Short answer: the Emotiva Airmotiv B2+. It ranks #72 of 100 bookshelf speakers by sound quality at $449; the KEF Q350 ranks #76 and costs $699, so there is not much of a tradeoff to weigh.
What the Emotiva Airmotiv B2+ offers: Erin measured a useful 86dB average sensitivity and strong midbass punch around 120Hz. Watch for: The replacement B2+ did not deliver the neutral upgrade Erin expected.
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 Emotiva Airmotiv B2+. 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
| Emotiva Airmotiv B2+ | KEF Q350 | |
|---|---|---|
| Price | $449.00 | $699.00 Discontinued |
| Ranked | #72 of 100 in Large Size Bookshelf Speakers | #76 of 100 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 43Hz (measured, Erin’s Audio Corner) | 38Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 66Hz (measured, Erin’s Audio Corner) | 70Hz (measured, Audio Science Review) |
| Sensitivity | 86dB (measured average, Erin’s Audio Corner) | 86dB (measured, Audio Science Review) |
| Drivers | 6.5" woven-fiber woofer, 32 x 25mm folded-ribbon tweeter | 25mm tweeter + 165mm woofer |
| Impedance | 4 ohms nominal (manufacturer specified) | 4 ohms |
| Woofer Cabinet | ported, rear | ported, rear |
| Discontinued | - | Yes |
| Weight | - | 29.5 lbs / 13.4 kg |
| Dimensions | - | 14.1"H x 8.3"W x 12"D (358.0 x 210.0 x 306.0 mm) |
Related Speaker Comparisons
More useful head-to-heads from the same speaker class:
- Polk Monitor XT20 vs JBL XPL-90
- JBL XPL-90 vs Klipsch RP-600M
- Revel Performa M22 vs JBL XPL-90
- SVS Prime Bookshelf vs Emotiva Airmotiv B2+
- KEF Q350 vs Fosi Audio SP601
The Two Speakers In Full
Emotiva Airmotiv B2+: $449.00
Pros: Erin measured a useful 86dB average sensitivity and strong midbass punch around 120Hz. The folded-ribbon tweeter provides very broad upper-treble radiation, and the speaker can create a spacious presentation when positioned carefully. Response and directivity remain reasonably orderly below the roughly 2kHz crossover region. The 6.5-inch woofer offers more output capability than compact 5-inch competitors, while F3/F10 of 66/43Hz leave adequate overlap for a conventional 80Hz subwoofer crossover. Horizontal directivity data makes the broad baffle-step trend amenable to partial EQ below the crossover.
Cons: The replacement B2+ did not deliver the neutral upgrade Erin expected. A baffle-step loss around 500Hz depresses the lower midrange while the AMT’s much wider radiation above crossover injects excess room energy, yielding a bright, forward balance and false impression of cymbal detail. The directivity discontinuity near 2kHz cannot be completely equalized. Erin measured F3 at 66Hz and F10 at 43Hz, so meaningful kick-drum fundamentals and low bass still need a subwoofer. Vertical listening tolerance is roughly +/-10 degrees, with best results between the top of the woofer and tweeter axes. Broad lateral treble energy may require careful toe-out and sidewall absorption. Despite a large cabinet, it offers limited deep-bass advantage and was not Erin’s hoped-for successor to the more linear B1+.
Full Emotiva Airmotiv B2+ review and specifications →
| Bass Extension (-10dB) | 43Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 66Hz (measured, Erin's Audio Corner) |
| Drivers | 6.5" woven-fiber woofer, 32 x 25mm folded-ribbon tweeter |
| Impedance | 4 ohms nominal (manufacturer specified) |
| Sensitivity | 86dB (measured average, Erin's Audio Corner) |
| Woofer Cabinet | ported, rear |
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- Reviews, Comparisons and Sound Samples
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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 |
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