In this review, we will be comparing 707 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 707 S2 and KEF LS50 first before getting into our more
detailed comparison.
What size room are the B&W 707 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 707 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 707 S2 and LS50 are 2-way speakers.
| Driver |
B&W 707 S2 |
KEF LS50 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5-inch
|
1 x 5.25-inch
|
707 S2 features a 1" Decoupled Soft-Dome Tweeter and 1 x 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
707 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 707 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
707 S2 and LS50 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. 707 S2 sensitivity is rated at 84 dB and the LS50's is at 85 dB. This 1 dB difference makes the KEF LS50 a more sensitive speaker compared to B&W 707 S2, 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.
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
707 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 707 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 707 S2's and KEF LS50's external dimensions. B&W 707 S2 has external dimensions of 280.0 x 165.0 x 276.0mm ( 11-inch x 6.5-inch x 10.9-inch) whereas KEF LS50 has external dimensions of 302.0 x 200.0 x 278.0mm ( 11.8 x 7.8 x 10.9inch) .
KEF LS50 is clearly the larger of the two speakers. Its body is 35mm wider, 22mm taller and 2mm deeper than B&W 707 S2.
Below you can see the front view size comparison of B&W 707 S2 and KEF LS50 in scale.
Comparison image of B&W 707 S2 and KEF LS50 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 B&W 707 S2 is approximately 455.4cm2 / 70.6inch2 and base area of the KEF LS50 is approximately 556.0cm2 / 86.2inch2. The 707 S2 requires 18% less surface area than the LS50 which gives it a small advantage 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:
Size Comparison image of B&W 707 S2 and KEF LS50 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 B&W 707 S2 weighs 6.00kg / 13.2lbs and the KEF LS50 weighs 7.20kg / 15.8lbs. This makes the LS50 20% heavier than the 707 S2.
Here is a comparison of how 707 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 707 S2?
Here are the items that are included inside the box of 707 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
 Minimum Impedance |
4.0 ohms
vs
3.2 ohms
|
Very low impedance levels puts more pressure on amplifier |
 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 |
 Height |
280mm
vs
302mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
455cm2 (165x276mm)
vs
556cm2 (200x278mm)
|
Takes less floor space |
 Sensitivity |
85 dB
vs
84 dB
|
Play louder with same amount of amplification power |
| Woofer Size |
5.25 inches
vs
5 inches
|
Larger woofer |
| General |
Bowers & Wilkins 707 S2 |
KEF LS50 |
| Brand |
Bowers Wilkins |
KEF |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
30-100 watts |
25-100 watts |
| Sensitivity |
84 dB |
85 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
4.0 ohms |
3.2 ohms |
| Frequency Response |
50-28k Hz |
79-28k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5" |
5.25" |
| Woofer Composition |
Continuum |
Magnesium/aluminum alloy |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Decoupled Soft-Dome |
Vented dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
2200Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
280.0mm (11") |
302.0mm (11.9") |
| Width |
165.0mm (6.5") |
200.0mm (7.9") |
| Depth |
276.0mm (10.9") |
278.0mm (10.9") |
| Weight |
6.00kg (13.2lbs) |
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 |