In this review, we will be comparing Sib-T and Q150, two Passive Bookshelf speakers from Focal and KEF.
Let's have a brief look at the main features
of Focal Sib-T and KEF Q150 first before getting into our more
detailed comparison.
| Key Specs | Focal Sib-T | KEF Q150 |
|---|
| Brand | Focal
France · founded 1979 | KEF
United Kingdom · founded 1961 |
|---|
| Design | 2-way | 2-way |
|---|
| Uni-Q driver | — | 11th Generation Uni-Q |
|---|
| Tweeter | .75" Dome | 1" Dome |
|---|
| Woofer | 5.125" Polyflex | 5.25" Aluminum |
|---|
| Frequency response | 80-20kHz | 51-28k Hz |
|---|
| Sensitivity | 90 dB | 86 dB |
|---|
| Impedance | 4 ohms | 8 ohms |
|---|
| Power range | — | 10-100 watts |
|---|
| Weight | 2.60kg / 5.7lbs | 5.60kg / 12.3lbs |
|---|
| Dimensions (H x W x D) | 2-1/2" x 5-5/8" x 6-11/16"
64.0 x 143.0 x 170.0mm | 11.9" x 7.0" x 10.9"
303.0 x 180.0 x 278.0mm |
|---|
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
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Drivers
Both Sib-T and Q150 are 2-way speakers.
Focal Sib-TKEF Q150
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Focal Sib-T |
KEF Q150 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
.75-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.125-inch
|
1 x 5.25-inch
|
Sib-T features a .75" Dome Tweeter and 1 x 5.125" Polyflex Woofer. On the other hand, the Q150 features a 1" vented aluminum Dome Tweeter and 1 x 5.25" Aluminum Woofer with a Crossover frequency at 2500Hz.
Frequency Response
Sib-T has a frequency range of 80-20kHz whereas Q150 has a frequency range of 51-28k Hz. With a minimum frequency of 51Hz, the Q150 can go significantly deeper on the low side and provide stronger bass compared to the Sib-T's min frequency of 80Hz.
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
Sib-T is a 4 ohms speaker compared to the Q150 which has a nominal impedance of 8 ohms. Lower impedance speakers, especially the ones that are rated at 4 ohms may put more pressure on the amplifier unit especially when played at high volume levels, so make sure the amp you pair with the Sib-T can provide this impedance level.
These two speakers also have different sensitivity levels. Sib-T sensitivity is rated at 90 dB and the Q150's is rated at 86 dB. This 4 dB difference makes the Focal Sib-T a more sensitive speaker compared to KEF Q150, hence will play louder with the same amount of watts.
Sensitivity
Bookshelf Speakers
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
Sib-T features Post type posts and Q150 has a Post type posts. None of these speakers feature bi-amping/bi-wiring.
Focal Sib-T's Spring posts terminals
KEF Q150's Post terminals
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 Focal Sib-T's and KEF Q150's external dimensions. Focal Sib-T has external dimensions of 64.0 x 143.0 x 170.0mm (2-1/2 x 5-5/8 x 6-11/16inch) whereas KEF Q150 has external dimensions of 303.0 x 180.0 x 278.0mm (11.9 x 7.0 x 10.9inch).
KEF Q150 is clearly the larger of the two speakers. Its body is 37mm wider, 239mm taller and 108mm deeper than Focal Sib-T.
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 Focal Sib-T is approximately 243.1cm2 / 37.7inch2 and base area of the KEF Q150 is approximately 500.4cm2 / 77.6inch2. The Sib-T requires 51% less surface area than the Q150 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 Focal Sib-T weighs 2.60kg / 5.7lbs and the KEF Q150 weighs 5.60kg / 12.3lbs. This makes the Q150 115% heavier than the Sib-T.
Here is a comparison of how Sib-T and Q150's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Focal Sib-T?
Here are the items that are included inside the box of Sib-T:
- One 100V/4-ohm commercial speaker
- Adjustable mounting bracket (installed)
- 3 Drywall anchors w/ 2 screws
- 5mm Allen key (attached to mounting bracket)
- User manual
What's in the Box of KEF Q150?
Here are the items that come with the Q150:
- 2 Bookshelf loudspeakers
- 2 Foam port plugs
- 8 Self-adhesive rubber feet
- Owner's Manual
- Warranty Registration Card
 Sensitivity |
90 dB
vs
86 dB
|
Play louder with same amount of amplification power |
 Mounting Bracket |
Yes
vs
No
|
Allows mounting on walls |
 Height |
64mm
vs
303mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
243cm2
vs
500cm2
|
Takes less floor space |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
 Woofer Size |
5.25 inches
vs
5.125 inches
|
Larger woofer |
|
Low Frequency Response |
51 Hz
vs
80 Hz
|
Generates deeper bass |
 High Frequency Response |
28k Hz
vs
20k Hz
|
Generates higher frequency |
 Price per pair* |
600USD
vs
698USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Focal Sib-T |
KEF Q150 |
| Brand |
Focal |
KEF |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Sensitivity |
90 dB |
86 dB |
| Impedance |
4 ohms |
8 ohms |
| Impedance |
n/a |
3.7 ohms |
| Frequency Response |
80-20kHz |
51-28k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.125" |
5.25" |
| Woofer Composition |
Polyflex |
Aluminum |
| Woofer Surround Material |
n/a |
Rubber |
| Tweeter Size |
.75" |
1" |
| Tweeter Type |
Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
2500Hz |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
64.0mm (2.5") |
303.0mm (11.9") |
| Width |
143.0mm (5.6") |
180.0mm (7.1") |
| Depth |
170.0mm (6.7") |
278.0mm (10.9") |
| Weight |
2.60kg (5.7lbs) |
5.60kg (12.3lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
Plastic |
MDF/Vinyl-wrapped |
| Available Colors |
White |
Black, Walnut, White |
| Mounting Bracket |
Yes |
No |
| Recommended Stand Height |
2-1/2" |
18-24" |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
No single best speaker here - they are built to different priorities, and the right one depends on your room, your amplifier and what you listen to.
| Area | Better | Why |
|---|
| Bass | B | KEF Q150 digs deeper - 51Hz against 80Hz. |
| Amplifier needs | A | Focal Sib-T is more sensitive (90dB vs 86dB), so it goes louder on the same amplifier. |
| Amplifier match | B | KEF Q150 is the easier load at 8 ohms; the other is 4 ohms and wants an amplifier rated for it. |
| Size | depends | Focal Sib-T is easier to place; KEF Q150 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | depends | Neither adds bi-amping, a sub output or height drivers. KEF Q150 sits in a wider range (7 models), so a matched surround system is easier later. |
| Price | B | KEF Q150 is cheaper - $600 against $698, about 14% less. |
A Focal Sib-T B KEF Q150
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?
KEF Q150 has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 80Hz anyway, so judge these on the other rows instead. In a large or open-plan room, KEF Q150 has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Focal Sib-T 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.