Short answer: the Buchardt S400 MKII for better sound quality, the Klipsch RP-600M II for the lower price. The Buchardt S400 MKII ranks #64 of 130 bookshelf speakers at $2400. The Klipsch RP-600M II ranks #74 at $449.99, $1950.01 cheaper.
What the Klipsch RP-600M II offers: Redesigned waveguide extends flush to the baffle edge, reducing diffraction compared to the original RP-600M. Roughly 10-20° wider horizontal radiation than the original, giving more soundstage envelopment while retaining precise imaging. A major step up in overall tonal neutrality compared to the original RP-600M, largely eliminating that model’s midrange resonance issues. Unusually, sounds better with the grille on - the grille smooths out the elevated treble rather than degrading the sound, a rare trait among speakers the reviewer has tested. More refined back-panel hardware, including anodized binding posts and jumper cables for optional bi-amping. Responds well to EQ correction (verified using measurement software and a miniDSP), letting the on-axis response be made genuinely linear. Watch for: On-axis, the treble runs notably hot - even hotter than the original RP-600M in some respects - and needs about 20° of toe-out or the grille installed to sound balanced. Horizontal dispersion is very slightly less linear across angles than the original RP-600M, a minor trade-off for the wider overall radiation pattern. Klipsch’s marketed sensitivity (about 94.5dB) is, like the original, a half-space rating roughly 9dB above the anechoic reality (closer to 85-86dB). In-room bass rolls off around 60Hz in practice, and a 120Hz boost paired with a midrange scoop gives kick drums their “tambour” without real low-end weight - a subwoofer is still recommended. Vertical listening tolerance is limited to about ±10° from the tweeter axis. Toeing the speaker out for better on-axis tonality (rather than using the grille) introduces slightly more diffuse imaging from added sidewall reflections.
What the Buchardt S400 MKII offers: Two-way design with a 3/4” tweeter on a well-implemented aluminum waveguide (compression-driver style, letting the small tweeter cross unusually low at 1800Hz), a 6” SB Acoustics-style mid-woofer, and a tunable 5x8” passive radiator adjustable via rear weights. Exceptionally flat on-axis linearity, within about ±2dB from 80Hz to 16kHz. Wide horizontal radiation for a waveguided design (about ±45-50°), notably broader than a comparable narrow-waveguide rival like the Klipsch Sevens (~±30°). Well-focused, precise imaging, aided by tight pair matching between the two speakers. Takes very well to EQ correction, letting listeners easily dial in the top end or add midrange fullness to taste. Bass extension reaches a genuine 50Hz in-room from a mellow, well-tuned rolloff rather than an artificially boosted one. Watch for: Sounds a bit bright and slightly boosted above about 7-8kHz on-axis, even with 30° of toe-out - benefits from about 1 inch of sidewall absorption at the first reflection points to tame it. A mild dullness noted especially on male vocals, alongside a small dip around 300-600Hz. Vertical positioning is critical and unusually “temperamental” - sitting even slightly toward the tweeter line causes a suckout, while sitting above it adds too much energy; not well suited to multi-height home theater seating. Distortion is fine at 86dB but runs into real issues by 96dB - not a high-output speaker. Some compression-related enhancement appears around 1.2kHz (crossover-region interaction), and the tweeter shows clear compression at 102dB. The woofer can bottom out at extreme low-frequency content played very loud; crossing to a subwoofer below 60Hz caused output problems at high volume, while 80-100Hz worked well. A subwoofer isn’t strictly required to protect the speaker at moderate listening levels (80-85dB at 3 meters), but is still recommended for genuine low-octave extension.
Buy the Klipsch RP-600M II when the price outweighs sound quality for you, and the Buchardt S400 MKII when sound quality outweighs the price instead.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| Klipsch RP-600M II | Buchardt S400 MKII | |
|---|---|---|
| Price | $449.99 per pair | $2400 per pair |
| Ranked | #74 of 130 in Large Size Bookshelf Speakers | #64 of 130 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 41Hz (measured, Erin's Audio Corner) | 40Hz (measured, Erin's Audio Corner) |
| Bass Extension (-3dB) | 70Hz (measured, Erin's Audio Corner) | 59Hz (measured, Erin's Audio Corner) |
| Dimensions | 15.7"H x 8"W x 12.5"D (398.8 x 203.2 x 317.5 mm) | 14.4"H x 7"W x 11"D (365.8 x 177.8 x 279.4 mm) |
| Impedance | 8 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin's Audio Corner) | 4 ohms nominal, 3 ohms minimum (measured, Erin's Audio Corner) |
| Sensitivity | 86dB (measured, Erin's Audio Corner) | 84.7dB (measured, Erin's Audio Corner; 87dB manufacturer specified) |
| Drivers | 6.5" Cerametallic cone woofer, 1" titanium LTS vented tweeter with Tractrix horn | 6.5" aluminum cone woofer, 1" soft dome tweeter |
| Weight | 13 lbs (5.9 kg) each | 16.5 lbs (7.5 kg) each |
| Woofer Cabinet | ported | ported |
| Spinorama Preference Score | 4.75 | 4.47 |
| Spinorama Preference Score with Perfect Sub | 6.88 | 6.55 |
Related Speaker Comparisons
How Buchardt S400 MKII compares with other leading options:
- ELAC VELA BS 403 vs Buchardt S400 MKII
- Philharmonic BMR (v1) vs Buchardt S400 MKII
- ELAC Debut 3.0 DB63 vs Buchardt S400 MKII
- Buchardt S400 MKII vs Philharmonic BMR Monitor
- Buchardt S400 MKII vs Pylon Jasper Monitor 18
Prices on this page were last checked September 14, 2026 at 1:47 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.
As an eBay Partner, we may be compensated if you make a purchase.
The Two Speakers In Full
Klipsch RP-600M II: $449.99 per pair Amazon eBay
Pros: Redesigned waveguide extends flush to the baffle edge, reducing diffraction compared to the original RP-600M. Roughly 10-20° wider horizontal radiation than the original, giving more soundstage envelopment while retaining precise imaging. A major step up in overall tonal neutrality compared to the original RP-600M, largely eliminating that model’s midrange resonance issues. Unusually, sounds better with the grille on - the grille smooths out the elevated treble rather than degrading the sound, a rare trait among speakers the reviewer has tested. More refined back-panel hardware, including anodized binding posts and jumper cables for optional bi-amping. Responds well to EQ correction (verified using measurement software and a miniDSP), letting the on-axis response be made genuinely linear. Measured bass extension of 70Hz (-3dB), with a measured sensitivity of 86dB.
Cons: On-axis, the treble runs notably hot - even hotter than the original RP-600M in some respects - and needs about 20° of toe-out or the grille installed to sound balanced. Horizontal dispersion is very slightly less linear across angles than the original RP-600M, a minor trade-off for the wider overall radiation pattern. Klipsch’s marketed sensitivity (about 94.5dB) is, like the original, a half-space rating roughly 9dB above the anechoic reality (closer to 85-86dB). In-room bass rolls off around 60Hz in practice, and a 120Hz boost paired with a midrange scoop gives kick drums their “tambour” without real low-end weight - a subwoofer is still recommended. Vertical listening tolerance is limited to about ±10° from the tweeter axis. Toeing the speaker out for better on-axis tonality (rather than using the grille) introduces slightly more diffuse imaging from added sidewall reflections.
Full Klipsch RP-600M II review and specifications →
| Bass Extension (-10dB) | 41Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 70Hz (measured, Erin's Audio Corner) |
| Dimensions | 15.7"H x 8"W x 12.5"D (398.8 x 203.2 x 317.5 mm) |
| Drivers | 6.5" Cerametallic cone woofer, 1" titanium LTS vented tweeter with Tractrix horn |
| Impedance | 8 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin's Audio Corner) |
| Sensitivity | 86dB (measured, Erin's Audio Corner) |
| Spinorama Preference Score | 4.75 |
| Spinorama Preference Score with Perfect Sub | 6.88 |
| Weight | 13 lbs (5.9 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 II
- GR-Research: We Bought The "NEW" RP-600M II Is KLIPSCH Listening?! More from GR-Research →
- Erin’s Audio Corner: 5 AWESOME SPEAKERS Under $1000 You Won’t Regret
- Erin’s Audio Corner Measurements (spinorama.org)
- Head-to-Head Comparisons
- Klipsch RP-600M II vs Dynaudio Emit 20
- Klipsch RP-600M II vs Philharmonic BMR Monitor
- Klipsch RP-600M II vs JBL Studio 630
- Klipsch RP-600M II vs Behringer B2030P
- Klipsch RP-600M II vs Ascend CBM-170 SE2
- Klipsch RP-600M II vs Infinity Reference R162
- Klipsch RP-600M II vs GR-Research X-LS Encore
- Klipsch RP-600M II vs Infinity IL10
- See all 72 comparisons
Buchardt S400 MKII: $2400 per pair Buchardtaudio eBay
Pros: Two-way design with a 3/4” tweeter on a well-implemented aluminum waveguide (compression-driver style, letting the small tweeter cross unusually low at 1800Hz), a 6” SB Acoustics-style mid-woofer, and a tunable 5x8” passive radiator adjustable via rear weights. Exceptionally flat on-axis linearity, within about ±2dB from 80Hz to 16kHz. Wide horizontal radiation for a waveguided design (about ±45-50°), notably broader than a comparable narrow-waveguide rival like the Klipsch Sevens (~±30°). Well-focused, precise imaging, aided by tight pair matching between the two speakers. Takes very well to EQ correction, letting listeners easily dial in the top end or add midrange fullness to taste. Bass extension reaches a genuine 50Hz in-room from a mellow, well-tuned rolloff rather than an artificially boosted one. Measured bass extension of 59Hz (-3dB), with a measured sensitivity of 84.7dB.
Cons: Sounds a bit bright and slightly boosted above about 7-8kHz on-axis, even with 30° of toe-out - benefits from about 1 inch of sidewall absorption at the first reflection points to tame it. A mild dullness noted especially on male vocals, alongside a small dip around 300-600Hz. Vertical positioning is critical and unusually “temperamental” - sitting even slightly toward the tweeter line causes a suckout, while sitting above it adds too much energy; not well suited to multi-height home theater seating. Distortion is fine at 86dB but runs into real issues by 96dB - not a high-output speaker. Some compression-related enhancement appears around 1.2kHz (crossover-region interaction), and the tweeter shows clear compression at 102dB. The woofer can bottom out at extreme low-frequency content played very loud; crossing to a subwoofer below 60Hz caused output problems at high volume, while 80-100Hz worked well. A subwoofer isn’t strictly required to protect the speaker at moderate listening levels (80-85dB at 3 meters), but is still recommended for genuine low-octave extension.
Full Buchardt S400 MKII review and specifications →
| Bass Extension (-10dB) | 40Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 59Hz (measured, Erin's Audio Corner) |
| Dimensions | 14.4"H x 7"W x 11"D (365.8 x 177.8 x 279.4 mm) |
| Drivers | 6.5" aluminum cone woofer, 1" soft dome tweeter |
| Impedance | 4 ohms nominal, 3 ohms minimum (measured, Erin's Audio Corner) |
| Sensitivity | 84.7dB (measured, Erin's Audio Corner; 87dB manufacturer specified) |
| Spinorama Preference Score | 4.47 |
| Spinorama Preference Score with Perfect Sub | 6.55 |
| Weight | 16.5 lbs (7.5 kg) each |
| Woofer Cabinet | ported |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons