Short answer: the Buchardt S400 MK3 for better sound quality, the Klipsch RP-600M II for the lower price. The Buchardt S400 MKII ranks higher than the Klipsch RP-600M II (#112 vs #124 of 223 bookshelf speakers) but is discontinued. Its replacement, the Buchardt S400 MK3, is rated 4.0/5 at $2,300; the Klipsch RP-600M II is rated 3.7/5 at $449.99, $1,850.01 cheaper.
What the Klipsch RP-600M II does well: Bookshelf speakers with a large horn tweeter, wide soundstage, high efficiency and bi-amp ready terminals. The tradeoff: On-axis, the treble runs notably hot (even hotter than the original Klipsch RP-600M in some respects) and needs about 20° of toe-out or the grille installed to sound balanced.
The Buchardt S400 MKII is the deeper-bass choice. Bookshelf speakers with very flat sound, precise imaging and adjustable bass, now discontinued but worth buying used. Its bass reaches about 59Hz before falling 3dB, against 70Hz for the Klipsch RP-600M II. The catch: 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.
Buy the Klipsch RP-600M II if price matters most. For better sound quality, the Buchardt S400 MK3, the replacement for the discontinued Buchardt S400 MKII, is rated higher but costs $2,300.
Want more options? Browse the full Passive Home rankings.
Bookshelf speakers with a large horn tweeter, wide soundstage, high efficiency and bi-amp ready terminals.
Bookshelf speakers with very flat sound, precise imaging and adjustable bass, now discontinued but worth buying used.
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Specifications Side By Side
| Klipsch RP-600M II | Buchardt S400 MKII | |
|---|---|---|
| Price | $449.99 per pair | $2400 per pair Discontinued |
| Ranked | #124 of 223 in Large Size Bookshelf Speakers | #112 of 223 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 | 5.64 | 5.38 |
| Spinorama Preference Score with Perfect Sub | 7.77 | 7.46 |
| 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.
Measurement data: Klipsch RP-600M II (measured by Erin’s Audio Corner) and Buchardt S400 MKII (measured by Erin’s Audio Corner), via spinorama.org.
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