SpeakerDecision
  • SPEAKERS by TYPE
    • Passive Bookshelf Speakers
    • Passive Floor-standing Speakers
    • Passive Center Channel Speakers
    • Passive In-wall Speakers
    • All Passive Speakers
    • Powered Subwoofers
    • Powered Stereo Speakers
  • AMPLIFIERS
  • SMART FIND

Emotiva Airmotiv B2+ vs Buchardt S400 MKII Comparison

x
Speaker to replace
Change

Emotiva Airmotiv B2+

Passive Bookshelf | 40-28k Hz

Emotiva Airmotiv B2+
CHECK PRICE
Change
    
Buchardt S400 MKII

Passive Bookshelf | 33-40k HZ

Buchardt S400 MKII
CHECK PRICE
Emotiva Airmotiv B2+ Emotiva Airmotiv B2+
See at AMAZON
Buchardt S400 MKII Buchardt S400 MKII
See at AMAZON
Emotiva Airmotiv B2+
See at AMAZON
Buchardt S400 MKII
See at AMAZON
Emotiva Airmotiv B2+ vs Buchardt S400 MKII Speaker Comparison

In this review, we will be comparing Airmotiv B2+ and S400 MKII, two Passive Bookshelf speakers from Emotiva and Buchardt.

Let's have a brief look at the main features of Emotiva Airmotiv B2+ and Buchardt S400 MKII first before getting into our more detailed comparison.

Emotiva Airmotiv B2+ Key Specs

  • 2-way Design
  • 25×32 mm" folded ribbon Tweeter
  • 6.25" woven fiber cone Woofer
  • 40-28k Hz Frequency Response
  • 86 dB Sensitivity
  • Impedance: 4ohms
  • Power Range:Up to 125watts
  • Weight:7.10kg
  • Dimensions (H x W x D): 324.0" x 8-1/2" x 11-1/2"( 324.0 x 216.0 x 293.0mm )

Buchardt S400 MKII Key Specs

  • 2-way Design
  • 0.74" aluminum waveguide Tweeter
  • 6" paper Woofer
  • 33-40k HZ Frequency Response
  • 88 dB Sensitivity
  • Impedance: 4ohms
  • Power Range:40-200watts
  • Weight:7.50kg
  • Dimensions (H x W x D): 365.0" x 7" x 11"( 365.0 x 180.0 x 280.0mm )

What size room are the Emotiva Airmotiv B2+ and Buchardt S400 MKII 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* Emotiva Airmotiv B2+ Buchardt S400 MKII
Near-field Average Poor
Small Room Good Average
Mid-size Room Average Good
Large Room Poor Average
Very Large Room Bad Poor

(* 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.)

In the following sections, we will get into more detail in order to better understand how the Emotiva Airmotiv B2+ and Buchardt S400 MKII compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.


**This post contains affiliate links, and I will be compensated if you make a purchase after clicking through my links. As an Amazon Associate I earn from qualifying purchases.


Drivers

Both Airmotiv B2+ and S400 MKII are 2-way speakers.

Driver Emotiva Airmotiv B2+ Buchardt S400 MKII
Driver Setup 2-way 2-way
Tweeter 25×32 mm-inch 0.74-inch
Midrange - -
Woofer 1 x 6.25-inch 1 x 6-inch

Airmotiv B2+ features a 25×32 mm" folded ribbon Tweeter and 1 x 6.25" woven fiber cone Woofer with a Crossover frequency at 2000Hz. On the other hand, the S400 MKII features a 0.74" fine weave soft fabric textile aluminum waveguide Tweeter and 1 x 6" paper Woofer with a Crossover frequency at 1800Hz.

Frequency Response

Airmotiv B2+ has a frequency range of 40-28k Hz whereas S400 MKII has a frequency range of 33-40k HZ. With a minimum frequency of 33Hz, the S400 MKII can go significantly deeper on the low side and provide stronger bass compared to the Airmotiv B2+'s min frequency of 40Hz.

Below graphs depict how these two speakers compare with the max, min and average values of the Min and Max Frequencies of other speakers in the Bookshelf class in our database.

Low Frequency

Bookshelf Speakers

Airmotiv B2+
S400 MKII
Min
Average
Max
High Frequency

Bookshelf Speakers

Emotiva Airmotiv B2+
Buchardt S400 MKII
Min
Average
Max

None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.

Impedance and Sensitivity

Airmotiv B2+ and S400 MKII have the same Impedance of 4 ohms but where they differ is the sensitivity levels. Airmotiv B2+ sensitivity is rated at 86 dB and the S400 MKII's is at 88 dB. This 2 dB difference makes the Buchardt S400 MKII a more sensitive speaker compared to Emotiva Airmotiv B2+, hence will play louder with the same amount of watts.

One thing to keep in mind that the lower impedance speakers, especially the ones that are rated at 4 ohms may put more pressure on the amplifier unit comared to higher impedance speakers especially at high volume levels, so make sure the amp you pair with the Airmotiv B2+ and the Airmotiv B2+ can provide this impedance level.

Sensitivity

Bookshelf Speakers

Airmotiv B2+
S400 MKII
Min
Average
Max

Power Range

Power range is the range of input power in watts RMS that a loudspeaker is designed to handle. While using an amplifier within this range ensures the nominal performance , inputting a power that is higher than the max wattage can result in a damaged speaker.

Airmotiv B2+ can handle a max power of 200 watts RMS from the amp the whereas Airmotiv B2+ has a max power handling value of 125 watts RMS , 75 watts less than the S400 MKII.

Keep in mind that a higher max power handling value doesn't necessarily make that a louder speaker compared to a lower max handling speaker. Loudness or the sound level is also impacted by parameters such as Impedance, sensitivity and system efficiencies.

Emotiva Airmotiv B2+  Port
Emotiva Airmotiv B2+ Port

Physical Specs

Size of a speaker can sometimes become an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare Emotiva Airmotiv B2+'s and Buchardt S400 MKII's external dimensions. Emotiva Airmotiv B2+ has external dimensions of 324.0 x 216.0 x 293.0mm ( 12-3/4-inch x 8-1/2-inch x 11-1/2-inch) whereas Buchardt S400 MKII has external dimensions of 365.0 x 180.0 x 280.0mm ( 14.4 x 7 x 11inch) .

Buchardt S400 MKII is 36mm narrower and 13mm less deeper than Emotiva Airmotiv B2+ but it is also 41mm taller.

Below you can see the front view size comparison of Emotiva Airmotiv B2+ and Buchardt S400 MKII in scale.

Emotiva Airmotiv B2+ vs Buchardt S400 MKII Size Comparison - Front View
Comparison image of Emotiva Airmotiv B2+ and Buchardt S400 MKII 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 Emotiva Airmotiv B2+ is approximately 632.9cm2 / 98.1inch2 and base area of the Buchardt S400 MKII is approximately 504.0cm2 / 78.1inch2. The Airmotiv B2+ requires 26% more surface area than the S400 MKII which gives it a small disadvantage on placement in tight spaces.

Here is an another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:

Emotiva Airmotiv B2+ vs Buchardt S400 MKII Size Comparison on a Media Console
Size Comparison image of Emotiva Airmotiv B2+ and Buchardt S400 MKII 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 Emotiva Airmotiv B2+ weighs 7.10kg / 15.6lbs and the Buchardt S400 MKII weighs 7.50kg / 16.5lbs. This makes the S400 MKII 6% heavier than the Airmotiv B2+.

Here is a comparison of how Airmotiv B2+ and S400 MKII's weights compare with the average, max and min weights in Passive Bookshelf class.

Weight
All Bookshelf Speakers
Emotiva Airmotiv B2+
Buchardt S400 MKII
Min
Average
Max

Reasons to choose Emotiva Airmotiv B2+ over Buchardt S400 MKII
Woofer Size 6.25 inches vs 6 inches Larger woofer
Height 324mm vs 365mm Easier to fit in smaller spaces
Price per pair* 499USD vs 2200USD costs less (*prices may change depending on the seller, location and time)

Reasons to choose Buchardt S400 MKII over Emotiva Airmotiv B2+

Max Input Power 200 watts vs 125 watts Handle more power from your amplifier
Sensitivity 88 dB vs 86 dB Play louder with same amount of amplification power
Low Frequency Response 33 Hz vs 40 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 504cm2 vs 632cm2 Takes less floor space
Emotiva Airmotiv B2+ vs Buchardt S400 MKII Specs Table
Detailed comparison of specifications
General Emotiva Airmotiv B2+ Buchardt S400 MKII
Brand Emotiva Buchardt
Speaker Type Bookshelf speakers Bookshelf speakers
Power Range Up to 125 watts 40-200 watts
Sensitivity 86 dB 88 dB
Impedance 4 ohms 4 ohms
Frequency Response 40-28k Hz 33-40k HZ
Drivers
Woofer Quantity 1 1
Woofer Size 6.25" 6"
Woofer Composition woven fiber cone paper
Woofer Surround Material SBR n/a
Tweeter Size 25×32 mm" 0.74"
Tweeter Type folded ribbon aluminum waveguide
Aimable Tweeter No No
Midrange Driver No No
Crossover Frequency 2000Hz 1800Hz
Firing Direction rear n/a
Physical Specs
Height 324.0mm (12.8") 365.0mm (14.4")
Width 216.0mm (8.5") 180.0mm (7.1")
Depth 293.0mm (11.5") 280.0mm (11")
Weight 7.10kg (15.6lbs) 7.50kg (16.5lbs)
Enclosure Bass reflex Passive Radiator
Finish HDF n/a
Available Colors Black Black, White, Walnut, Rosewood, Light Oak
Mounting Bracket No No
Grille Yes Yes
Moisture Resistancy No No
Connections
Biamp Inputs Yes n/a
Other
Parts Warranty 5 Years 10 years
Labor Warranty 5 Years 10 years

Most Popular Speakers
Klipsch Reference R-51M
Klipsch R-51M
2-way | 93 dB | 8 ohms
ELAC Debut 2.0 B6.2
ELAC Debut 2.0 B6.2
2-way | 87 dB | 6 ohms
Wharfedale Elysian 2
Wharfedale Elysian 2
3-way | 89 dB | 4 ohms
KEF Q150
KEF Q150
2-way | 86 dB | 8 ohms
Bowers & Wilkins 606 S2 Anniversary Edition
B&W 606 S2
2-way | 88 dB | 8 ohms
Klipsch Reference Premiere RP-500M
Klipsch RP-500M
2-way | 93 dB | 8 ohms
Wharfedale EVO5.1
Wharfedale EVO5.1
2-way | 87 dB | 4 ohms
Wharfedale EVO4.1
Wharfedale EVO4.1
2-way | 87 dB | 8 ohms
Copyright © 2025 by SpeakerDecision
About Privacy Contact US Camera Decision

Report a Correction