Polk Atrium 6 vs Atrium 4
Short answer: get the Atrium 6 for an average garden, or anywhere you'll sit more than a few metres from the speakers. Get the Atrium 4 for a patio, balcony or covered seating area, or where a smaller speaker fits better.
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The two speakers
Specs side by side
| Atrium 6 | Atrium 4 | |
|---|---|---|
| Woofer | 5.25" | 4.5" |
| Tweeter | 1" aluminium | 0.75" aluminium |
| Frequency response | 50 Hz – 27 kHz | 75 Hz – 25 kHz |
| Sensitivity | 90 dB | 89 dB |
| Impedance | 8 Ω | 8 Ω |
| Recommended amp | 10–100 W | 10–80 W |
| Size (H × W × D) | 29.7 × 19.5 × 22.2 cm | 21.9 × 14.5 × 17.0 cm |
From Polk's published specifications as listed by authorised retailers.
What's actually different
Bass is the big one. The Atrium 6 reaches down to 50 Hz; the Atrium 4 stops at 75 Hz. That's the difference between hearing the bass line properly and hearing it as a thinner outline, and it matters more outside, where there are no walls to reinforce low notes.
Size. The Atrium 4 is about a third smaller in every direction. Under a low eave, on a balcony or next to a door frame, that can decide it.
Power. The Atrium 6 handles up to 100 W per channel against 80 W, so it stays clean at higher volume. Their sensitivity is almost the same (90 vs 89 dB), so both get loud from a small amp.
What they share. Both are passive, 8-ohm, all-weather certified by Polk, mount on included brackets, and come in black or white.
Buy the Atrium 6 if…
- You're covering an average garden or a deck
- You'll sit more than 3 to 4 metres from the speakers
- You want fuller bass without adding a subwoofer
- You'll sometimes turn it up for guests
Buy the Atrium 4 if…
- You're covering a patio, balcony or covered seating area
- You'll sit close to the speakers
- Space under the eave is tight
- You want to keep the cost down
Need more than either?
For a long garden, a pool area or parties, look at the Klipsch AW-650: at 95 dB it plays noticeably louder from the same amp. If your home already uses Sonos, see Sonos Outdoor. Both are in our main guide.
FAQ
Is the Polk Atrium 6 better than the Atrium 4?
For most gardens, yes. Its bigger 5.25-inch woofer reaches down to 50 Hz against the Atrium 4's 75 Hz, so it sounds fuller, and it handles more power. The Atrium 4 is smaller and cheaper, and is enough for a patio or balcony.
Do the Polk Atrium speakers need an amplifier?
Yes. Both are passive speakers. Any amp that delivers 10 to 80 W (Atrium 4) or 10 to 100 W (Atrium 6) per channel into 8 ohms will drive them. A small Bluetooth amp like the Fosi Audio BT20A lets you play from your phone.
Are Polk Atrium speakers sold as a pair?
The Atrium 4 and Atrium 6 are usually sold as pairs. Check the listing before you buy.
Can Polk Atrium speakers stay outside in winter?
Yes. Both carry Polk's all-weather certification and use rust-resistant hardware. Mounting them under an eave helps them last longer.