In this review, we will be comparing Q150 and 705 S2, two Passive Bookshelf speakers from KEF and Bowers Wilkins.
Let's have a brief look at the main features
of KEF Q150 and B&W 705 S2 first before getting into our more
detailed comparison.
| Key Specs | KEF Q150 | B&W 705 S2 |
|---|
| Brand | KEF
United Kingdom · founded 1961 | Bowers Wilkins
United Kingdom · founded 1966 |
|---|
| Design | 2-way | 2-way |
|---|
| Uni-Q driver | 11th Generation Uni-Q | — |
|---|
| Tweeter | 1" Dome | 1" Solid Body Soft-Dome |
|---|
| Woofer | 5.25" Aluminum | 6.5" Continuum |
|---|
| Frequency response | 51-28k Hz | 50-28k Hz |
|---|
| Sensitivity | 86 dB | 88 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 10-100 watts | 30-120 watts |
|---|
| Weight | 5.60kg / 12.3lbs | 9.32kg / 20.5lbs |
|---|
| Dimensions (H x W x D) | 11.9" x 7.0" x 10.9"
303.0 x 180.0 x 278.0mm | 16" x 7.8" x 11.9"
407.0 x 200.0 x 301.0mm |
|---|
What size room are the KEF Q150 and B&W 705 S2 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* |
KEF Q150 |
B&W 705 S2 |
| 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 Q150 and 705 S2 are 2-way speakers.
KEF Q150B&W 705 S2
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
KEF Q150 |
B&W 705 S2 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 6.5-inch
|
Q150 features a 1" vented aluminum Dome Tweeter and 1 x 5.25" Aluminum Woofer with a Crossover frequency at 2500Hz. On the other hand, the 705 S2 features a 1" Solid Body Soft-Dome Tweeter and 1 x 6.5" Continuum Woofer.
Frequency Response
Q150 has a frequency range of 51-28k Hz whereas 705 S2 has a frequency range of 50-28k Hz. With a minimum frequency of 50Hz, the 705 S2 can go slightly deeper then 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
Q150 and 705 S2 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. Q150 sensitivity is rated at 86 dB and the 705 S2's is at 88 dB. This 2 dB difference makes the B&W 705 S2 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.
705 S2 can handle a max power of 120 watts RMS, whereas Q150 has a max power handling value of 100 watts RMS, 20 watts less than the 705 S2.
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
705 S2 features Binding post posts which make bi-amping or bi-wiring possible. Q150 has a Post which doesn't feature bi-amping/bi-wiring.
KEF Q150's Post terminals
Cabinet Type and Port Position
Both Q150 and 705 S2 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.
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 KEF Q150's and B&W 705 S2's external dimensions. KEF Q150 has external dimensions of 303.0 x 180.0 x 278.0mm (11.9 x 7.0 x 10.9inch) whereas 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).
B&W 705 S2 is clearly the larger of the two speakers. Its body is 20mm wider, 104mm taller and 23mm deeper than KEF Q150.
Size, drawn to scale
Both speakers and both views share one scale, so everything here is directly comparable. Hover a box for its dimensions.
One scale for both, standing on the same surface and pushed back to the same wall, so the deeper one visibly sticks out further.
B&W 705 S2 needs about 20% more floor or shelf area. B&W 705 S2 is 23mm deeper, so it stands that much further out from the wall. B&W 705 S2 is 104mm taller.
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 KEF Q150 is approximately 500.4cm2 / 77.6inch2 and base area of the B&W 705 S2 is approximately 602.0cm2 / 93.3inch2. The Q150 requires 17% less surface area than the 705 S2 which gives it a small advantage 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 KEF Q150 weighs 5.60kg / 12.3lbs and the B&W 705 S2 weighs 9.32kg / 20.5lbs. This makes the 705 S2 66% heavier than the Q150.
Here is a comparison of how Q150 and 705 S2'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 are included inside the box of Q150:
- 2 Bookshelf loudspeakers
- 2 Foam port plugs
- 8 Self-adhesive rubber feet
- Owner's Manual
- Warranty Registration Card
What's in the Box of B&W 705 S2?
Here are the items that come with the 705 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
 Minimum Impedance |
3.7 ohms
vs
3.1 ohms
|
Very low impedance levels puts more pressure on amplifier |
 Height |
303mm
vs
407mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
500cm2
vs
602cm2
|
Takes less floor space |
 Price per pair* |
600USD
vs
3299USD
|
costs less (*prices may change depending on the seller, location and time) |
 Max Input Power |
120 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 |
6.5 inches
vs
5.25 inches
|
Larger woofer |
|
Low Frequency Response |
50 Hz
vs
51 Hz
|
Generates deeper bass |
 Bi-Amping and Bi-Wiring |
Yes
vs
No
|
Allows bi-amping and bi-wiring connections |
| General |
KEF Q150 |
Bowers & Wilkins 705 S2 |
| Brand |
KEF |
Bowers Wilkins |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
10-100 watts |
30-120 watts |
| Sensitivity |
86 dB |
88 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
3.7 ohms |
3.1 ohms |
| Frequency Response |
51-28k Hz |
50-28k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
6.5" |
| Woofer Composition |
Aluminum |
Continuum |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Dome |
Solid Body Soft-Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2500Hz |
n/a |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
303.0mm (11.9") |
407.0mm (16") |
| Width |
180.0mm (7.1") |
200.0mm (7.9") |
| Depth |
278.0mm (10.9") |
301.0mm (11.9") |
| Weight |
5.60kg (12.3lbs) |
9.32kg (20.5lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Vinyl-wrapped |
MDF/Wood veneer |
| Available Colors |
Black, Walnut, White |
Rosewood, Gloss Black, Satin White |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
18-24" |
24-26" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
Yes |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
These sit in different price classes - B&W 705 S2 costs roughly 5.5x what KEF Q150 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 | evenly matched | Much the same reach (51Hz vs 50Hz). |
| Amplifier needs | B | B&W 705 S2 is more sensitive (88dB vs 86dB), so it goes louder on the same amplifier. |
| Headroom | evenly matched | Similar power handling (100W vs 120W). |
| Size | depends | KEF Q150 is easier to place; B&W 705 S2 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | B | B&W 705 S2: bi-amping. |
| Price | A | KEF Q150 is cheaper - $600 against $3,299, about 82% less; arguably a different class. |
A KEF Q150 B B&W 705 S2
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?
The usual trade-off: B&W 705 S2 measures better, KEF Q150 costs about about 5.5x the price% less. Whether that gap is worth the money is the call only you can make - and in a normal room it is often smaller than the numbers suggest. Match it to your room: we rate KEF Q150 the better fit for near-field listening and a small room, and B&W 705 S2 for a mid-size room and a large room. In a large or open-plan room, B&W 705 S2 has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, KEF Q150 is the easier speaker to get right.
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.