Short answer: the Polk Reserve R100. It ranks #70 of 100 bookshelf speakers by sound quality at $649; the KEF Q350 ranks #76 and costs $699, so there is not much of a tradeoff to weigh.
The case for the Polk Reserve R100: Compact cabinet, unusually useful bass for its size and well-controlled woofer breakup. The tradeoff: Erin measured only about 85dB sensitivity and the impedance reaches 3.6 ohms, so it is neither efficient nor an entirely benign AVR load.
On the KEF Q350 side: CEA2034 spinorama shows a reasonably flat on-axis response with excellent directivity, aided by the coaxial Uni-Q driver. Set against that: Two resonances at 700Hz and 1.2kHz show up on-axis, alongside an upper-bass boost.
Buy the Polk Reserve R100. It ranks higher for sound quality than the KEF Q350 and costs less, so there is no real case for the other one.
If sound quality matters at all to you, skip the KEF Q350. It ranks near the bottom of the 100 bookshelf speakers, so look higher up the list instead.
Specifications Side By Side
| Polk Reserve R100 | KEF Q350 | |
|---|---|---|
| Price | $649/pair | $699.00 Discontinued |
| Ranked | #70 of 100 in Large Size Bookshelf Speakers | #76 of 100 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | 68Hz (measured, Erin’s Audio Corner) | 70Hz (measured, Audio Science Review) |
| Bass Extension (-10dB) | 49Hz (measured, Erin’s Audio Corner) | 38Hz (measured, Audio Science Review) |
| Sensitivity | 85dB/2.83V/1m (measured, Erin’s Audio Corner) | 86dB (measured, Audio Science Review) |
| Impedance | 3.6 ohms minimum (measured, Erin’s Audio Corner) | 4 ohms |
| Drivers | 1" Pinnacle ring-radiator tweeter; 5.25" Turbine Cone midwoofer | 25mm tweeter + 165mm woofer |
| Dimensions | 12.8"H x 6.5"W x 10.2"D | 14.1"H x 8.3"W x 12"D (358.0 x 210.0 x 306.0 mm) |
| Weight | 12.2 lb each | 29.5 lbs / 13.4 kg |
| Woofer Cabinet | ported, rear X-Port | ported, rear |
| Discontinued | - | Yes |
Related Speaker Comparisons
More useful head-to-heads from the same speaker class:
- Revel Performa M22 vs Polk R200
- ELAC DB63 vs Polk R200
- Polk R200 vs Emotiva Airmotiv B2+
- SVS Prime Bookshelf vs Polk Reserve R100
- KEF Q350 vs Wharfedale Diamond 9.1
The Two Speakers In Full
Polk Reserve R100: $649/pair Amazon Polk Audio
Pros: Compact cabinet, unusually useful bass for its size and well-controlled woofer breakup. Erin measured F3/F10 points of 68Hz/49Hz, and the X-Port vent avoids much of the chuffing and pipe resonance common to budget rear ports. The 5.25-inch Turbine Cone woofer and 1-inch Pinnacle ring-radiator tweeter produce good detail at moderate levels, while listening roughly 20° off-axis reduces part of the elevated top octave.
Cons: Erin measured only about 85dB sensitivity and the impedance reaches 3.6 ohms, so it is neither efficient nor an entirely benign AVR load. The treble runs roughly 3dB above the midrange and becomes aggressive above about 85dB SPL. A directivity discontinuity through the woofer/tweeter crossover means EQ cannot fully repair the power response, and a 400Hz impedance feature plus 500Hz-1kHz response irregularity suggests a cabinet or system resonance. Substantial low-frequency compression at higher playback levels limits clean dynamics.
Full Polk Reserve R100 review and specifications →
| Bass Extension (-10dB) | 49Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 68Hz (measured, Erin's Audio Corner) |
| Dimensions | 12.8"H x 6.5"W x 10.2"D |
| Drivers | 1" Pinnacle ring-radiator tweeter; 5.25" Turbine Cone midwoofer |
| Impedance | 3.6 ohms minimum (measured, Erin's Audio Corner) |
| Sensitivity | 85dB/2.83V/1m (measured, Erin's Audio Corner) |
| Weight | 12.2 lb each |
| Woofer Cabinet | ported, rear X-Port |
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- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Polk Reserve R100 vs Polk R200
- Polk Reserve R100 vs JBL XPL-90
- Polk Reserve R100 vs Emotiva Airmotiv B2+
- Polk Reserve R100 vs Revel Performa M22
- Polk Reserve R100 vs Focal Aria 906
- Polk Reserve R100 vs Sonus Faber Lumina II
- Polk Reserve R100 vs Sonus Faber Sonetto II G2
- Polk Reserve R100 vs Polk Monitor XT20
- See all 13 comparisons
KEF Q350: $699.00 Discontinued Amazon
Pros: CEA2034 spinorama shows a reasonably flat on-axis response with excellent directivity, aided by the coaxial Uni-Q driver. Vertical directivity is better than most non-coaxial two-way speakers, another benefit of the concentric design.
Cons: Two resonances at 700Hz and 1.2kHz show up on-axis, alongside an upper-bass boost. Predicted in-room response looks a bit boomy as a result. Distortion climbs substantially in the 100Hz-1kHz range at 96dB SPL/1m, with a distinct resonance-driven peak around 900Hz-1kHz at both test levels. Discontinued.
Full KEF Q350 review and specifications →
| Bass Extension (-10dB) | 38Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | 70Hz (measured, Audio Science Review) |
| Dimensions | 14.1"H x 8.3"W x 12"D (358.0 x 210.0 x 306.0 mm) |
| Discontinued | Yes |
| Drivers | 25mm tweeter + 165mm woofer |
| Impedance | 4 ohms |
| Sensitivity | 86dB (measured, Audio Science Review) |
| Weight | 29.5 lbs / 13.4 kg |
| Woofer Cabinet | ported, rear |
As an eBay Partner, we may be compensated if you make a purchase.
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons