Polk Audio Signa S4 vs Sonos Beam Gen 2

The Signa S4 is the most complete home-cinema package here. It is a genuine 3.1.2 layout: three forward channels, two drivers aimed at the ceiling for Atmos height, and a separate wireless subwoofer included rather than sold as an upgrade. Neither Sonos pick includes a sub at all.

VoiceAdjust is the feature that earns its keep daily. It raises the center channel independently of everything else, which is precisely the fix for the modern mixing habit that buries dialogue under score and effects. BassAdjust does the same job at the other end. The bar is slim enough at around 2.36 inches tall not to block the bottom of a television on a stand.

The compromises are structural. Surround effects are virtual, produced by processing rather than by speakers behind you, so they place sound wider rather than actually behind. The slim cabinet limits how loud the bar goes on its own before it hardens, which the subwoofer masks at the bottom and not in the middle. The sub is another box needing floor space and a mains socket. And there is no Wi-Fi, so music from a phone arrives over Bluetooth at Bluetooth quality.

The Beam Gen 2 is the pick for a room that cannot accommodate a separate subwoofer, and it is very good at that job. It is a compact bar with a forward-facing array that produces clear dialogue and more low end than its size suggests, and because it is a Sonos it is also a full streaming speaker: Sonos app, AirPlay 2, voice control, and it joins a multi-room system with any other Sonos speaker.

The correction the marketing does not make is worth stating plainly. There are no up-firing drivers in this bar. It accepts a Dolby Atmos signal and renders height using psychoacoustic processing through the forward array, which produces a taller, wider stage than stereo but does not put sound above you the way a bar with ceiling-aimed drivers does. Against the Polk in this guide, that is the real difference.

The other limits are what you would expect from one small cabinet. Without a subwoofer the bottom octave is simply not there, so explosions have impact rather than weight. It is happiest inside a wider Sonos setup, and adding the sub and rears that unlock its full potential is a substantial further spend. There is no HDMI input, so everything runs through the television.