Buchardt Audio S400 Bookshelf Speaker Review:‌ ‌My Uncensored Take On A‌ Seductive Speaker!

Buchardt Audio S400 Bookshelf Speaker

Buchardt Audio S400 Bookshelf Speaker








  • Beautiful Design
  • Big, Dynamic Sound
  • Great Build Quality


  • Mids A Little Recessed
  • Needs Care In Partnering

The Buchardt Audio S400 Monitor Speaker is somewhat an enigma in the Audio World, being a direct-to-consumer speaker that is almost impossible to audition before you put some cash down.

However, reviewers have sung its praises for over a year now, and it also received some favorable press from several audio show appearances. The speakers have been so popular in fact, that they were sold out for a period earlier this year.

With all this buzz, some may say hype, of course, people are going out of their way to get some more info on this speaker, and I was no different.

Because of this, I wrote an email to Buchardt Audio to inquire about getting a pair in for review and got a response from none other than the Owner/CEO‌ Mads Buchardt.

He was very gracious and arranged for me to get a loaner pair to try out. Thanks, Mr. Buchardt, for your responsiveness in indulging this humble audio writer’s interest in your product.


Operating principle: 2-way Passive radiator system
Tweeter: 1 x 0,74″ Custom fine weave soft fabric textile with CDC aluminum waveguide
Mid / woofer: 1 x 6″ Aluminum cone with break-up optimization
Passive Radiator: 1 x 5×8″ Long-throw passive radiator with very low mass added
Impedance: 4 ohms
Sensitivity: 88 dB
Frequency response: 33 – 40.000 Hz +/- 3dB (in-room)
Crossover Point: 2000hz
Power recommendation: 40 – 200 W
Measurements (h x w x d): 365 x 180 x 240 mm
Weight: 18 kg / set

Build And Features

So as I‌ said earlier, Buchardt Audio sells the S400 (and its lower-priced sibling, the S300) direct to the consumer on their website, buchardtaudio.com/shop. The price is €1,610.00, which is a little less than $1800 at the time of this writing. They offer a 30-day home trial; if you don’t like them, then they will arrange for return shipping and refund your money.

They design all their speakers in Denmark, then manufacture them in China. They are then sent back to Buchardt’s warehouse for the final QC.

Technically the S400 is a strange animal. But amazingly, the design simultaneously plays into the belief system of the engineers and manages to be stunning.

The huge waveguide framing a tiny dome tweeter, its placement below the 6” midrange, the 5×8 passive radiator occupying almost the whole back of the speaker let you know this is something different before you even hear it.

It’s a serious instrument with purpose, but yet all the components, down to the decorative chrome binding posts, and circular grilles, manage to look like a work of art.

The matte black model they sent me is lovely, but I‌ was hoping to get a look at the white version in person. To me, that one looks outstanding in pics.

I’m not going to break down the why and how of all the design choices here for brevity’s sake, but the company has an excellent page on their website explaining the designer’s thoughts and intentions when putting this speaker together. It’s an elegant and easy read, so if you are interested, I highly recommend you take a look.

To sum it up, this speaker was designed to play big like a floorstander while maintaining the imaging and soundstage capabilities of a mini-monitor. They also wanted to make them easy to place in a variety of listening spaces, so they don’t need a dedicated listening space to sound good.

The huge waveguide and small tweeter are there to enhance off-axis performance. The passive radiator, of course, moves the amount of air needed to reproduce low bass notes. It also alleviates the noise issues associated with ported cabinets like port chuffing, etc.

However, from my understanding, passive radiators are slightly harder to tune, and more expensive to use, which is most likely the leading reason designers don’t use them more.

When it came to setting the speakers up in my space, I first set them up, pointing straight ahead to hear the off-axis response. Since it’s a huge selling point of this speaker, I wanted to listen to what they could do not aimed directly at the listening position.

Buchardt recommends placement about 2-3 ft away from all wall boundaries, and I followed this advice placing the S400 on heavy metal stands about 2 ft out from the walls behind and to the side of them.

They also recommend using an amp with at least 50w per channel into 8 ohms, more if you are placing these speakers in a larger room.

It’s also worthy to note these are 4-ohm speakers, so I‌ wouldn’t recommend paring them with an 8-ohm mass-market receiver, they require some gusto to get going.

I hooked them up to my reference integrated, the Audiolab 6000A, it is capable of a genuine 75w into 4 ohms. I used the Audiolab 6000N PLAY streamer as a source streaming Tidal files and 24-bit music files from my NAS‌ drive.

Listening to the S400

Even though I‌ started out listening with the speakers pointed straight ahead, I found their focus and soundstage to be much better with the speakers arranged in standard equilateral triangle placement.

The passive radiators provide a generous low end for a standmount speaker, with bass volume and depth very close to what you get from a full-range floorstanding model. The scale remarkably resembles a tower speaker as well. The overall presentation is warm.

Treble is somewhat laid back but sweet, providing the level of detail needed to provide clarity and focus at that end of the spectrum.

This speaker’s prowess on both extremes of the audioband goes well with modern music. For example, when I cranked up “DNA.” by Kendrick Lamar, they drove the song home, reproducing the foundational bass rumble with a force not many standmount speakers can match.

At the same time, the clean treble provided air at the top allowing the music to expand beyond the speakers and breathe. It was exhilarating.

However, when I‌ switched over to my favorite Genre, which is Jazz Vocals, I‌ found that the midrange a little veiled and closed in. On “These Things”‌ by Luciana Souza, her voice was a bit dull, and I had problems hearing the variations in her phrasing as I do with other monitor speakers.

However, when I paired them up with my Emotiva integrated, which has a more forward sound than the Audiolab, it did open up the mids a bit, so it shows some care in pairing may be necessary.

With their positioning dialed in, the soundstage was vast and deep, playing way out all around the speakers, sounding holographic with certain songs. The sound was immersive when I listened to “Touch” from Daft Punk. If you check these out, don’t be afraid to toe them in and out, and find the right spot. When they are on, they are on.


For the money, you get a lot with the S400. If you are looking for a speaker that is very close to full-range and fits on a 24” stand, these are worth listening to. I really can’t think of another speaker at their size, especially under $2000, that does what these do with sheer dynamics. When they get going, you can feel the bass in your chest!

I once read a reviewer say that a particular speaker plays “Songs”‌ instead of playing “Things”‌ and that’s kinda how I‌ feel about these. They are not super analytical, but they give you the feeling of the music, especially if you listen to a lot of electronic and heavy bass music.

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