Short answer: the AsciLab C6B. It ranks #6 of 203 bookshelf speakers by sound quality (rated 4.7/5) at $1,145 and is still sold new; the Emotiva Airmotiv B2+ ranks #169 (rated 3.0/5) and is discontinued, so it is only an option used. The Emotiva Airmotiv B2+’s replacement, the Emotiva Airmotiv XB2, is rated 4.2/5.
The AsciLab C6B is the more accurate, deeper-bass choice. Two-way design pairing a 1” aluminum ceramic dome tweeter on a large waveguide with a 6” aluminum ceramic cone woofer, crossed over at 1.1kHz, plus a rear passive radiator. Its measured preference score, a predictor of how neutral it sounds, is 6.33 against 5.60 for the Emotiva Airmotiv B2+. Its bass reaches about 54Hz before falling 3dB, against 66Hz for the Emotiva Airmotiv B2+. Watch for: Bass rolls off around 50Hz in-room (F3 54Hz, F10 35Hz), so a subwoofer is needed for real extension below that.
Why pick the Emotiva Airmotiv B2+: Erin measured a useful 86dB average sensitivity and strong midbass punch around 120Hz. The catch: The replacement B2+ did not deliver the neutral upgrade Erin expected.
Buy the AsciLab C6B. It is rated higher for sound quality and still sold new, while the Emotiva Airmotiv B2+ is discontinued.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| AsciLab C6B | Emotiva Airmotiv B2+ | |
|---|---|---|
| Price | $1145 per pair | $449 per pair Discontinued |
| Ranked | #6 of 203 in Large Size Bookshelf Speakers | #169 of 203 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 35Hz (measured, Erin’s Audio Corner) | 43Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 54Hz (measured, Erin’s Audio Corner) | 66Hz (measured, Erin’s Audio Corner) |
| Dimensions | 15.7”H x 8”W x 10.4”D (398.8 x 203.2 x 264.2 mm) | 12.8”H x 8.5”W x 11.5”D (324 x 216 x 293 mm) |
| Impedance | 4 ohms nominal, 2.6 ohms minimum (measured, Erin’s Audio Corner) | 4 ohms nominal (manufacturer specified) |
| Sensitivity | 85.6dB (measured, Erin’s Audio Corner) | 86dB (measured average, Erin’s Audio Corner) |
| Drivers | 6” Aluminium Ceramic Cone with cast Aluminium Chassis woofer, 1” Aluminium Ceramic Dome tweeter | 6.5” woven-fiber woofer, 32 x 25mm folded-ribbon tweeter |
| Weight | 18.5 lbs (8.4 kg) each | 15.7 lbs (7.1 kg) each |
| Woofer Cabinet | passive radiator | ported, rear |
| Spinorama Preference Score | 6.33 | 5.60 |
| Spinorama Preference Score with Perfect Sub | 8.28 | 7.96 |
| DIY Kit | No | No |
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The Two Speakers In Full
AsciLab C6B: $1145 per pair Ascilab eBay
Same family: the AsciLab C5B (smaller bookshelf, rated 4.2/5).
Pros: Two-way design pairing a 1” aluminum ceramic dome tweeter on a large waveguide with a 6” aluminum ceramic cone woofer, crossed over at 1.1kHz, plus a rear passive radiator. Unusual trait: horizontal radiation actually widens at higher frequencies instead of narrowing like most two-way designs, which keeps image focus and soundstage depth consistent whether you toe the speakers in or out (5-10° off-axis was the sweet spot in testing). Vertical radiation also stays wide straight through the 2kHz crossover region, so the sound doesn’t collapse when standing up: unusual at this price. CA2034 measurements show strong on-axis linearity, listening window, early reflections, and directivity. Midrange and tweeter distortion stay very low even at 96dB, holding up against a $5,900 Arendal speaker in that regard despite roughly a 5x price gap. At $1145 shipped to the US, the reviewer calls it the best-value bookshelf speaker he’s tested, rivaling speakers 2-5x the price. Measured bass extension of 54Hz (-3dB), with a measured sensitivity of 85.6dB.
Cons: Bass rolls off around 50Hz in-room (F3 54Hz, F10 35Hz), so a subwoofer is needed for real extension below that. Low-frequency harmonic distortion increases substantially at 96dB versus 86dB, though it’s second-order and less audible than it looks on paper. Minimum impedance dips to 2.6 ohms (EPDR as low as 1.2 ohms), so it wants an amplifier comfortable driving 4-ohm loads, ideally 100W or more. At 102dB, compression noticeably eats into midrange, bass, and some treble output. Shipping to the US adds roughly $200 on top of AsciLab’s list price. Against the reviewer’s reference Audiofirst Fidelia at a similar price, has slightly less lower-midrange body (about 1dB difference) and a smaller perceived soundstage size.
Full AsciLab C6B review and specifications →
| Bass Extension (-10dB) | 35Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 54Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 15.7”H x 8”W x 10.4”D (398.8 x 203.2 x 264.2 mm) |
| Drivers | 6” Aluminium Ceramic Cone with cast Aluminium Chassis woofer, 1” Aluminium Ceramic Dome tweeter |
| Impedance | 4 ohms nominal, 2.6 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 85.6dB (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 6.33 |
| Spinorama Preference Score with Perfect Sub | 8.28 |
| Weight | 18.5 lbs (8.4 kg) each |
| Woofer Cabinet | passive radiator |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Emotiva Airmotiv B2+: $449 per pair Discontinued eBay
Newer model: the Emotiva Airmotiv XB2, ranked higher, rated 4.2/5.
Same family: the Emotiva Airmotiv T2+ (floorstanding, rated 4.2/5) and the Emotiva Airmotiv C2+ (center, rated 2.9/5).
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. Measured bass extension of 66Hz (-3dB), with a measured sensitivity of 86dB.
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+. Discontinued.
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) |
| DIY Kit | No |
| Dimensions | 12.8”H x 8.5”W x 11.5”D (324 x 216 x 293 mm) |
| 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) |
| Spinorama Preference Score | 5.60 |
| Spinorama Preference Score with Perfect Sub | 7.96 |
| Weight | 15.7 lbs (7.1 kg) each |
| Woofer Cabinet | ported, rear |
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