In this review, we will be comparing S400 and Q150, two Passive Bookshelf speakers from Buchardt and KEF.
Let's have a brief look at the main features
of Buchardt S400 and KEF Q150 first before getting into our more
detailed comparison.
| Key Specs | Buchardt S400 | KEF Q150 |
|---|
| Brand | Buchardt
Denmark · founded 2014 | KEF
United Kingdom · founded 1961 |
|---|
| Design | 2-way | 2-way |
|---|
| Uni-Q driver | — | 11th Generation Uni-Q |
|---|
| Tweeter | 0.74" aluminum waveguide | 1" Dome |
|---|
| Woofer | 6" paper | 5.25" Aluminum |
|---|
| Frequency response | 33-40 kHz | 51-28k Hz |
|---|
| Sensitivity | 88 dB | 86 dB |
|---|
| Impedance | 4 ohms | 8 ohms |
|---|
| Power range | 40-200 watts | 10-100 watts |
|---|
| Weight | 7.30kg / 16.1lbs | 5.60kg / 12.3lbs |
|---|
| Dimensions (H x W x D) | 14.75" x 7" x 9.65"
375 x 180 x 245mm | 11.9" x 7.0" x 10.9"
303.0 x 180.0 x 278.0mm |
|---|
What size room are the Buchardt S400 and KEF Q150 speakers good for?
The size of the room in which you are planning to use these loudspeakers is an important decision
factor. Here we have compared their suitability to various sizes of environments considering their size
and max power parameters:
| Listening Environment* |
Buchardt S400 |
KEF Q150 |
| Near-field |
Poor |
Average |
| Small Room |
Average |
Good |
| Mid-size Room |
Good |
Average |
| Large Room |
Average |
Poor |
| Very Large Room |
Poor |
Bad |
(* Approximate Room sizes: Small < 100sq. ft / 9 m2,
Mid-size: 100-220 sq. ft / 9-20 m2, Large 220-400 sq. ft / 20-36 m2, Very Large: >
400 sq. ft / 36 m2.
Average Floor Height: 9" / 2.7m. Typical room sizes differ from country to country, and the actual
listening experience changes depending on floor height, room shape, surface materials, listening
position, speaker locations, etc.)
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both S400 and Q150 are 2-way speakers.
Buchardt S400KEF Q150
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Buchardt S400 |
KEF Q150 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
0.74-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 6-inch
|
1 x 5.25-inch
|
S400 features a 0.74" Custom fine weave soft fabric textile aluminum waveguide Tweeter and 1 x 6" paper Woofer with a Crossover frequency at 2000Hz. On the other hand, the Q150 features a 1" vented aluminum Dome Tweeter and 1 x 5.25" Aluminum Woofer with a Crossover frequency at 2500Hz.
Frequency Response
S400 has a frequency range of 33-40 kHz whereas Q150 has a frequency range of 51-28k Hz. With a minimum frequency of 33Hz, the S400 can go significantly deeper on the low side and provide stronger bass compared to the Q150's min frequency of 51Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
Neither pair reaches down to 20Hz, the usual definition of full-range, which is normal for speakers of this size. If you want the bottom octave for movies or bass-heavy music, add a subwoofer to whichever you choose. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
S400 is a 4 ohms speaker compared to the Q150 which has a nominal impedance of 8 ohms. Lower impedance speakers, especially the ones that are rated at 4 ohms may put more pressure on the amplifier unit especially when played at high volume levels, so make sure the amp you pair with the S400 can provide this impedance level.
These two speakers also have different sensitivity levels. S400 sensitivity is rated at 88 dB and the Q150's is rated at 86 dB. This 2 dB difference makes the Buchardt S400 a more sensitive speaker compared to KEF Q150, hence will play louder with the same amount of watts.
Sensitivity
Bookshelf Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
S400 can handle a max power of 200 watts RMS, whereas Q150 has a max power handling value of 100 watts RMS, 100 watts less than the S400.
Note that higher power handling does not make a speaker louder: that depends mainly on
sensitivity and impedance. The calculator below shows how loud each of these actually plays
on a real amplifier.
Which plays louder on your amplifier?
Starting with a popular amplifier - change it to the one you own, or any you are
considering, and watch both numbers move.
KEF Q150 Port
Physical Specs
The size of a speaker can sometimes be an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare Buchardt S400's and KEF Q150's external dimensions. Buchardt S400 has external dimensions of 375 x 180 x 245mm (14.75 x 7 x 9.6inch) whereas KEF Q150 has external dimensions of 303.0 x 180.0 x 278.0mm (11.9 x 7.0 x 10.9inch).
Below you can see the front view size comparison of Buchardt S400 and KEF Q150 in scale.
Comparison image of Buchardt S400 and KEF Q150 Size and External Dimensions
Base Surface Area Comparison
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base surface area of the Buchardt S400 is approximately 441.0cm2 / 68.4inch2 and base area of the KEF Q150 is approximately 500.4cm2 / 77.6inch2. The S400 requires 12% less surface area than the Q150 which gives it a small advantage on placement in tight spaces.
Here is another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:
Size Comparison image of Buchardt S400 and KEF Q150 on a Media Console
Weight Comparison The weight of a loudspeaker can become an important factor if you need to move and reposition the unit often. Weight of a speaker can also "sometimes" be an indicator of the rigidity of the enclosure and the quality of the internal components used. The Buchardt S400 weighs 7.30kg / 16.1lbs and the KEF Q150 weighs 5.60kg / 12.3lbs. This makes the S400 30% heavier than the Q150.
Here is a comparison of how S400 and Q150's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of KEF Q150?
Here are the items that come with the Q150:
- 2 Bookshelf loudspeakers
- 2 Foam port plugs
- 8 Self-adhesive rubber feet
- Owner's Manual
- Warranty Registration Card
 Max Input Power |
200 watts
vs
100 watts
|
Handle more power from your amplifier |
 Sensitivity |
88 dB
vs
86 dB
|
Play louder with same amount of amplification power |
 Woofer Size |
6 inches
vs
5.25 inches
|
Larger woofer |
|
Low Frequency Response |
33 Hz
vs
51 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
28k Hz
|
Generates higher frequency |
 Passive Radiator |
one 5x8-inch
vs
None
|
Increases the bass performance |
 Base Surface Area |
441cm2
vs
500cm2
|
Takes less floor space |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
 Height |
303mm
vs
375mm
|
Easier to fit in smaller spaces |
| General |
Buchardt S400 |
KEF Q150 |
| Brand |
Buchardt |
KEF |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
40-200 watts |
10-100 watts |
| Sensitivity |
88 dB |
86 dB |
| Impedance |
4 ohms |
8 ohms |
| Impedance |
n/a |
3.7 ohms |
| Frequency Response |
33-40 kHz |
51-28k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6" |
5.25" |
| Woofer Composition |
paper |
Aluminum |
| Woofer Surround Material |
n/a |
Rubber |
| Tweeter Size |
0.74" |
1" |
| Tweeter Type |
aluminum waveguide |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2000Hz |
2500Hz |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
375.0mm (14.8") |
303.0mm (11.9") |
| Width |
180.0mm (7.1") |
180.0mm (7.1") |
| Depth |
245.0mm (9.6") |
278.0mm (10.9") |
| Weight |
7.30kg (16.1lbs) |
5.60kg (12.3lbs) |
| Enclosure |
Passive Radiator |
Bass Reflex |
| Finish |
n/a |
MDF/Vinyl-wrapped |
| Available Colors |
Black, White, Walnut,Graphite Oak |
Black, Walnut, White |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
n/a |
18-24" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
n/a |
No |
Other |
|
|
| Parts Warranty |
|
5 Years |
| Labor Warranty |
|
5 Years |
No single best speaker here - they are built to different priorities, and the right one depends on your room, your amplifier and what you listen to.
| Area | Better | Why |
|---|
| Bass | A | Buchardt S400 digs deeper - 33Hz against 51Hz. |
| Amplifier needs | A | Buchardt S400 is more sensitive (88dB vs 86dB), so it goes louder on the same amplifier. |
| Amplifier match | B | KEF Q150 is the easier load at 8 ohms; the other is 4 ohms and wants an amplifier rated for it. |
| Headroom | A | Buchardt S400 takes more power (200W vs 100W) - more in hand in a big room. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Cabinet | depends | Passive Radiator vs Ported. |
A Buchardt S400 B KEF Q150
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Buchardt S400 has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 51Hz anyway, so judge these on the other rows instead. Match it to your room: we rate Buchardt S400 the better fit for a mid-size room and a large room, and KEF Q150 for near-field listening and a small room.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.