player (Blu-ray, set-top box or wireless module), the powered subwoofer and the router. At least 4 five-hole sockets, and splitting them across two circuits is safer: one dedicated circuit in 2.5mm² copper, not sharing a breaker with the kitchen or the air conditioning.
Sockets 30cm above the floor, with a 5–10cm gap behind the cabinet so the back panel doesn't jam against them; amplifier and player power cords are usually 1.5–2m, so set the positions from the actual footprint, not from "about there" — get it wrong and you're adding surface-mounted sockets and a power strip.
The subwoofer one is the easiest of the four to forget. Which corner the subwoofer ends up in often isn't settled during the renovation, so a five-hole socket in each of two corners is safer. The height is the same 30cm or so, and it has to stay pluggable even with the subwoofer in front of it.
The cost: power is the one run of the four with no alternative. Too few sockets, blocked by the cabinet, pinned under the subwoofer — the result is a power strip trailing from behind the cabinet onto the floor. That rework doesn't go into the renovation quote; it goes into every day after you move in.
Cable and conduit: three numbers, fixed once and for all
Speaker cable: 2×1.5mm² and up, oxygen-free copper; over 15m for a single run, or driving low-impedance speakers, go 2×2.5mm². Don't use 0.5mm² "contractor" cable on a 20m run — resistance climbs and the bass goes soft first.
Certified HDMI 2.1 cable: both 4K120 and 8K60 ride on this one cable, and the 48Gbps of bandwidth is not a gimmick. A pre-buried HDMI cable has to be replaceable: run it in conduit of φ20 or larger, leave access hatches at both ends, and never bury it straight in concrete. It is the most failure-prone cable in the whole system — stress on the connector or too tight a bend radius shows up as picture trouble first.
Conduit: pre-buried PVC conduit φ20, 2–3 speaker cables per conduit and never more than 40% fill; use swept bends, not 90° elbows. For a conduit carrying HDMI, φ25 is safer.
Length: 30–50cm extra at each end, measured along the actual route. Going around ceiling joists and around the cabinet back panel all eats length, so a straight-line measurement always comes up short.
The cost: conduit and cable gauge are the easiest places to save and the ones you regret most. Going from φ20 to φ25 is a few dozen yuan per conduit; when the HDMI connector won't pass through, the fix is a hole in the ceiling. A few hundred to one or two thousand yuan extra on pre-wiring is a one-time expense; the few hundred you saved gets repaid in thousands later.
If you missed it: three ways out, three different prices
Finding a run missing after the ceiling is closed is the most common regret in home theater wiring. There are only three ways out, listed from cheapest to most expensive.
Surface trunking. 20×10mm PVC trunking stuck to the wall, a few dozen yuan a roll and half a day of labor. Cheap and ugly — a strip of trunking climbing a white wall from the TV cabinet to the ceiling, and there's no way around it. If the room is already lived in and you only need one or two runs, this is what you accept.
Skirting board or door casing. Take off the skirting, hide the cable in the gap between skirting and wall, then refit it. Some damage is unavoidable: the skirting may snap, the skim coat needs patching, the door casing has to be re-caulked. A few hundred to one or two thousand yuan in materials and labor, two to three days of work, and the furniture has to be moved.
Go wireless. SNAIL POWER CW90 runs on a dedicated 5.8 GHz link, so the stretch from amplifier to speaker needs no cabling at all — the ceiling only needs a Ø90mm cut-out. The full set is ¥17,200, with the entry configuration from ¥17,200, including five CW90s, one subwoofer and the wireless module. CW90 is a 2.75-inch full-range driver plus a passive radiator, 90W each, 111dB, faceplate Ø105×100mm (Dolby Atmos and DTS:X certification in progress). The Mini in the same series takes a Ø80~85mm cut-out, faceplate Ø91×82mm, 111dB, and is installed the same way.
The barrier with wireless isn't the price, it's whether the ceiling can be cut. A drywall ceiling has joists and services inside it, so the position has to be scanned before cutting; a modular ceiling with aluminum panels is actually easier. This is also the compromise showing up more and more in living room home theater audio: don't chase fully wired — fix the positions first.
| Option | Materials and labor | Damage | Prerequisites |
|---|---|---|---|
| Surface trunking | A few dozen to two or three hundred yuan | One more strip of trunking on the wall; no structural work | A wall it can be fixed to, and a length you can control |
| Skirting board / door casing | A few hundred to two thousand yuan | Skirting, skim coat and caulking all need repair | Skirting that can be removed; 2–3 days of work |
| Wireless CW90 | Full set ¥17,200, from ¥17,200 for the entry configuration | A Ø90mm cut-out in the ceiling for each speaker | A ceiling that can be cut; power already in place |
The cost: none of the three puts things back the way they should have been: trunking is cheap but always visible, skirting leaves marks from being taken off and refitted, wireless means cutting holes and replacing the whole lot. The difference isn't whether it can be rescued — it's whether you're willing to look at it every day.
Who shouldn't buy it: if the ceiling is already closed and you don't want cut-outs, skip the full wireless set; on a budget under ¥10,000, wired pre-buried conduit plus an entry 5.1 is better value; if you rent and might move at any time, cutting holes in someone else's apartment isn't worth it.
Who shouldn't agonize over pre-wiring: anyone whose renovation is already finished, anyone renting, anyone on a budget under ¥10,000. Studying how 11 cables should run has very low returns; the budget is better spent on the subwoofer and on calibration.
One-line test: pre-wiring costs a few hundred to one or two thousand yuan extra, fixing a miss costs several thousand, and wireless can save you but needs a ceiling you can cut. Four runs drawn on the plan are far cheaper than asking "can it still be fixed?" after the install.
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#HomeTheaterDesign #LivingRoomHomeTheaterAudio #InvisibleCinemaSpeakers #RenovationWiring #PreBuriedWiring #CW90
Written by Digital Xiaoniu, first published on the SNAIL POWER official site, Product News.