In this review, we will be comparing Theva Center and Q650c, two Passive Center Channel speakers from Focal and KEF.
Let's have a brief look at the main features
of Focal Theva Center and KEF Q650c first before getting into our more
detailed comparison.
| Key Specs | Focal Theva Center | KEF Q650c |
|---|
| Brand | Focal
France · founded 1979 | KEF
United Kingdom · founded 1961 |
|---|
| Design | 2-way | 2-way |
|---|
| Uni-Q driver | — | 11th Generation Uni-Q |
|---|
| Tweeter | 1" inverted dome | 1" Dome |
|---|
| Woofer | 2 x 6.5" Slatefiber | 2 x 6.5" aluminum |
|---|
| Frequency response | 59-28kHz | 64-28k Hz |
|---|
| Sensitivity | 91 dB | 87 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 40-200 watts | 15-150 watts |
|---|
| Weight | 10.00kg / 22lbs | 13.64kg / 30lbs |
|---|
| Dimensions (H x W x D) | 8-1/4" x 20-7/8" x 10"
210.0 x 531.0 x 254.0mm | 8-5/16" x 24-13/16" x 11-15/16"
212.0 x 631.0 x 304.0mm |
|---|
What size room are the Focal Theva Center and KEF Q650c 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* |
Focal Theva Center |
KEF Q650c |
| Near-field |
Poor |
Poor |
| Small Room |
Average |
Average |
| Mid-size Room |
Good |
Good |
| Large Room |
Average |
Average |
| Very Large Room |
Poor |
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 Theva Center and Q650c are 2-way speakers.
Focal Theva CenterKEF Q650c
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 Theva Center |
KEF Q650c |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
2 x 6.5-inch
|
2 x 6.5-inch
|
Theva Center features a 1" TNF Al/Mg inverted dome Tweeter and 2 x 6.5" Slatefiber Woofer with a Crossover frequency at 2100 Hz. On the other hand, the Q650c features a 1" vented aluminum Dome Tweeter and 2 x 6.5" aluminum Woofer with a Crossover frequency at 2500Hz.
Frequency Response
Theva Center has a frequency range of 59-28kHz whereas Q650c has a frequency range of 64-28k Hz. With a minimum frequency of 59Hz, the Theva Center can go significantly deeper on the low side and provide stronger bass compared to the Q650c's min frequency of 64Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Center Channel class in our database.
Low Frequency
Center Channel 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
Theva Center and Q650c have the same Impedance of 8 ohms but where they differ is the sensitivity levels. Theva Center sensitivity is rated at 91 dB and the Q650c's is at 87 dB. This 4 dB difference makes the Focal Theva Center a more sensitive speaker compared to KEF Q650c, hence will play louder with the same amount of watts.
Sensitivity
Center Channel 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.
Theva Center can handle a max power of 200 watts RMS, whereas Q650c has a max power handling value of 150 watts RMS, 50 watts less than the Theva Center.
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
Theva Center features Binding post posts which make bi-amping or bi-wiring possible. Q650c has a Binding post which doesn't feature bi-amping/bi-wiring.
KEF Q650c's Binding post terminals
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 Theva Center's and KEF Q650c's external dimensions. Focal Theva Center has external dimensions of 210.0 x 531.0 x 254.0mm (81/4 x 207/8 x 10) whereas KEF Q650c has external dimensions of 212.0 x 631.0 x 304.0mm (8-5/16 x 24-13/16 x 11-15/16inch).
KEF Q650c is clearly the larger of the two speakers. Its body is 100mm wider, 2mm taller and 50mm deeper than Focal Theva Center.
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.
KEF Q650c needs about 42% more floor or shelf area. KEF Q650c is 50mm deeper, so it stands that much further out from the wall.
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 Theva Center is approximately 1348.7cm2 / 209.0inch2 and base area of the KEF Q650c is approximately 1918.2cm2 / 297.3inch2. The Theva Center requires 30% less surface area than the Q650c 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 Theva Center weighs 10.00kg / 22lbs and the KEF Q650c weighs 13.64kg / 30lbs. This makes the Q650c 36% heavier than the Theva Center.
Here is a comparison of how Theva Center and Q650c's weights compare with the average, max and min weights in Passive Center Channel class.
Weight
All Center Channel Speakers
What's in the Box of KEF Q650c?
Here are the items that come with the Q650c:
- Center-channel loudspeaker
- 4 Self-adhesive rubber feet
- Owners Manual
- Warranty Information
 Max Input Power |
200 watts
vs
150 watts
|
Handle more power from your amplifier |
 Sensitivity |
91 dB
vs
87 dB
|
Play louder with same amount of amplification power |
 Low Frequency Response |
59 Hz
vs
64 Hz
|
Generates deeper bass |
 Height |
210mm
vs
212mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1348cm2
vs
1918cm2
|
Takes less floor space |
 Price per pair* |
649USD
vs
750USD
|
costs less (*prices may change depending on the seller, location and time) |
 Minimum Impedance |
4.2 ohms
vs
3.8 ohms
|
Very low impedance levels puts more pressure on amplifier |
|
Passive Radiator |
one 6.5-inch
vs
None
|
Increases the bass performance |
| General |
Focal Theva Center |
KEF Q650c |
| Brand |
Focal |
KEF |
| Speaker Type |
Center channel speaker |
Center channel speaker |
| Power Range |
40-200 watts |
15-150 watts |
| Sensitivity |
91 dB |
87 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
3.8 ohms |
4.2 ohms |
| Frequency Response |
59-28kHz |
64-28k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
6.5" |
6.5" |
| Woofer Composition |
Slatefiber |
aluminum |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
inverted dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2100 Hz |
2500Hz |
Physical Specs |
|
|
| Height |
210.0mm (8.3") |
212.0mm (8.3") |
| Width |
531.0mm (20.9") |
631.0mm (24.8") |
| Depth |
254.0mm (10") |
304.0mm (12") |
| Weight |
10.00kg (22lbs) |
13.64kg (30lbs) |
| Enclosure |
Acoustic Suspension |
Passive Radiator |
| Available Colors |
Black High Gloss,Dark Wood,Light Wood |
Satin White, Satin Black, Walnut |
| Grille |
Yes |
optional |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
n/a |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
A generation apart: Focal Theva Center is the newer design, against a 2017 model. Newer is not automatically better, but the older one is more likely to be discounted or near run-out.
| Area | Better | Why |
|---|
| Bass | A | Focal Theva Center digs deeper - 59Hz against 64Hz. A subwoofer would even that out. |
| Amplifier needs | A | Focal Theva Center is more sensitive (91dB vs 87dB), so it goes louder on the same amplifier. |
| Headroom | A | Focal Theva Center takes more power (200W vs 150W) - more in hand in a big room. |
| Size | depends | Focal Theva Center is easier to place; KEF Q650c is bigger, which usually goes with fuller bass. Your room decides. |
| Cabinet | depends | Sealed vs Passive Radiator. Sealed is tighter and happier near a wall; ported digs lower but wants space behind it. |
| Expandability | A | Focal Theva Center: bi-amping. |
| Price | A | Focal Theva Center is cheaper - $649 against $750, about 13% less. |
A Focal Theva Center B KEF Q650c
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?
Focal Theva Center is the easier recommendation: it leads on most of the measured areas and costs less. Take KEF Q650c if its size, looks or fit in your room suit you better. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 64Hz anyway, so judge these on the other rows instead. In a large or open-plan room, KEF Q650c has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Focal Theva Center 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.