Short answer: the Polk Audio XT15. It ranks #29 of 92 bookshelf speakers by sound quality, rated 3.7/5, at $179; the Sony SS-CS5 M2 ranks #50, rated 3.2/5, and costs $278, so there is little reason to consider the other one.
Buy the Polk Audio XT15. It is rated higher for sound quality than the Sony SS-CS5 M2 and costs less, so only choose the other one for a particular feature it does better.
Looking for alternatives? See the complete Passive Home rankings.
Specifications Side By Side
| Polk Audio XT15 | Sony SS-CS5 M2 | |
|---|---|---|
| Price | $179.00 per pair | $278.00 per pair |
| Ranked | #29 of 92 in Medium Size Bookshelf Speakers | #50 of 92 in Medium Size Bookshelf Speakers |
| Bass Extension (-10dB) | 54.2Hz (measured, spinorama.org) | 54Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 77.6Hz (measured, spinorama.org) | 80Hz (measured, Erin’s Audio Corner) |
| Dimensions | 16.51 x 18.24cm (6.5 x 7.18 in), 4.08kg (9 lb) each | 13.2”H x 7”W x 8.7”D (335 x 178 x 220 mm) |
| Impedance | 4/8-ohm compatible | 6 ohms |
| Sensitivity | 86dB (1W/1m) | 82.5dB |
| Drivers | 1” Terylene dome tweeter, 5.25” bi-laminate paper woofer | 5.12” woofer, 0.98 in tweeter; 0.75-inch supertweeter; 0.75-inch supertweeter; 0.75-inch supertweeter; 0.75-inch supertweeter |
| Weight | 9 lbs (4.08 kg) each | 9.5 lbs (4.3 kg) each |
| Woofer Cabinet | Ported | ported, rear |
| Spinorama Preference Score | 4.56 | - |
| Spinorama Preference Score with Perfect Sub | 7.31 | - |
| DIY Kit | No | No |
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Prices on this page were last checked October 3, 2026 at 10:26 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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The Two Speakers In Full
Polk Audio XT15: $179.00 per pair Amazon B&H Photo Video Crutchfield eBay
Pros: Very low $179/pair entry price for a Hi-Res Audio Certified 2-way design that’s Dolby Atmos and DTS:X compatible, and works with either 4- or 8-ohm amplifier outputs so it drops into almost any AVR without matching concerns. Off axis sound tracks the on axis response reasonably consistently for the price. Measured bass extension of 77.6Hz (-3dB).
Cons: Bass rolls off early, at 77.6Hz (-3dB) and 54.2Hz (-10dB). On-axis response is relatively uneven, with an average deviation of about 0.45dB, and its listening window is less smooth than pricier speakers. Modest 86dB sensitivity wants a reasonably powered amp channel. The 5.25” bi-laminate paper woofer is Polk’s entry-tier driver, not the polypropylene/Turbine cones used in its pricier Signature Elite/Reserve lines.
Full Polk Audio XT15 review and specifications →
| Bass Extension (-10dB) | 54.2Hz (measured, spinorama.org) |
|---|---|
| Bass Extension (-3dB) | 77.6Hz (measured, spinorama.org) |
| DIY Kit | No |
| Dimensions | 16.51 x 18.24cm (6.5 x 7.18 in), 4.08kg (9 lb) each |
| Drivers | 1” Terylene dome tweeter, 5.25” bi-laminate paper woofer |
| Impedance | 4/8-ohm compatible |
| Sensitivity | 86dB (1W/1m) |
| Spinorama Preference Score | 4.56 |
| Spinorama Preference Score with Perfect Sub | 7.31 |
| Weight | 9 lbs (4.08 kg) each |
| Woofer Cabinet | Ported |
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Sony SS-CS5 M2: $278.00 per pair Amazon eBay
Pros: Added internal bracing (corners, sides, front baffle) plus an updated crossover meaningfully reduce the resonance issues that plagued the original SS-CS5, giving a smoother, more neutral character overall. A modest mid-range dip (about 1-2dB) is present but tolerable, and the reviewer would rather have this dip than a peak in that region. Slightly deeper bass than the previous version, measuring about 2dB more output around 60Hz. Distortion drops noticeably when crossed to a subwoofer around 80-120Hz, meaningfully improving midrange clarity and detail versus running full-range. Easy to drive on a standard AVR: no need for a dedicated high-power amplifier. More modern, understated waveguide look compared to the previous version’s glossy trim. Measured bass extension of 80Hz (-3dB).
Cons: Mild sibilance in the 3-5kHz range stands out on S and T sounds in vocals. Some forwardness in the midrange noticeable on certain vocal recordings. Soundstage and sense of envelopment are comparatively flat and two-dimensional, especially next to reference-quality speakers with strong 3D imaging. Marketed as a “three-way” design mainly due to an added super-tweeter that the reviewer considers largely superfluous: it engages only at very high frequencies and adds complexity without a clearly audible benefit, when that cost might have been better spent on the main crossover. Output-limited: realistic ceiling is around the mid-90s dB SPL at a few meters, with comfortable listening closer to 75-85dB at 3-4 meters before distortion and compression become audible. Bass noticeably compresses/shelves below about 120Hz as volume increases, softening kick-drum impact at higher output. Smaller drivers and a lighter motor structure than rivals like the Polk XT20, which the reviewer generally prefers for its better directivity and higher SPL capability. Still needs a subwoofer for any real bass extension.
Full Sony SS-CS5 M2 review and specifications →
| Bass Extension (-10dB) | 54Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 80Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 13.2”H x 7”W x 8.7”D (335 x 178 x 220 mm) |
| Drivers | 5.12” woofer, 0.98 in tweeter; 0.75-inch supertweeter; 0.75-inch supertweeter; 0.75-inch supertweeter; 0.75-inch supertweeter |
| Impedance | 6 ohms |
| Sensitivity | 82.5dB |
| Weight | 9.5 lbs (4.3 kg) each |
| Woofer Cabinet | ported, rear |
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