In this review, we will be comparing 707 S2 and Q350, 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 Q350 first before getting into our more
detailed comparison.
| Key Specs | B&W 707 S2 | KEF Q350 |
|---|
| Brand | Bowers Wilkins
United Kingdom · founded 1966 | KEF
United Kingdom · founded 1961 |
|---|
| Design | 2-way | 2-way |
|---|
| Uni-Q driver | — | 11th Generation Uni-Q |
|---|
| Tweeter | 1" Decoupled Soft-Dome | 1" Dome |
|---|
| Woofer | 5" Continuum | 6.5" Aluminum |
|---|
| Frequency response | 50-28k Hz | 63-28k Hz |
|---|
| Sensitivity | 84 dB | 87 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 30-100 watts | 10-120 watts |
|---|
| Weight | 6.00kg / 13.2lbs | 7.60kg / 16.7lbs |
|---|
| Dimensions (H x W x D) | 11" x 6.5" x 10.9"
280.0 x 165.0 x 276.0mm | 14.0" x 8.2" x 12.0"
358.0 x 210.0 x 306.0mm |
|---|
What size room are the B&W 707 S2 and KEF Q350 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* |
B&W 707 S2 |
KEF Q350 |
| 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.)
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both 707 S2 and Q350 are 2-way speakers.
B&W 707 S2KEF Q350
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
B&W 707 S2 |
KEF Q350 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5-inch
|
1 x 6.5-inch
|
707 S2 features a 1" Decoupled Soft-Dome Tweeter and 1 x 5" Continuum Woofer. On the other hand, the Q350 features a 1" vented aluminum Dome Tweeter and 1 x 6.5" Aluminum Woofer with a Crossover frequency at 2500Hz.
Frequency Response
707 S2 has a frequency range of 50-28k Hz whereas Q350 has a frequency range of 63-28k 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 Q350's min frequency of 63Hz.
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
707 S2 and Q350 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 Q350's is at 87 dB. This 3 dB difference makes the KEF Q350 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. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
Q350 can handle a max power of 120 watts RMS, whereas 707 S2 has a max power handling value of 100 watts RMS, 20 watts less than the Q350.
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.
Input Type and Bi-Amping / Bi-Wiring
707 S2 features Binding post posts which make bi-amping or bi-wiring possible. Q350 has a Post which doesn't feature bi-amping/bi-wiring.
KEF Q350's Post terminals
Cabinet Type and Port Position
Both 707 S2 and Q350 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
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 B&W 707 S2's and KEF Q350'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 Q350 has external dimensions of 358.0 x 210.0 x 306.0mm (14.0 x 8.2 x 12.0inch).
KEF Q350 is clearly the larger of the two speakers. Its body is 45mm wider, 78mm taller and 30mm deeper than B&W 707 S2.
Below you can see the front view size comparison of B&W 707 S2 and KEF Q350 in scale.
Comparison image of B&W 707 S2 and KEF Q350 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 Q350 is approximately 642.6cm2 / 99.6inch2. The 707 S2 requires 29% less surface area than the Q350 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 B&W 707 S2 and KEF Q350 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 Q350 weighs 7.60kg / 16.7lbs. This makes the Q350 27% heavier than the 707 S2.
Here is a comparison of how 707 S2 and Q350'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 loudspeakers
- 2 Grilles
- 2 Two-piece foam port plugs
- 8 Self-adhesive rubber feet
- 4 Jumper-straps
- Manual
- Bowers & Wilkins brochure
- Warranty Information
What's in the Box of KEF Q350?
Here are the items that come with the Q350:
- 2 Bookshelf loudspeakers
- 2 Foam port plugs
- 8 Self-adhesive rubber feet
- Owner's Manual
- Warranty Registration Card
 Minimum Impedance |
4.0 ohms
vs
3.7 ohms
|
Very low impedance levels puts more pressure on amplifier |
 Low Frequency Response |
50 Hz
vs
63 Hz
|
Generates deeper bass |
 Bi-Amping and Bi-Wiring |
Yes
vs
No
|
Allows bi-amping and bi-wiring connections |
 Height |
280mm
vs
358mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
455cm2
vs
642cm2
|
Takes less floor space |
 Max Input Power |
120 watts
vs
100 watts
|
Handle more power from your amplifier |
 Sensitivity |
87 dB
vs
84 dB
|
Play louder with same amount of amplification power |
|
Woofer Size |
6.5 inches
vs
5 inches
|
Larger woofer |
 Price per pair* |
750USD
vs
1599USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Bowers & Wilkins 707 S2 |
KEF Q350 |
| Brand |
Bowers Wilkins |
KEF |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
30-100 watts |
10-120 watts |
| Sensitivity |
84 dB |
87 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
4.0 ohms |
3.7 ohms |
| Frequency Response |
50-28k Hz |
63-28k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5" |
6.5" |
| Woofer Composition |
Continuum |
Aluminum |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Decoupled Soft-Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
2500Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
280.0mm (11") |
358.0mm (14.1") |
| Width |
165.0mm (6.5") |
210.0mm (8.3") |
| Depth |
276.0mm (10.9") |
306.0mm (12") |
| Weight |
6.00kg (13.2lbs) |
7.60kg (16.7lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Wood Veneer |
MDF/Vinyl-wrapped |
| Available Colors |
Rosewood, Gloss Black, Satin White |
Black, Walnut, White |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
24-26" |
18-24" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
These sit in different price classes - B&W 707 S2 costs roughly 2.1x what KEF Q350 does. Expect it to lead on paper; the question is whether the gap is audible enough in your room to be worth it.
| Area | Better | Why |
|---|
| Bass | A | B&W 707 S2 digs deeper - 50Hz against 63Hz. |
| Amplifier needs | B | KEF Q350 is more sensitive (87dB vs 84dB), so it goes louder on the same amplifier. |
| Headroom | evenly matched | Similar power handling (100W vs 120W). |
| Size | depends | B&W 707 S2 is easier to place; KEF Q350 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | A | B&W 707 S2: bi-amping. |
| Price | B | KEF Q350 is cheaper - $750 against $1,599, about 53% less; arguably a different class. |
A B&W 707 S2 B KEF Q350
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?
B&W 707 S2 is ahead, but only on 1 of the measured areas, and it costs about 113% more. That is a lot of money for a narrow margin on paper - KEF Q350 looks like the sensible buy unless something else about the B&W 707 S2 appeals to you. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 63Hz anyway, which makes the cheaper KEF Q350 much easier to justify. Match it to your room: we rate B&W 707 S2 the better fit for near-field listening and a small room, and KEF Q350 for a mid-size room and a large 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.