How to install outdoor speakers
Most garden speaker installs take an afternoon with a drill, a masonry bit and a reel of speaker cable. Here's the order to do it in, the cable size to use, and the mistakes that make speakers sound thin or fail early.
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What you need
Parts
- A pair of outdoor speakers, such as the Polk Atrium 6
- An amplifier: a Bluetooth amp if you want to play from your phone
- Speaker cable long enough for the route, plus 10 to 20 percent
- Wall fixings suited to your wall
- Exterior silicone or sealant
- Cable clips, and conduit for exposed runs
Tools
- Drill with a long masonry bit (about 8 to 10 mm)
- Pipe and cable detector
- Spirit level and tape measure
- Screwdriver and wire strippers
- A ladder, and someone to hold it
Step by step
- Plan where the speakers go
Mount them about 2.5 to 3 metres up, under an eave or soffit if you can, so they're out of the worst rain and midday sun. Space a stereo pair 3 to 4 metres apart and aim them down towards where people sit, not over the fence.
- Plan the cable route
Find the shortest route from the amp, through the wall, to each speaker. Measure it, then add 10 to 20 percent for slack and drip loops. A shorter run means you can use thinner cable.
- Pick the right cable size
Use the table below. For runs outside, use cable rated for outdoor or direct burial use, or run indoor cable inside conduit, because ordinary cable sheath breaks down in sunlight.
- Drill the hole through the wall
Check for pipes and mains cables with a detector first. Drill from inside, sloping slightly downwards towards the outside, so water runs away from the house rather than in. A long masonry bit of around 8 to 10 mm is enough for two speaker cables.
- Fit the brackets
Screw the brackets to the wall with fixings that suit it: wall plugs and screws for brick or block, cavity fixings for cladding. Use a spirit level. Most outdoor speakers mount with the cable connection at the bottom; keep it that way so water can't pool in it.
- Run and connect the cable
Feed the cable through, then leave a small downward loop just before it reaches each speaker (a drip loop) so rain runs off rather than along the cable into the terminals. Strip about 10 mm of insulation, then connect + to + and − to −. One core of speaker cable is marked with a stripe or text: use that one for + every time.
- Seal the hole
Fill the gap around the cable on the outside with exterior-grade silicone or sealant to keep out water and insects.
- Connect the amp and test
Connect the left speaker to the amp's left output and the right to the right, matching + and − again. Start at low volume. If the bass sounds thin and the sound seems to come from nowhere in particular, one speaker is wired the wrong way round: swap its two wires at one end.
Which speaker cable to use
| Cable run (amp to speaker) | Cable size |
|---|---|
| Up to 15 m | 16 AWG / 1.5 mm² |
| 15–30 m | 14 AWG / 2.5 mm² |
| Over 30 m | 12 AWG / 4 mm² |
For 8-ohm speakers. Thicker cable loses less power over long runs. For very long runs or lots of speakers, ask an installer about a 70 V or 100 V line system, which is built for that job. Our calculator works out the size for your run.
Common mistakes
- One speaker wired backwards. Thin bass and a vague sound. Swap + and − on one speaker.
- No drip loop. Rain runs along the cable into the terminals.
- Indoor cable left in sunlight. The sheath cracks within a few years. Use outdoor-rated cable or conduit.
- Speakers aimed over the fence. Less sound where you sit, more complaints from next door.
- Two pairs on one amp without checking. See running more than one pair.
FAQ
How high should outdoor speakers be mounted?
About 2.5 to 3 metres off the ground, angled slightly down towards the seating area. Higher spreads sound further but sends more of it over the fence.
Can I bury speaker cable in the garden?
Only if it's rated for direct burial. Otherwise run it inside conduit. Either way, keep it away from where you'll dig.
Do I need an electrician to install outdoor speakers?
Not for the speakers. Speaker cable carries a low-voltage audio signal, not mains power. The amp plugs into a normal socket indoors. You only need an electrician if you're adding a new outdoor mains socket.
What size speaker cable do I need for outdoor speakers?
16 AWG (1.5 mm²) for runs up to 15 metres, 14 AWG (2.5 mm²) up to 30 metres, and 12 AWG (4 mm²) beyond that.
Why do my outdoor speakers sound thin?
The most common cause is reversed polarity on one speaker: + and − swapped. The two speakers then partly cancel each other's bass. Check the marked core goes to + at both ends of both cables.