Short answer: the AsciLab C6B. It ranks #6 of 222 bookshelf speakers by sound quality, rated 4.7/5, at $1,145; the ATC SCM19 ranks #209, rated 2.4/5, and costs $3,750, which makes this an easy call rather than a real tradeoff.
The AsciLab C6B is the more accurate, deeper-bass option. 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 4.61 for the ATC SCM19. Its bass reaches about 54Hz before falling 3dB, against 60Hz for the ATC SCM19. The tradeoff: Bass rolls off around 50Hz in-room (F3 54Hz, F10 35Hz), so a subwoofer is needed for real extension below that.
What the ATC SCM19 does well: Harmonic distortion at 96dB SPL/1m stays generally low across the range aside from the spike tied to the 700-800Hz resonance. The tradeoff: Some stored energy resonance around 500-700Hz, 4dB bump around 700Hz.
Buy the AsciLab C6B. It is rated higher for sound quality than the ATC SCM19 and costs less, so only choose the other one for a particular feature it does better.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| AsciLab C6B | ATC SCM19 | |
|---|---|---|
| Price | $1145 per pair | $3750 per pair |
| Ranked | #6 of 222 in Large Size Bookshelf Speakers | #209 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 35Hz (measured, Erin’s Audio Corner) | 34Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 54Hz (measured, Erin’s Audio Corner) | 60Hz (measured, Audio Science Review) |
| Dimensions | 15.7”H x 8”W x 10.4”D (398.8 x 203.2 x 264.2 mm) | 17.2”H x 10.4”W x 11.8”D (436.9 x 264.2 x 299.7 mm) |
| Impedance | 4 ohms nominal, 2.6 ohms minimum (measured, Erin’s Audio Corner) | 6 ohms |
| Sensitivity | 85.6dB (measured, Erin’s Audio Corner) | 85dB (measured, Audio Science Review) |
| Drivers | 6” Aluminium Ceramic Cone with cast Aluminium Chassis woofer, 1” Aluminium Ceramic Dome tweeter | 5.9” Super Linear Magnet cone woofer, 1” soft dome tweeter |
| Weight | 18.5 lbs (8.4 kg) each | 39.2 lbs (17.8 kg) each |
| Woofer Cabinet | passive radiator | sealed |
| Spinorama Preference Score | 6.33 | 4.61 |
| Spinorama Preference Score with Perfect Sub | 8.28 | 7.03 |
| DIY Kit | No | No |
Frequency Response Compared
Both speakers’ spinorama measurements, overlaid. A flatter line is more neutral: peaks sound forward or harsh, dips sound recessed. Each curve is shifted so its average from 300 Hz to 3 kHz sits at 0 dB, so loudness differences between the two are removed and only the shape is compared. The two were measured by different sources, so small differences, especially in the bass, can come from the measurement setup rather than the speakers.
Measurement data: AsciLab C6B (measured by Erin’s Audio Corner) and ATC SCM19 (measured by Audio Science Review), via spinorama.org.
Related Speaker Comparisons
More worthwhile head-to-heads for AsciLab C6B:
- AsciLab C6B vs Perlisten S4b
- AsciLab C6B vs KEF Reference 1 Meta
- AsciLab C6B vs GR-Research NX-Studio
- AsciLab C6B vs March Audio Sointuva AWG
- AsciLab C6B vs Audio First Cadentia 3
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The Two Speakers In Full
AsciLab C6B: $1145 per pair Ascilab $1145 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
ATC SCM19: $3750 per pair The Music Room $3750 eBay
Same family: the ATC SCM40 (floorstanding, estimated 2.6/5).
Pros: Harmonic distortion at 96dB SPL/1m stays generally low across the range aside from the spike tied to the 700-800Hz resonance. Sealed (unported) cabinet avoids port noise and resonance, and the extremely dense, heavy-duty enclosure (17.8kg/39lb each) reflects ATC’s pro-audio build standards. Measured bass extension of 60Hz (-3dB), with a measured sensitivity of 85dB.
Cons: Some stored energy resonance around 500-700Hz, 4dB bump around 700Hz. Not recommended for the price. CEA2034 spinorama and predicted in-room response both show a very uneven overall balance (a broad accentuation from midrange to treble paired with too little bass) along with directivity error. At 96dB SPL/1m, harmonic distortion tied to the 500-700Hz resonance rises to a level the reviewer says “should not be there.”
Full ATC SCM19 review and specifications →
| Released | 2013 (13 years ago) |
|---|---|
| Bass Extension (-10dB) | 34Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 60Hz (measured, Audio Science Review) |
| DIY Kit | No |
| Dimensions | 17.2”H x 10.4”W x 11.8”D (436.9 x 264.2 x 299.7 mm) |
| Drivers | 5.9” Super Linear Magnet cone woofer, 1” soft dome tweeter |
| Impedance | 6 ohms |
| Sensitivity | 85dB (measured, Audio Science Review) |
| Spinorama Preference Score | 4.61 |
| Spinorama Preference Score with Perfect Sub | 7.03 |
| Weight | 39.2 lbs (17.8 kg) each |
| Woofer Cabinet | sealed |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons