Short answer: the AsciLab C6B, unless you find a used GR-Research X-LS Encore. The X-LS Encore is described as an amazing value, but its on-axis response shows a slight depression in the upper bass and some peaking in the lower bass. At $1145 versus $1300, the C6B is the cheaper of the two, and its bass still rolls off around 50Hz in-room (F3 54Hz, F10 35Hz).
What the AsciLab C6B gets right: Two-way design pairing a 1” aluminum ceramic dome tweeter on a large waveguide with a 6” aluminum ceramic cone woofer. The catch: Bass rolls off around 50Hz in-room (F3 54Hz, F10 35Hz), so a subwoofer is needed for real extension below that.
On the GR-Research X-LS Encore side: An amazing value, especially if you managed to snag one of these built by AV123 in the early 2000s for $200-300. CEA2034 spinorama shows. The tradeoff: A slight depression in the upper bass and some peaking in the lower bass shows up on-axis.
Buy the AsciLab C6B. It is rated higher for sound quality than the GR-Research X-LS Encore and costs less, which settles it without a real tradeoff to make.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| AsciLab C6B | GR-Research X-LS Encore | |
|---|---|---|
| Price | $1145 per pair | $1300 per pair |
| Ranked | #7 of 130 in Large Size Bookshelf Speakers | #83 of 130 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 35Hz (measured, Erin's Audio Corner) | 44Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 54Hz (measured, Erin's Audio Corner) | 64Hz (measured, Audio Science Review) |
| Dimensions | 15.7"H x 8"W x 10.4"D (398.8 x 203.2 x 264.2 mm) | 13.5"H x 8.5"W x 12.1"D (342.9 x 215.9 x 308 mm) |
| Impedance | 4 ohms nominal, 2.6 ohms minimum (measured, Erin's Audio Corner) | 8 ohms |
| Sensitivity | 85.6dB (measured, Erin's Audio Corner) | 84.4dB (measured by Audio Science Review; 87dB manufacturer specified) |
| Drivers | 6" Aluminium Ceramic Cone with cast Aluminium Chassis woofer, 1" Aluminium Ceramic Dome tweeter | 6.5" Peerless M-165 paper composite cone, non-resonant polymer frame woofer, 1" Peerless India T26SG tweeter |
| Weight | 18.5 lbs (8.4 kg) each | 17 lbs (7.7 kg) each |
| Woofer Cabinet | passive radiator | ported |
| Spinorama Preference Score | 6.33 | 5.05 (measured, spinorama.org) |
| Spinorama Preference Score with Perfect Sub | 8.28 | 7.42 (measured, spinorama.org) |
| DIY Kit | No | Yes |
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Prices on this page were last checked September 23, 2026 at 11:24 PM 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) |
| 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
GR-Research X-LS Encore: $1300 per pair Gr-research eBay
Pros: An amazing value, especially if you managed to snag one of these built by AV123 in the early 2000s for $200-300. CEA2034 spinorama shows a generally flat on-axis response, especially in the listening window. Predicted in-room response is generally smooth and on-target. Distortion at 86dB SPL/1m is pretty clean above 200Hz. Measured bass extension of 64Hz (-3dB), with a measured sensitivity of 84.4dB.
Cons: A slight depression in the upper bass and some peaking in the lower bass shows up on-axis, along with directivity error in the crossover region. Vertical directivity requires staying within about 20 degrees of the tweeter axis. At 96dB SPL/1m distortion becomes “rather unhappy,” with bass distortion, a possible woofer issue around 2kHz, and a tweeter problem above 7kHz. As a DIY kit, it requires building the cabinet and crossover yourself.
Full GR-Research X-LS Encore review and specifications →
| Bass Extension (-10dB) | 44Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | 64Hz (measured, Audio Science Review) |
| DIY Kit | Yes |
| Dimensions | 13.5"H x 8.5"W x 12.1"D (342.9 x 215.9 x 308 mm) |
| Drivers | 6.5" Peerless M-165 paper composite cone, non-resonant polymer frame woofer, 1" Peerless India T26SG tweeter |
| Impedance | 8 ohms |
| Sensitivity | 84.4dB (measured by Audio Science Review; 87dB manufacturer specified) |
| Spinorama Preference Score | 5.05 (measured, spinorama.org) |
| Spinorama Preference Score with Perfect Sub | 7.42 (measured, spinorama.org) |
| Weight | 17 lbs (7.7 kg) each |
| Woofer Cabinet | ported |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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