Head-to-head · Best Soundbars Under $300

Polk Audio Signa S2 vs VIZIO M-Series 5.1 (M51ax-J6)

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

The short answer

Polk Audio Signa S2 and VIZIO M-Series 5.1 (M51ax-J6) score essentially the same (4.3 vs 4.3). Pick the one whose trade-offs match your priorities — the strengths and watch-outs below are where they actually differ.

Ranked #5 in Best Soundbars Under $300

Polk Audio Signa S2

4.3

$200

The Signa S2 is the budget tier of this round-up. Polk's VoiceAdjust delivers dialog clarity comparable to the Signa S4 at a third the price, and the wireless 5.25" sub gives it real low-end despite the 2.1 layout. The compromises are predictable: no Atmos, older HDMI ARC, Bluetooth-only streaming. For a first soundbar upgrading from TV speakers, this is the entry point.

Strengths

— Cheapest pick in this round-up — frequently under $200
— Wireless 5.25" subwoofer included
— Polk's VoiceAdjust technology for dialog clarity

Watch-outs

— No Dolby Atmos support (virtual or real) — 2.1 only
— Older HDMI ARC (not eARC) — limits high-bitrate audio passthrough
— Bluetooth only — no Wi-Fi or streaming app integration

$200 · Check Price on Amazon Full review →

Ranked #3 in Best Soundbars Under $300

VIZIO M-Series 5.1 (M51ax-J6)

4.3

$270

The M-Series 5.1 is the value crossover — full 5.1 channel layout plus virtualized Dolby Atmos/DTS:X at the lowest price among true 5.1 systems here. Vizio packed 9 drivers into the bar and includes a wireless subwoofer. The trade-off vs Polk Audio Signa S4 is that Vizio simulates height channels rather than driving them with upfiring speakers — fine for most movies, audibly weaker on aggressive Atmos mixes. Best buy when on sale below $250.

Strengths

— 5.1 channel layout with wireless subwoofer included
— Dolby Atmos and DTS:X support via virtualization
— 9-driver array with separate tweeters and woofers

Watch-outs

— Virtualized (not native) Atmos — height effects are simulated, not real
— 5" subwoofer is smaller than the Samsung HW-B750D's larger driver
— Vizio's software ecosystem (SmartCast) lags Samsung and Polk in features

$270 · Check Price on Amazon Full review →

How they stack up

Polk Audio Signa S2

Cheapest pick by a wide margin. No Atmos (real or virtual) — Samsung HW-B750D simulates with DTS Virtual:X, Vizio M-Series 5.1 and Yamaha SR-B40A virtualize Atmos, and Polk Audio Signa S4 has real upfiring. Same VoiceAdjust dialog tech as the Signa S4 at a third the price.

VIZIO M-Series 5.1 (M51ax-J6)

Matches the Samsung HW-B750D on 5.1 channel count at a lower price. Loses to the Polk Audio Signa S4 on real (vs virtualized) Atmos. Beats the Yamaha SR-B40A and Polk Audio Signa S2 on channel count, which are 2.1 configurations.

Specs side-by-side

Spec	Polk Audio Signa S2	VIZIO M-Series 5.1 (M51ax-J6)
Channels	2.1	5.1
Subwoofer	Wireless 5.25" included	Wireless 5" included
Audio Formats	Dolby Digital 5.1 (downmixed)	Dolby Atmos (virtual), DTS:X (virtual)
Connectivity	HDMI ARC, Optical, Bluetooth	HDMI eARC, Optical, Bluetooth
Dialog Tech	VoiceAdjust	—
Drivers	—	9-driver array

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