In this review, we will be comparing 705 S2 and LS50, two Passive Bookshelf speakers from Bowers Wilkins and KEF. Let's have a brief look at the main features
of B&W 705 S2 and KEF LS50 first before getting into our more
detailed comparison.
What size room are the B&W 705 S2 and KEF LS50 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:
In the following sections, we will get into more detail in order to better understand how the B&W 705 S2 and KEF LS50 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
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Drivers
Both 705 S2 and LS50 are 2-way speakers.
| Driver |
B&W 705 S2 |
KEF LS50 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 6.5-inch
|
1 x 5.25-inch
|
705 S2 features a 1" Solid Body Soft-Dome Tweeter and 1 x 6.5" Continuum Woofer . On the other hand, the LS50 features a 1" Aluminum Vented dome Tweeter and 1 x 5.25" Magnesium/aluminum alloy Woofer with a Crossover frequency at 2200Hz.
Frequency Response
705 S2 has a frequency range of 50-28k Hz whereas LS50 has a frequency range of 79-28k Hz. With a minimum frequency of 50Hz, the 705 S2 can go significantly deeper on the low side and provide stronger bass compared to the LS50's min frequency of 79Hz.
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
High Frequency
Bookshelf Speakers
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
705 S2 and LS50 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. 705 S2 sensitivity is rated at 88 dB and the LS50's is at 85 dB. This 3 dB difference makes the B&W 705 S2 a more sensitive speaker compared to KEF LS50, 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. 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.
705 S2 can handle a max power of 120 watts RMS from the amp the whereas LS50 has a max power handling value of 100 watts RMS, 20 watts less than the 705 S2.
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.
Input Type and Bi-Amping / Bi-Wiring
705 S2 features Binding post posts which make bi-amping or bi-wiring possible. LS50 has a Post which doesn't feature bi-amping/bi-wiring.
KEF LS50's Post terminals
Cabinet Type and Port Position
Both 705 S2 and LS50 have rear firing ports. Rear ported speakers generally need more room between the backside of the speaker and the wall compared to sealed and front/bottom ported speakers. Placing the speakers too close to the walls may cause the bass to sound boomy.
If you are limited in space and can't get the speakers away from the backwall, check our Speakers with Front Firing Ports page.
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 B&W 705 S2's and KEF LS50's external dimensions. B&W 705 S2 has external dimensions of 407.0 x 200.0 x 301.0mm ( 16-inch x 7.8-inch x 11.9-inch) whereas KEF LS50 has external dimensions of 302.0 x 200.0 x 278.0mm ( 11.8 x 7.8 x 10.9inch) .
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 B&W 705 S2 is approximately 602.0cm2 / 93.3inch2 and base area of the KEF LS50 is approximately 556.0cm2 / 86.2inch2. The 705 S2 requires 8% more surface area than the LS50 which gives it a small disadvantage on placement in tight spaces.
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 B&W 705 S2 weighs 9.32kg / 20.5lbs and the KEF LS50 weighs 7.20kg / 15.8lbs. This makes the 705 S2 29% heavier than the LS50.
Here is a comparison of how 705 S2 and LS50's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of B&W 705 S2?
Here are the items that are included inside the box of 705 S2:
2 Bookshelf loudspeakers2 Grilles2 Two-piece foam port plugs8 Self-adhesive rubber feet4 Jumper-straps Manual Bowers & Wilkins brochureWarranty Information
What's in the Box of KEF LS50?
Here are the items that come with the LS50:
2 Bookshelf loudspeakers 2 Foam port plugs 8 Self-adhesive rubber feet Owner's Manual Warranty Registration Card
 Max Input Power |
120 watts
vs
100 watts
|
Handle more power from your amplifier |
 Sensitivity |
88 dB
vs
85 dB
|
Play louder with same amount of amplification power |
 Woofer Size |
6.5 inches
vs
5.25 inches
|
Larger woofer |
| Low Frequency Response |
50 Hz
vs
79 Hz
|
Generates deeper bass |
 Bi-Amping and Bi-Wiring |
Yes
vs
No
|
Allows bi-amping and bi-wiring connections |
 Minimum Impedance |
3.2 ohms
vs
3.1 ohms
|
Very low impedance levels puts more pressure on amplifier |
 Height |
302mm
vs
407mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
556cm2 (200x278mm)
vs
602cm2 (200x301mm)
|
Takes less floor space |
| General |
Bowers & Wilkins 705 S2 |
KEF LS50 |
| Brand |
Bowers Wilkins |
KEF |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
30-120 watts |
25-100 watts |
| Sensitivity |
88 dB |
85 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
3.1 ohms |
3.2 ohms |
| Frequency Response |
50-28k Hz |
79-28k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6.5" |
5.25" |
| Woofer Composition |
Continuum |
Magnesium/aluminum alloy |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Solid Body Soft-Dome |
Vented dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
2200Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
407.0mm (16") |
302.0mm (11.9") |
| Width |
200.0mm (7.9") |
200.0mm (7.9") |
| Depth |
301.0mm (11.9") |
278.0mm (10.9") |
| Weight |
9.32kg (20.5lbs) |
7.20kg (15.8lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Wood veneer |
Polymer/Lacquer |
| Available Colors |
Rosewood, Gloss Black, Satin White |
Black, High Gloss Piano Black, High Gloss Piano White |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
24-26" |
18-28" |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |