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Buchardt S400 Speaker Review

amirm

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#1
This is a review and detailed measurements of the Buchardt S400 2-way stand-mount speaker. It was kindly sent to me by the company for testing. As best as I can tell, it is sold by the company direct and costs €1,800 per pair which translates to US $1,950 as of this writing. Interestingly the cost is inclusive of any import duties and taxes! The warranty is a generous 10 years.

The S400 nails the industrial design, showing a highly differentiated and modern look in a loudspeaker:
Buchardt S400 bookshelf speaker audio review.jpg


Success in speaker business is 80% marking and I think Buchardt has nailed that with this look and feel.

The back panel of a speaker is usually boring but not in this case:

Buchardt S400 bookshelf speaker back panel passive radiator audio review.jpg


Instead of a port we have a passive radiator which is said to eliminate the noise from the port. In listening tests, that seems to be case with me only hearing nice low frequencies and not much else from the back.

Terminals are nicely spaced and easy to use.

The S400 is designed in Denmark but manufactured in China. I was a bit surprised that at this price point is not locally produced. Not that this matters to me personally.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

All measurements are referenced to the tweeter axis with frequency resolution of 2.7 Hz.

As an aside, the S400 has been measured with the same Klippel NFS system so makes for an interesting comparison between my data and theirs.

To Center or Not to Center -- that is the question!
The manual states that the listening axis vertically should be between the tweeter waveguide and woofer. This is contrary to my usual measurement standard of tweeter axis. To avoid the food fights we get every time this comes up, I actually measured the S400 twice: once at tweeter axis and then at the recommended "acoustic center." I did this both in-room (not shown) and with full NFS scan. Here is the latter comparison of on-axis with both overlayed:

Buchardt S400 bookshelf speaker Reference Axis Audio Measurements.png


Please ignore the response in red beyond 8 kHz or so. When the reference axis is not the tweeter, the estimation of sound field becomes less accurate at higher frequency in NFS system requiring far more measurement points than I was willing to spend to measure it. Presumably if fixed, it will tilt back up and be similar to tweeter axis.

Anyway, the direct axis in my opinion suffers when you select the mid-point between the two drivers with the dip starting at crossover frequency becoming more pronounced. So for the rest of the measurements, I opted to use the tweeter axis data.

Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker can be used. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

Buchardt S400 bookshelf speaker CEA-2034 spinorama frequency response audio measurement.png


The on-axis/listening window is fairly flat and desirable. What is not is the peak at 518 Hz or so which as you will see in other measurements is very persistent. Company measurements show the same although not as exaggerated.

Despite the highly visible waveguide intending to limit the directivity (how wide the sound spreads) of the tweeter to match that of the woofer, it seems to not be at optimal position relative crossover frequency. The same is seen in horizontal directivity plot:

Buchardt S400 bookshelf speaker horizontal directivity Audio Measurements.png


Notice how the woofer is getting more directional with its soundfield shrinking. The tweeter than takes over but it does so a bit later, causing that dip and mismatch. Company measurements are a bit different and more optimized. So maybe there is sample to sample variation in the crossover?

Predicted in-room response in a hypothetical room shows the same issues we have seen so far:

Buchardt S400 bookshelf speaker CEA-2034 spinorama Predicted In-room frequency response audio ...png


Our waterfall/CSD plot shows the resonance issue around 500 Hz:

Buchardt S400 bookshelf speaker CSD waterfall Audio Measurements.png


Vertical directivity shows that the optimal axis is the tweeter:

Buchardt S400 bookshelf speaker Vertical directivity Audio Measurements.png


If you go up in angle, you hit that dip as I showed in my introductory measurement of reference axis.

Interesting to see the higher amplitude low frequency response above axis. I am assuming this is due to woofer being on top but there should not be that much directivity there in such low frequencies. Maybe it is the cabinet that is radiating on one side more than the other?

This is a low impedance speaker for a much of the frequency band:

Buchardt S400 bookshelf speaker Impedance and phase Audio Measurements.png


And because of that, it stays at that low impedance even when phase angle goes negative and positive, creating a more difficult load for the amplifier.

Finally distortion measurements:
Buchardt S400 bookshelf speaker Distortion Percent THD Audio Measurements.png


Buchardt S400 bookshelf speaker Distortion THD Audio Measurements.png


Speaker Listening Tests
The first impression was not very positive. Going through my track list, not much excited me. I put in a filter at the resonance point and that helped fair but but I was still left empty. My reference tracks all sounded good but hardly any sounded great.

I physically examined the speaker and boy does this cabinet breath. It is constantly being excited by whatever it plays. On other speakers, only a few frequencies excited them but here, the cabinet is more like how a music instrument acts, being part of the show. Researching online, it seems the cabinet has no bracing and is only using half inch MDF?

Upper bass delivery was good (e.g. in techno music) but deep bass at elevated levels would cause severe bottoming out of the woofer. I swapped the S400 for the Revel M16 and found it having the same issue. But otherwise, it sounded excellent and much better performer on my reference tracks. The M16 costs half as much so this did not bode well for the S400.

I no longer have the JBL HDI-1600 but from memory it did a lot better than the Revel M16 in handling deep bass. In addition, the JBL aced all of my reference tracks as well.

I should say that overall sound of the S400 is pleasant and warm. And often times I would admire mid to high frequency transient notes. So there is merit here.

Conclusions
Whenever I get equipment from companies, I hold my breath as I measure them, hoping hard that they do well. Here, the Buchardt objectively performs reasonably well. At this price though, I expect a more stout cabinet, free of clear resonances and copious vibration. And with the waveguide being the center of attention, it would be good to have perfection at the crossover point.

Combined with the subjective listening experience which left me mostly unsatisfied, I cannot recommend the Buchardt S400. I hope the company makes some improvements to the design as the have a good overall recipe. Alternatively, they could decide I don't know what I am listening to and go about their business. :)

EDIT: on further reflection, I think I did not do a good job of highlighting what the Buchardt S400 does well. And that is excellence in a lot of the objective measurements. Indeed its performance there is better than some speakers I have liked and recommended! As usual, objective data is much more reliable than any subjective impressions I have of a speaker. So I would say put the S400 on your target list of speakers to evaluate as it certainly passes the bar of being objectively good.

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As always, questions, comments, recommendations, etc. are welcome.

As you all know, panthers hunt and eat live animals. I have been feeding mine grocery store meet. To confuse them into thinking that they are live animals, I play sounds of such as I prepare their food. Well, I made a mistake and fed them some beef that had a grocer store sticker on it and now have a serious problem on my hand. They are demanding that I buy them livestock to eat. Not sure how to solve that problem just yet but I do know having money helps. So please donate what you can using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

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amirm

amirm

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Thread Starter #4
It would certainly be good to get a second set of eyes (measurements) and ears on these to confirm or dispute what I have found....
 

edechamps

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#5
I have added the Buchardt S400 to Loudspeaker Explorer where it can be compared to other speakers.

Good consistency within the listening window… but don't put these below ear height, as @amirm mentioned in his review:

visualization(68).png
 

Koeitje

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#7
The woofer looks like the woofer used on the Performa3 series from Revel? Its only 6" though?
 

MZKM

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#8
No distortion graph?

This is a low impedance speaker for a much of the frequency band:



And because of that, it stays at that low impedance even when phase angle goes negative and positive, creating a more difficult load for the amplifier.
I thin you meant "(with phase below 30 degrees)".
 
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#9
I heard them recently too. I mostly enjoyed them, specifically their wide soundtage and imaging. However as you also noted their biggest problem for me was the woofer breaking up. I almost thought I broke them and my heart sank as they were from a customer that brought them in (I work at a Hi-Fi integrator in Maryland). Thankfully that wasn't actual damage just the woofer losing control. My usual reference is either the Totem Acoustic Metal V2 tower, Fire V2 bookshelf, or their Tribe tower depending on another speaker's size and price point. When compared to Tribe tower (granted these are $5,000 a pair) the breakup was even more annoying. I enjoy the Totem's for their sense of images and width as well, but with great speed for a dynamic driver speaker. However that is a speaker in which a small driver can actually play low and with control thanks to the great motor structure. Maybe some bracing and improved magnet strength can help Buchardt. I am still excited to see what their new actives will do though. Maybe the copious power and DSP will help as my experience with Wisdom Audio products which use an active crossover and calibration certainly displays to me the advantages of doing so.
 
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jam

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#10
Very interesting and eye (ear?) opening review. Thanks once more Amir. I was expecting a more glowing review from these as they've become very popular lately. You see them all over the place on YouTube with very high recommendations. Of course all those reviews are purely subjective, which is what sets ASR apart from the crowd all too eager to give high passing grades in order to cash in.
 

q3cpma

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#12
While it does look good, it also looks like a complete Amphion ripoff, as far as design goes. Overall, I'm quite disappointed: I expected a lot, for some reasons. Being built in China at this price point matters to some and the fallings (BBC tier cabinet and directivity mismatch) should have been easy to solve.

As said, no distorsion measurement? That distorsion peak is perfectly aligned with the dip following the resonance in the frequency response (power response is smooth at that exact point, probably something else).
Besides, distorsion is quite high under 300 Hz, a passive radiator thing?

Basically, the R3 is still the benchmark in the passive $1500-2000 range.
LMAO. Man, talk about timing. A pair for me to review is due today. I’m gonna have to avoid reading this until I do my own subjective evaluation. But I look forward to seeing the data tomorrow. LOL.
That'll be very useful!
 
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Haint

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#13
Looks like a good speaker overall, but too pricey relative to its competitors and performance.
 
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amirm

amirm

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Thread Starter #15
I thin you meant "(with phase below 30 degrees)".
No I meant if you include the effect of phase, then it is actually below 3 ohm.
 

gr-e

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#16
To Center or Not to Center -- that is the question!
The manual states that the listening axis vertically should be between the tweeter waveguide and woofer. This is contrary to my usual measurement standard of tweeter axis. To avoid the food fights we get every time this comes up, I actually measured the S400 twice: once at tweeter axis and then at the recommended "acoustic center." I did this both in-room (not shown) and with full NFS scan. Here is the latter comparison of on-axis with both overlayed:
It looks like you changed the expansion point instead of the reference axis again (as you did with KH80), hence the error at high frequencies.
The actual measurement between woofer and tweeter should correspond to +2.5 degree vertical measurement.
 

Bamyasi

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#17
Have you given them some break-in time before measuring? Buchardt recommends 100 hours minimum which I found a bit extreme but in fact, these are the only pair of speakers in my memory (apart from a few subs) that actually did require break-in to sound even remotely normal, not to say great. At least 10-12 hours are necessary since out of the box their woofer is simply not working at all, as if it is stuck. This is by design, so they say in the documentation.
 
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amirm

amirm

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Thread Starter #19
Huh, I’ve never seen that done.
It is done elsewhere but not often. Hifi news for example actually computes the equiv impedance.
 
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