Short answer: the Buchardt S400 MK3 is the newer model that replaces the Buchardt Audio S400, but only the Buchardt Audio S400 has been measured and ranked so far, so this comparison is on specs and features rather than sound. The Buchardt Audio S400 is discontinued, so it is now a used buy.
What the Buchardt S400 MK3 offers: A ground-up redesign of the S400 with an 18 percent larger cabinet and a 7.5” SB Acoustics Satori Papyrus paper cone woofer, which Buchardt says has 65.5 percent more displacement than the MKII’s 6” driver.
What the Buchardt Audio S400 brings: Compact passive design with a 6-inch aluminum woofer, rear passive radiator and waveguided 0.74-inch tweeter positioned below the woofer.
Buy the Buchardt Audio S400 if you want a speaker whose sound quality has been measured and ranked.
Buy the Buchardt S400 MK3 if you want the newer model, and you can wait for measurements to confirm how it sounds.
Still deciding? The full Passive Home rankings cover every ranked option.
Specifications Side By Side
| Buchardt S400 MK3 | Buchardt Audio S400 | |
|---|---|---|
| Price | $2,300 per pair | €1,800 per pair Discontinued |
| Ranked | - | #29 of 131 in Large Size Bookshelf Speakers |
| Crossover Frequency | 2.2kHz (first order) | - |
| Dimensions | 392H x 198W x 280D mm | 14.8”H x 7.1”W x 9.6”D (375 x 180 x 245 mm) |
| DIY Kit | No | No |
| Drivers | 1” aluminum dome tweeter in waveguide, 7.5” Satori Papyrus paper cone woofer | 0.74” waveguided tweeter; 6” aluminum woofer |
| Frequency Response | 33Hz - 20kHz (in-room, manufacturer specified) | - |
| Impedance | 4 ohms | 3.7 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 87dB anechoic, 90dB in-room (manufacturer specified) | Approximately 86dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Weight | 8.5 kg each | 16.1 lbs (7.30 kg) each |
| Woofer Cabinet | ported, rear | sealed with rear passive radiator |
| Bass Extension (-3dB) | - | 53Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | - | 38Hz (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | - | 5.23 |
| Spinorama Preference Score with Perfect Sub | - | 7.43 |
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The Two Speakers In Full
Buchardt S400 MK3: $2,300 per pair Buchardt Audio eBay
Older models: the Buchardt Audio S400 (rated 4.4/5) and the Buchardt S400 MKII (rated 3.8/5).
Pros: A ground-up redesign of the S400 with an 18 percent larger cabinet and a 7.5” SB Acoustics Satori Papyrus paper cone woofer, which Buchardt says has 65.5 percent more displacement than the MKII’s 6” driver. A custom 1” aluminum dome tweeter sits in a new waveguide, crossed at 2.2kHz with a first order Jantzen crossover. Buchardt rates in-room bass extension to 33Hz and anechoic sensitivity at 87dB, and includes foam port plugs to trim bass near a wall. Sold direct with free worldwide shipping, duties included, and a 10 year warranty for the first owner.
Cons: No independent measurements have been published yet. The S400 MKII measured very well, but the MK3 shares only its binding posts, so that result can’t be carried over and its linearity, directivity and real bass extension are unknown. The 33Hz figure is an in-room number, not an anechoic one. The MKII’s adjustable passive radiator is gone in favor of a rear port that wants at least 5cm from the wall. A 4 ohm load means it needs an amplifier comfortable driving 4 ohms, and it is sold only direct from Buchardt.
Full Buchardt S400 MK3 review and specifications →
| Crossover Frequency | 2.2kHz (first order) |
|---|---|
| DIY Kit | No |
| Dimensions | 392H x 198W x 280D mm |
| Drivers | 1” aluminum dome tweeter in waveguide, 7.5” Satori Papyrus paper cone woofer |
| Frequency Response | 33Hz - 20kHz (in-room, manufacturer specified) |
| Impedance | 4 ohms |
| Sensitivity | 87dB anechoic, 90dB in-room (manufacturer specified) |
| Weight | 8.5 kg each |
| Woofer Cabinet | ported, rear |
- Links
- Reviews, Comparisons and Sound Samples
- These figures are manufacturer-specified rather than independently measured.
- Head-to-Head Comparisons
Buchardt Audio S400: €1,800 per pair Discontinued eBay
Newer model: the Buchardt S400 MK3. It’s likely to perform similarly, though we can’t confirm that yet.
Pros: Compact passive design with a 6-inch aluminum woofer, rear passive radiator and waveguided 0.74-inch tweeter positioned below the woofer. Erin measured F3/F10 at 53Hz/38Hz, approximately 86dB/2.83V/1m sensitivity and smooth, broad horizontal directivity. The waveguide controls crossover handoff effectively, the passive radiator avoids port chuffing, and Erin heard no objectionable narrow-band distortion despite excellent extension for the enclosure volume. Measured bass extension of 53Hz (-3dB), with a measured sensitivity of 86dB.
Cons: The impedance reaches 3.7 ohms (Erin), so a genuinely four-ohm-stable separate amplifier is recommended rather than a basic AVR. Low-frequency distortion naturally rises at high output and the compact woofer cannot supply theater-level deep bass; crossing to a subwoofer protects headroom. Erin measured narrow distortion features above 8-9kHz and vertical lobing outside the intended axis. This is the original S400, distinct from the S400 MKII already ranked. Discontinued.
Full Buchardt Audio S400 review and specifications →
| Bass Extension (-10dB) | 38Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 53Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 14.8”H x 7.1”W x 9.6”D (375 x 180 x 245 mm) |
| Drivers | 0.74” waveguided tweeter; 6” aluminum woofer |
| Impedance | 3.7 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | Approximately 86dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 5.23 |
| Spinorama Preference Score with Perfect Sub | 7.43 |
| Weight | 16.1 lbs (7.30 kg) each |
| Woofer Cabinet | sealed with rear passive radiator |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons