Short answer: the AsciLab C6B if sound quality matters most, the XTZ Spirit 4 if price matters most. The AsciLab C6B ranks #7 of 130 bookshelf speakers at $1145. The XTZ Spirit 4 ranks #92 at $477, $668 cheaper.
What the AsciLab C6B offers: 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 $935 (about $1,135 shipped to the US), the reviewer calls it the best-value bookshelf speaker he’s tested, rivaling speakers 2-5x the price. Watch for: 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 the $935 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.
What the XTZ Spirit 4 offers: Substantial 6.5-inch stand-mount with a waveguided dome tweeter, adjustable treble level and port tuning. Spinorama predicts 44Hz in-room extension, broad roughly +/-60-degree horizontal coverage and a 5.39 preference score with a subwoofer. Watch for: The third-party measurement is low confidence. On-axis smoothness is only 0.248, directivity-index consistency is middling at 3.21, and the mildly downward -0.29dB/octave tonal slope contributes to a modest 3.27 raw preference score.
Buy the AsciLab C6B if sound quality matters more than the price. Buy the XTZ Spirit 4 if the price matters more than sound quality.
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Specifications Side By Side
| AsciLab C6B | XTZ Spirit 4 | |
|---|---|---|
| Price | $1145 per pair | $477 per pair |
| Ranked | #7 of 130 in Large Size Bookshelf Speakers | #92 of 130 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 35Hz (measured, Erin's Audio Corner) | - |
| Bass Extension (-3dB) | 54Hz (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) | 13.8H x 7.5W x 10.6D in |
| Impedance | 4 ohms nominal, 2.6 ohms minimum (measured, Erin's Audio Corner) | 4 ohms |
| Sensitivity | 85.6dB (measured, Erin's Audio Corner) | 86dB |
| Drivers | 6" Aluminium Ceramic Cone with cast Aluminium Chassis woofer, 1" Aluminium Ceramic Dome tweeter | 1" dome tweeter, 6.5" woofer |
| Weight | 18.5 lbs (8.4 kg) each | 17.9 lbs (8.1 kg) each |
| Woofer Cabinet | passive radiator | - |
| Spinorama Preference Score | 5.66 | 3.27 |
| Spinorama Preference Score with Perfect Sub | 7.60 | 5.39 |
| Enclosure | - | 2-way passive, rear-ported |
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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
AsciLab C6B: $1145 per pair Ascilab eBay
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 $935 (about $1,135 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 the $935 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) |
| 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 | 5.66 |
| Spinorama Preference Score with Perfect Sub | 7.60 |
| Weight | 18.5 lbs (8.4 kg) each |
| Woofer Cabinet | passive radiator |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
XTZ Spirit 4: $477 per pair XTZ eBay
Pros: Substantial 6.5-inch stand-mount with a waveguided dome tweeter, adjustable treble level and port tuning. Spinorama predicts 44Hz in-room extension, broad roughly +/-60-degree horizontal coverage and a 5.39 preference score with a subwoofer.
Cons: The third-party measurement is low confidence. On-axis smoothness is only 0.248, directivity-index consistency is middling at 3.21, and the mildly downward -0.29dB/octave tonal slope contributes to a modest 3.27 raw preference score.
Full XTZ Spirit 4 review and specifications →
| Dimensions | 13.8H x 7.5W x 10.6D in |
|---|---|
| Drivers | 1" dome tweeter, 6.5" woofer |
| Enclosure | 2-way passive, rear-ported |
| Impedance | 4 ohms |
| Sensitivity | 86dB |
| Spinorama Preference Score | 3.27 |
| Spinorama Preference Score with Perfect Sub | 5.39 |
| Weight | 17.9 lbs (8.1 kg) each |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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