Short answer: the KEF Q150 for better sound quality, the Polk Audio XT15 for the lower price. The KEF Q150 ranks #23 of 63 bookshelf speakers at $350. The Polk Audio XT15 ranks #26 at $179, $171 cheaper.
On the KEF Q150 side: Two-way coaxial (Uni-Q) design with a 1” dome tweeter and 5.25” mid-range time-aligned in a single driver assembly, available in ported or sealed configuration. The catch: A high-frequency lift in the estimated in-room response makes it sound noticeably brighter in an untreated room than in a heavily acoustically-treated one - a real preference factor depending on your room’s furnishings.
The case for the Polk Audio XT15: 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. Watch for: Bass rolls off earlier than most of this batch at 77.6Hz (-3dB) / 54.2Hz (-10dB).
Buy the KEF Q150 if sound quality matters more than the price. Buy the Polk Audio XT15 if the price matters more than sound quality.
Specifications Side By Side
| KEF Q150 | Polk Audio XT15 | |
|---|---|---|
| Price | $350 Discontinued | $179 |
| Ranked | #23 of 63 in Medium Size Bookshelf Speakers | #26 of 63 in Medium Size Bookshelf Speakers |
| Bass Extension (-10dB) | 44Hz (measured, Erin’s Audio Corner) | 54.2Hz (measured, spinorama.org) |
| Bass Extension (-3dB) | 51Hz (measured, Erin’s Audio Corner) | 77.6Hz (measured, spinorama.org) |
| Dimensions | 11.9"H x 7.1"W x 10.9"D (303 x 180 x 278 mm) | 16.51 x 18.24cm (6.5 x 7.18 in), 4.08kg (9 lb) each |
| Impedance | 8 ohms nominal, about 4.7 ohms minimum (measured, Erin’s Audio Corner) | 4/8-ohm compatible |
| Sensitivity | ~85dB (300Hz-3kHz on-axis, measured, Erin’s Audio Corner) | 86dB (1W/1m) |
| Drivers | 130mm (5.25") aluminium Uni-Q woofer, 25mm (1") vented aluminium dome tweeter | 1" Terylene dome tweeter, 5.25" bi-laminate paper woofer |
| Discontinued | Yes | - |
| Weight | 12.3 lbs / 5.6 kg each | 9 lbs / 4.08 kg (9 lb) each |
| Woofer Cabinet | ported, rear | Ported |
Related Speaker Comparisons
More useful head-to-heads from the same speaker class:
- Neumi Silk 4 vs Sony SS-CS5 M2
- Klipsch RP-500M II vs Neumi Silk 4
- Emotiva B1+ vs Neumi Silk 4
- Wharfedale Diamond 220 vs Polk Audio XT15
- Polk Audio XT15 vs JBL Stage 2 250B
The Two Speakers In Full
KEF Q150: $350 Discontinued Amazon
Pros: Two-way coaxial (Uni-Q) design with a 1” dome tweeter and 5.25” mid-range time-aligned in a single driver assembly, available in ported or sealed configuration. Exceptional soundstage depth, a hallmark of KEF’s coaxial designs that the reviewer says few other speakers match. Bass extension reaches into kick-drum territory, respectable for a compact bookshelf speaker. Resonances present in measurements are consistent across on- and off-axis readings, meaning they can be effectively corrected with EQ. Distortion profile is essentially the same whether run sealed or ported, since a subwoofer crossover point sits above where the differences would matter anyway. At its sale price (around $300, sometimes seen at $400), the reviewer considers it a clear step up from his previous budget favorite in this range, the Emotiva B1+, mainly due to the superior soundstage depth.
Cons: A high-frequency lift in the estimated in-room response makes it sound noticeably brighter in an untreated room than in a heavily acoustically-treated one - a real preference factor depending on your room’s furnishings. A mild dip in the 1-2kHz region reduces vocal fullness somewhat. Unexplained resonances appear in measurements and persist in both sealed and ported configurations, pointing to enclosure or panel vibration rather than the port. Horizontal radiation is narrower than the reviewer generally prefers from KEF’s lineup, with directivity that widens somewhat around 1.2kHz (near a resonance) and again above about 5kHz. Compression testing at high output (102dB) shows significant nonlinearity, especially at lower frequencies - noticeably worse than a comparable Arendal bookshelf speaker costing over twice as much, which held up better until 80Hz. Not intended for loud listening without a subwoofer - the woofer will over-exert itself without a high-pass filter, and the reviewer recommends crossing over at 80-120Hz. At full retail price (around $600/pair), the value proposition is far less certain than at sale pricing. Discontinued.
Full KEF Q150 review and specifications →
| Bass Extension (-10dB) | 44Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 51Hz (measured, Erin's Audio Corner) |
| Dimensions | 11.9"H x 7.1"W x 10.9"D (303 x 180 x 278 mm) |
| Discontinued | Yes |
| Drivers | 130mm (5.25") aluminium Uni-Q woofer, 25mm (1") vented aluminium dome tweeter |
| Impedance | 8 ohms nominal, about 4.7 ohms minimum (measured, Erin's Audio Corner) |
| Sensitivity | ~85dB (300Hz-3kHz on-axis, measured, Erin's Audio Corner) |
| Weight | 12.3 lbs / 5.6 kg each |
| Woofer Cabinet | ported, rear |
As an eBay Partner, we may be compensated if you make a purchase.
- Links
- Reviews, Comparisons and Sound Samples
- Erin’s Audio Corner: Kef’s Cheapest Bookshelf. Is the Q150 worth your money?
- Erin’s Audio Corner Website KEF Q150
- GR-Research: KEF Q150… can it get any BETTER?
- Erin’s Audio Corner: 5 AWESOME SPEAKERS Under $1000 You Won’t Regret
- Erin’s Audio Corner: Budget Stereo Systems You Will Love
- Erin’s Audio Corner Measurements (spinorama.org)
- Reddit Search for KEF Q150 Review
- Head-to-Head Comparisons
Polk Audio XT15: $179 Amazon Bhphotovideo Crutchfield
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).
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) |
| Weight | 9 lbs / 4.08 kg (9 lb) each |
| Woofer Cabinet | Ported |
As an eBay Partner, we may be compensated if you make a purchase.
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Polk Audio XT15 vs Neumi Silk 4
- Polk Audio XT15 vs Wharfedale Diamond 220
- Polk Audio XT15 vs JBL Studio 530
- Polk Audio XT15 vs ELAC Debut 2.0 B5.2
- Polk Audio XT15 vs Sony SS-CS5 M2
- Polk Audio XT15 vs Wharfedale Diamond 12.1
- Polk Audio XT15 vs Paradigm Monitor SE Atom
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