In this review, we will be comparing Q650c and Ultra Center, two Passive Center Channel speakers from KEF and SVS.
Let's have a brief look at the main features
of KEF Q650c and SVS Ultra Center first before getting into our more
detailed comparison.
| Key Specs | KEF Q650c | SVS Ultra Center |
|---|
| Brand | KEF
United Kingdom · founded 1961 | SVS
United States · founded 1998 |
|---|
| Design | 2-way | 3-way |
|---|
| Uni-Q driver | 11th Generation Uni-Q | — |
|---|
| Tweeter | 1" Dome | 1" Dome |
|---|
| Midrange | — | 4" |
|---|
| Woofer | 2 x 6.5" aluminum | 2 x 6.5" composite glass-fiber |
|---|
| Frequency response | 64-28k Hz | 45-32k Hz |
|---|
| Sensitivity | 87 dB | 87 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 15-150 watts | 20-225 watts |
|---|
| Weight | 13.64kg / 30lbs | 14.09kg / 31lbs |
|---|
| Dimensions (H x W x D) | 8-5/16" x 24-13/16" x 11-15/16"
212.0 x 631.0 x 304.0mm | 8-1/8" x 22-1/16" x 11-3/16"
207.0 x 561.0 x 285.0mm |
|---|
What size room are the KEF Q650c and SVS Ultra Center 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 Q650c |
SVS Ultra Center |
| Near-field |
Poor |
Poor |
| Small Room |
Average |
Poor |
| Mid-size Room |
Good |
Good |
| Large Room |
Average |
Good |
| Very Large Room |
Poor |
Average |
(* 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
One of the fundamental differences between these two speakers is that Q650c is a 2-way design whereas the Ultra Center is a 3-way speaker. 3-way designs utilize a midrange driver in addition to the tweeter and woofer on 2-way designs. Designing a crossover for a 3-way speaker is a complicated process and generally increases the overall cost of the speaker.
KEF Q650cSVS Ultra Center
TweeterMidrangeWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
KEF Q650c |
SVS Ultra Center |
|
Driver Setup
|
2-way
|
3-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
1 x 4-inch |
|
Woofer
|
2 x 6.5-inch
|
2 x 6.5-inch
|
Q650c features a 1" vented aluminum Dome Tweeter and 2 x 6.5" aluminum Woofer with a Crossover frequency at 2500Hz. On the other hand, the Ultra Center features a 1" aluminum Dome Tweeter, a 4" Midrange and 2 x 6.5" composite glass-fiber Woofer with a Crossover frequency at 500Hz and 2200Hz.
Frequency Response
Q650c has a frequency range of 64-28k Hz whereas Ultra Center has a frequency range of 45-32k Hz. With a minimum frequency of 45Hz, the Ultra 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
Q650c and Ultra Center have the same Impedance of 8 ohms and their sensitivity is also same at 87 dB.
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.
Ultra Center can handle a max power of 225 watts RMS, whereas Q650c has a max power handling value of 150 watts RMS, 75 watts less than the Ultra 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
Ultra Center features 5-Way 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
SVS Ultra Center's 5-Way post terminals allows Bi-amping or bi-wiring
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 Q650c's and SVS Ultra Center's external dimensions. 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) whereas SVS Ultra Center has external dimensions of 207.0 x 561.0 x 285.0mm (8-1/8 x 22-1/16 x 11-3/16inch).
KEF Q650c is clearly the larger of the two speakers. Its body is 70mm wider, 5mm taller and 19mm deeper than SVS Ultra 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 20% more floor or shelf area. KEF Q650c is 19mm 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 KEF Q650c is approximately 1918.2cm2 / 297.3inch2 and base area of the SVS Ultra Center is approximately 1598.9cm2 / 247.8inch2. The Q650c requires 20% more surface area than the Ultra Center which gives it a small disadvantage 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 Q650c weighs 13.64kg / 30lbs and the SVS Ultra Center weighs 14.09kg / 31lbs. This makes the Ultra Center 3% heavier than the Q650c.
Here is a comparison of how Q650c and Ultra Center'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 are included inside the box of Q650c:
- Center-channel loudspeaker
- 4 Self-adhesive rubber feet
- Owners Manual
- Warranty Information
What's in the Box of SVS Ultra Center?
Here are the items that come with the Ultra Center:
- Center channel loudspeaker
- Grille
- 2 Terminal jumpers (pre-installed)
- 4 Rubber feet
- Owners Manual
- SVS brochure
- Online Product Registration Card
 Passive Radiator |
one 6.5-inch
vs
None
|
Increases the bass performance |
 Price per pair* |
750USD
vs
799USD
|
costs less (*prices may change depending on the seller, location and time) |
 Max Input Power |
225 watts
vs
150 watts
|
Handle more power from your amplifier |
 Driver Setup |
3-way
vs
2-way
|
Have a dedicated mid-range driver |
 Low Frequency Response |
45 Hz
vs
64 Hz
|
Generates deeper bass |
 High Frequency Response |
32k Hz
vs
28k Hz
|
Generates higher frequency |
 Height |
207mm
vs
212mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1598cm2
vs
1918cm2
|
Takes less floor space |
| General |
KEF Q650c |
SVS Ultra Center |
| Brand |
KEF |
SVS |
| Speaker Type |
Center channel speaker |
Center channel speaker |
| Power Range |
15-150 watts |
20-225 watts |
| Sensitivity |
87 dB |
87 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
4.2 ohms |
n/a |
| Frequency Response |
64-28k Hz |
45-32k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
6.5" |
6.5" |
| Woofer Composition |
aluminum |
composite glass-fiber |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
4" |
| Crossover Frequency |
2500Hz |
500Hz and 2200Hz |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
212.0mm (8.3") |
207.0mm (8.1") |
| Width |
631.0mm (24.8") |
561.0mm (22.1") |
| Depth |
304.0mm (12") |
285.0mm (11.2") |
| Weight |
13.64kg (30lbs) |
14.09kg (31lbs) |
| Enclosure |
Passive Radiator |
Bass Reflex |
| Available Colors |
Satin White, Satin Black, Walnut |
Black Oak,Piano Gloss Black,Piano Gloss White |
| Grille |
optional |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
n/a |
Yes |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
A generation apart: KEF Q650c is the newer design, against a 2013 model. Newer is not automatically better, but the older one is more likely to be discounted or near run-out.
| Area | Better | Why |
|---|
| Bass | B | SVS Ultra Center digs deeper - 45Hz against 64Hz. |
| Amplifier needs | evenly matched | Similar sensitivity (87dB vs 87dB) - both want much the same power. |
| Headroom | B | SVS Ultra Center takes more power (225W vs 150W) - more in hand in a big room. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Cabinet | depends | Passive Radiator vs Ported. |
| Expandability | B | SVS Ultra Center: bi-amping. |
| Price | evenly matched | Much the same money ($750 vs $799 a pair). |
A KEF Q650c B SVS Ultra Center
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?
SVS Ultra Center 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 64Hz anyway, so judge these on the other rows instead. Match it to your room: we rate KEF Q650c the better fit for a small room, and SVS Ultra Center for a large room and a very 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.