Short answer: the Radiant Acoustics Clarity 4.2 for better sound quality, the Polk Audio XT15 for the lower price. The Radiant Acoustics Clarity 4.2 ranks #23 of 87 bookshelf speakers at $2998. The Polk Audio XT15 ranks #29 at $159.99, $2838.01 cheaper.
What the Polk Audio XT15 offers: 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. Directivity spread is reasonably even for the price (directivity_spdi_stddev 3.60). Watch for: Bass rolls off earlier than most of this batch at 77.6Hz (-3dB) / 54.2Hz (-10dB). On-axis deviation is the roughest measured figure here (aad_on_axis 0.449), and listening-window smoothness (0.303) trails the pricier options in this group. 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.
What the Radiant Acoustics Clarity 4.2 offers: Compact bookshelf design using a 4” Purifi mid-woofer with matching Purifi passive radiators and an AMT tweeter on a purpose-designed waveguide, built with genuine heft - aluminum baffle, extensive internal bracing and damping. Surprisingly wide horizontal dispersion (about ±70° through the midrange and into the treble), more enveloping than its larger 6.2 sibling despite the smaller cabinet. More linear on-axis than the bigger Clarity 6.2, which needs 15-20° of toe-out to tame a rising treble; the 4.2 can be listened to closer to on-axis without that same correction. Wider-than-typical vertical dispersion (roughly +30°/-20°) for a two-way design, since its smaller woofer keeps the tweeter-to-woofer distance short. Genuinely deep bass extension for its size (F3 44Hz, reaching about 40Hz in-room), though it comes at a real cost to sensitivity. No resonance issues visible in impedance measurements. Watch for: Low sensitivity (rated 78dB, measured 78.5dB) is the trade-off for its bass extension - needs a fair amount of amplifier power, around 100W recommended for small-to-medium rooms versus the manufacturer’s own 60W baseline. Designed specifically for smaller rooms; the reviewer had to move testing out of his open-plan living room and into a smaller bedroom to avoid running into compression. A dip in the upper midrange gives a mild lack of attack and clarity, and a peak around 5kHz occasionally added a touch of extra sibilance. Multitone distortion crosses the reviewer’s 3% threshold at 96dB, making about 88dB a better average listening level; a slight upper-midrange bump persists even with an 80Hz high-pass filter applied. Dynamic range is limited: fine at 86dB, but the woofer starts giving up headroom by 96dB and drops off significantly by 102dB. Compared to its pricier sibling Clarity 6.2, has notably less dynamic range and higher multitone distortion, reflecting the smaller driver complement. A niche product size-wise - the reviewer couldn’t identify a clear direct competitor in the same size/price/SPL class.
Buy the Polk Audio XT15 when the price outweighs sound quality for you, and the Radiant Acoustics Clarity 4.2 when sound quality outweighs the price instead.
Looking for alternatives? See the complete Passive Home rankings.
Specifications Side By Side
| Polk Audio XT15 | Radiant Acoustics Clarity 4.2 | |
|---|---|---|
| Price | $159.99 per pair | $2,998 per pair |
| Ranked | #29 of 87 in Medium Size Bookshelf Speakers | #23 of 87 in Medium Size Bookshelf Speakers |
| Bass Extension (-10dB) | 54.2Hz (measured, spinorama.org) | 35 Hz (measured, Erin's Audio Corner) |
| Bass Extension (-3dB) | 77.6Hz (measured, spinorama.org) | 44 Hz (measured, Erin's Audio Corner) |
| Dimensions | 16.51 x 18.24cm (6.5 x 7.18 in), 4.08kg (9 lb) each | 9.5"H x 6.3"W x 9.4"D (241 x 160 x 239 mm) |
| Impedance | 4/8-ohm compatible | 4 ohms |
| Sensitivity | 86dB (1W/1m) | 78 dB |
| Drivers | 1" Terylene dome tweeter, 5.25" bi-laminate paper woofer | (2) 4" (102mm) woofer + AMT tweeter |
| Weight | 9 lbs (4.08 kg) each | 28.7 lbs (13 kg) (per pair: 57.3 lbs (26 kg)) |
| Woofer Cabinet | Ported | passive radiator |
| Spinorama Preference Score | 3.65 | - |
| Spinorama Preference Score with Perfect Sub | 6.40 | - |
| Frequency Response | - | 40 Hz - 25 kHz |
| Recommended Power | - | 50-200W |
| Amplifier Power | - | External amplifier required |
Related Speaker Comparisons
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- Audio First Fidelia vs Radiant Acoustics Clarity 4.2
- Ascend Sierra 1 v2 vs Radiant Acoustics Clarity 4.2
- KEF LS50 Meta vs Radiant Acoustics Clarity 4.2
- Arendal 1961 Monitor vs Radiant Acoustics Clarity 4.2
- Moondrop M4P MTM vs Radiant Acoustics Clarity 4.2
Prices on this page were last checked September 16, 2026 at 12:41 AM 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: $159.99 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. Directivity spread is reasonably even for the price (directivity_spdi_stddev 3.60). Measured bass extension of 77.6Hz (-3dB).
Cons: Bass rolls off earlier than most of this batch at 77.6Hz (-3dB) / 54.2Hz (-10dB). On-axis deviation is the roughest measured figure here (aad_on_axis 0.449), and listening-window smoothness (0.303) trails the pricier options in this group. 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) |
| 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 | 3.65 |
| Spinorama Preference Score with Perfect Sub | 6.40 |
| Weight | 9 lbs (4.08 kg) each |
| Woofer Cabinet | Ported |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Polk Audio XT15 vs Wharfedale Diamond 220
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Radiant Acoustics Clarity 4.2: $2,998 per pair Radiant Acoustics eBay
Pros: Compact bookshelf design using a 4” Purifi mid-woofer with matching Purifi passive radiators and an AMT tweeter on a purpose-designed waveguide, built with genuine heft - aluminum baffle, extensive internal bracing and damping. Surprisingly wide horizontal dispersion (about ±70° through the midrange and into the treble), more enveloping than its larger 6.2 sibling despite the smaller cabinet. More linear on-axis than the bigger Clarity 6.2, which needs 15-20° of toe-out to tame a rising treble; the 4.2 can be listened to closer to on-axis without that same correction. Wider-than-typical vertical dispersion (roughly +30°/-20°) for a two-way design, since its smaller woofer keeps the tweeter-to-woofer distance short. Genuinely deep bass extension for its size (F3 44Hz, reaching about 40Hz in-room), though it comes at a real cost to sensitivity. No resonance issues visible in impedance measurements. Measured bass extension of 44 Hz (-3dB).
Cons: Low sensitivity (rated 78dB, measured 78.5dB) is the trade-off for its bass extension - needs a fair amount of amplifier power, around 100W recommended for small-to-medium rooms versus the manufacturer’s own 60W baseline. Designed specifically for smaller rooms; the reviewer had to move testing out of his open-plan living room and into a smaller bedroom to avoid running into compression. A dip in the upper midrange gives a mild lack of attack and clarity, and a peak around 5kHz occasionally added a touch of extra sibilance. Multitone distortion crosses the reviewer’s 3% threshold at 96dB, making about 88dB a better average listening level; a slight upper-midrange bump persists even with an 80Hz high-pass filter applied. Dynamic range is limited: fine at 86dB, but the woofer starts giving up headroom by 96dB and drops off significantly by 102dB. Compared to its pricier sibling Clarity 6.2, has notably less dynamic range and higher multitone distortion, reflecting the smaller driver complement. A niche product size-wise - the reviewer couldn’t identify a clear direct competitor in the same size/price/SPL class.
Full Radiant Acoustics Clarity 4.2 review and specifications →
| Amplifier Power | External amplifier required |
|---|---|
| Bass Extension (-10dB) | 35 Hz (measured, Erin's Audio Corner) |
| Bass Extension (-3dB) | 44 Hz (measured, Erin's Audio Corner) |
| Dimensions | 9.5"H x 6.3"W x 9.4"D (241 x 160 x 239 mm) |
| Drivers | (2) 4" (102mm) woofer + AMT tweeter |
| Frequency Response | 40 Hz - 25 kHz |
| Impedance | 4 ohms |
| Recommended Power | 50-200W |
| Sensitivity | 78 dB |
| Weight | 28.7 lbs (13 kg) (per pair: 57.3 lbs (26 kg)) |
| Woofer Cabinet | passive radiator |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Radiant Acoustics Clarity 4.2 vs Wharfedale Diamond 12.1
- Radiant Acoustics Clarity 4.2 vs KEF Q150
- Radiant Acoustics Clarity 4.2 vs Wharfedale Super Denton
- Radiant Acoustics Clarity 4.2 vs Klipsch RP-500M II
- Radiant Acoustics Clarity 4.2 vs Moondrop M4P MTM
- Radiant Acoustics Clarity 4.2 vs Arendal 1961 Monitor
- Radiant Acoustics Clarity 4.2 vs KEF LS50 Meta
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- See all 23 comparisons