Short answer: the AsciLab C6B. It ranks #6 of 214 bookshelf speakers by sound quality (rated 4.7/5) at $1,145 and is still sold new; the Klipsch RP-600M ranks #185 (rated 2.9/5) and is discontinued, so it is only an option used. The Klipsch RP-600M’s replacement, the Klipsch RP-600M II, is rated 3.7/5.
Why pick the Klipsch RP-600M: More linear horizontal dispersion than the updated Klipsch RP-600M II: as you move side-to-side, the tonal character changes less, a genuine advantage for off-axis listening consistency. Watch for: A strong, annoying resonance in the lower vocal range around 300Hz stands out clearly (though it can be EQ’d out).
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 3.66 for the Klipsch RP-600M. Its bass reaches about 54Hz before falling 3dB, against 73Hz for the Klipsch RP-600M. The tradeoff: Bass rolls off around 50Hz in-room (F3 54Hz, F10 35Hz), so a subwoofer is needed for real extension below that.
Buy the AsciLab C6B. It is rated higher for sound quality; the Klipsch RP-600M is no longer sold new.
Looking for alternatives? See the complete Passive Home rankings.
Specifications Side By Side
| Klipsch RP-600M | AsciLab C6B | |
|---|---|---|
| Price | $239.97 per pair Discontinued | $1145 per pair |
| Ranked | #185 of 214 in Large Size Bookshelf Speakers | #6 of 214 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 40Hz (measured, Erin’s Audio Corner) | 35Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 73Hz (measured, Erin’s Audio Corner) | 54Hz (measured, Erin’s Audio Corner) |
| Dimensions | 15.7”H x 8”W x 11.9”D (398.8 x 203.2 x 302.3 mm) | 15.7”H x 8”W x 10.4”D (398.8 x 203.2 x 264.2 mm) |
| Impedance | 8 ohms nominal, 3.5 ohms minimum (measured, Erin’s Audio Corner) | 4 ohms nominal, 2.6 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 85.2dB (measured, Erin’s Audio Corner) | 85.6dB (measured, Erin’s Audio Corner) |
| Drivers | 6.5” Cerametallic cone woofer, 1” titanium LTS vented tweeter with Tractrix horn | 6” Aluminium Ceramic Cone with cast Aluminium Chassis woofer, 1” Aluminium Ceramic Dome tweeter |
| Weight | 16.1 lbs (7.3 kg) each | 18.5 lbs (8.4 kg) each |
| Woofer Cabinet | ported | passive radiator |
| Spinorama Preference Score | 3.66 | 6.33 |
| Spinorama Preference Score with Perfect Sub | 5.61 | 8.28 |
| DIY Kit | No | No |
Related Speaker Comparisons
How AsciLab C6B compares with other leading options:
- 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
Prices on this page were last checked October 9, 2026 at 8:01 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
Klipsch RP-600M: $239.97 per pair Discontinued Amazon eBay
Newer model: the Klipsch RP-600M II, ranked higher, rated 3.7/5. See every Klipsch Reference Premiere generation.
Same family: the Klipsch RP-500M (smaller bookshelf, rated 3.4/5).
Pros: More linear horizontal dispersion than the updated Klipsch RP-600M II: as you move side-to-side, the tonal character changes less, a genuine advantage for off-axis listening consistency. Takes exceptionally well to EQ correction (miniDSP or similar), letting a knowledgeable owner fix its tonal shortcomings without needing to upgrade. Standard 6.5” woofer/horn-tweeter two-way design with reasonably gradual bass rolloff (F3 ~70Hz, F10 ~40Hz) rather than a steep vented-enclosure cutoff. Measured bass extension of 73Hz (-3dB), with a measured sensitivity of 85.2dB.
Cons: A strong, annoying resonance in the lower vocal range around 300Hz stands out clearly (though it can be EQ’d out). Overall tonal balance is notably less neutral than the newer Klipsch RP-600M II, with a roughly 3-4dB suckout in the estimated in-room response. The waveguide doesn’t extend flush to the baffle edge, increasing diffraction compared to the redesigned version. Klipsch’s marketed sensitivity spec (about 96dB) is a half-space, in-room-style rating roughly 9dB above the true anechoic figure (closer to 85-86dB), which can mislead buyers comparing spec sheets. Elevated treble on-axis, similar to its successor, benefits from toe-out or careful placement. Vertical listening tolerance is limited to about ±10° from the tweeter axis. Still needs a subwoofer for real bass weight; a boost around 120Hz gives kick drums their “tambour” without the underlying “meat.”. Discontinued.
Full Klipsch RP-600M review and specifications →
| Bass Extension (-10dB) | 40Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 73Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 15.7”H x 8”W x 11.9”D (398.8 x 203.2 x 302.3 mm) |
| Drivers | 6.5” Cerametallic cone woofer, 1” titanium LTS vented tweeter with Tractrix horn |
| Impedance | 8 ohms nominal, 3.5 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 85.2dB (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 3.66 |
| Spinorama Preference Score with Perfect Sub | 5.61 |
| Weight | 16.1 lbs (7.3 kg) each |
| Woofer Cabinet | ported |
- Links
- Reviews, Comparisons and Sound Samples
- Erin’s Audio Corner: The Truth about Klipsch’s “NEW” Sound. RP-600M Update. More from Erin’s Audio Corner →
- Erin’s Audio Corner Website Klipsch RP-600M
- GR-Research: We Bought The "NEW" RP-600M II Is KLIPSCH Listening?! More from GR-Research →
- Audio Science Review Measurements More from Audio Science Review →
- Audio Science Review Measurements (spinorama.org)
- Head-to-Head Comparisons
- Klipsch RP-600M vs Sonus Faber Lumina II Amator
- Klipsch RP-600M vs Wharfedale Diamond 9.1
- Klipsch RP-600M vs Triangle Borea BR03
- Klipsch RP-600M vs KEF Q350
- Klipsch RP-600M vs Bowers & Wilkins 805S
- Klipsch RP-600M vs Emotiva Airmotiv B2+
- Klipsch RP-600M vs Sonus Faber Sonetto II G2
- Klipsch RP-600M vs Aperion Audio Verus V8B
- See all 38 comparisons
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