In this review, we will be comparing L400 and Ultra Center, two Passive Center Channel speakers from Polk Audio and SVS.
Let's have a brief look at the main features
of Polk L400 and SVS Ultra Center first before getting into our more
detailed comparison.
| Key Specs | Polk L400 | SVS Ultra Center |
|---|
| Brand | Polk Audio
United States · founded 1972 | SVS
United States · founded 1998 |
|---|
| Design | 3-way | 3-way |
|---|
| Tweeter | 1" Pinnacle Ring Radiator | 1" Dome |
|---|
| Midrange | 4" | 4" |
|---|
| Woofer | 2 x 6.5" | 2 x 6.5" composite glass-fiber |
|---|
| Frequency response | 55-38k Hz | 45-32k Hz |
|---|
| Sensitivity | 87.5 dB | 87 dB |
|---|
| Impedance | 4 ohms | 8 ohms |
|---|
| Power range | 25-300 watts | 20-225 watts |
|---|
| Weight | 18.55kg / 40.8lbs | 14.09kg / 31lbs |
|---|
| Dimensions (H x W x D) | 9-5/8" x 26-1/16" x 13-1/2"
245.0 x 662.0 x 343.0mm | 8-1/8" x 22-1/16" x 11-3/16"
207.0 x 561.0 x 285.0mm |
|---|
What size room are the Polk L400 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* |
Polk L400 |
SVS Ultra Center |
| Near-field |
Poor |
Poor |
| Small Room |
Poor |
Poor |
| Mid-size Room |
Good |
Good |
| Large Room |
Good |
Good |
| Very Large Room |
Average |
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
Both L400 and Ultra Center are 3-way speakers.
Polk L400SVS 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 |
Polk L400 |
SVS Ultra Center |
|
Driver Setup
|
3-way
|
3-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
1 x 4-inch |
1 x 4-inch |
|
Woofer
|
2 x 6.5-inch
|
2 x 6.5-inch
|
L400 features a 1" Pinnacle Ring Radiator Tweeter, a 4" Midrange and 2 x 6.5" Woofer. 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
L400 has a frequency range of 55-38k 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 L400's min frequency of 55Hz.
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
L400 is a 4 ohms speaker compared to the Ultra Center 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 L400 can provide this impedance level.
These two speakers also have different sensitivity levels. L400 sensitivity is rated at 87.5 dB and the Ultra Center's is rated at 87 dB. This 1 dB difference makes the Polk L400 a more sensitive speaker compared to SVS Ultra Center, 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.
L400 can handle a max power of 300 watts RMS, whereas Ultra Center has a max power handling value of 225 watts RMS, 75 watts less than the L400.
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. L400 has a Binding post which doesn't feature bi-amping/bi-wiring.
Polk L400's Binding post terminals
SVS Ultra Center's 5-Way post terminals allows Bi-amping or bi-wiring
Cabinet Type and Port Position
Both L400 and Ultra Center 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.
Polk L400 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 Polk L400's and SVS Ultra Center's external dimensions. Polk L400 has external dimensions of 245.0 x 662.0 x 343.0mm (9-5/8 x 26-1/16 x 13-1/2inch) 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).
Polk L400 is clearly the larger of the two speakers. Its body is 101mm wider, 38mm taller and 58mm deeper than SVS Ultra Center.
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 Polk L400 is approximately 2270.7cm2 / 352.0inch2 and base area of the SVS Ultra Center is approximately 1598.9cm2 / 247.8inch2. The L400 requires 42% 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 Polk L400 weighs 18.55kg / 40.8lbs and the SVS Ultra Center weighs 14.09kg / 31lbs. This makes the L400 32% heavier than the Ultra Center.
Here is a comparison of how L400 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 Polk L400?
Here are the items that are included inside the box of L400:
- Center-channel loudspeaker
- Grille
- 2 Jumper-wires
- Cleaning cloth
- Owners Manual
- Online Registration
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
 Max Input Power |
300 watts
vs
225 watts
|
Handle more power from your amplifier |
 Sensitivity |
88 dB
vs
87 dB
|
Play louder with same amount of amplification power |
 High Frequency Response |
38k Hz
vs
32k Hz
|
Generates higher frequency |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
 Low Frequency Response |
45 Hz
vs
55 Hz
|
Generates deeper bass |
 Height |
207mm
vs
245mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1598cm2
vs
2270cm2
|
Takes less floor space |
 Price per pair* |
799USD
vs
1799USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Polk Audio Legend L400 |
SVS Ultra Center |
| Brand |
Polk Audio |
SVS |
| Speaker Type |
Center channel speaker |
Center channel speaker |
| Power Range |
25-300 watts |
20-225 watts |
| Sensitivity |
87.5 dB |
87 dB |
| Impedance |
4 ohms |
8 ohms |
| Frequency Response |
55-38k Hz |
45-32k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
6.5" |
6.5" |
| Woofer Composition |
|
composite glass-fiber |
| Woofer Surround Material |
n/a |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Pinnacle Ring Radiator |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
4" |
4" |
| Crossover Frequency |
n/a |
500Hz and 2200Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
245.0mm (9.6") |
207.0mm (8.1") |
| Width |
662.0mm (26.1") |
561.0mm (22.1") |
| Depth |
343.0mm (13.5") |
285.0mm (11.2") |
| Weight |
18.55kg (40.8lbs) |
14.09kg (31lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Available Colors |
Black, Walnut |
Black Oak,Piano Gloss Black,Piano Gloss White |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
n/a |
Yes |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
These sit in different price classes - Polk L400 costs roughly 2.3x what SVS Ultra Center 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 | B | SVS Ultra Center digs deeper - 45Hz against 55Hz. |
| Amplifier needs | evenly matched | Similar sensitivity (88dB vs 87dB) - both want much the same power. |
| Amplifier match | B | SVS Ultra Center is the easier load at 8 ohms; the other is 4 ohms and wants an amplifier rated for it. |
| Headroom | A | Polk L400 takes more power (300W vs 225W) - more in hand in a big room. |
| Size | depends | SVS Ultra Center is easier to place; Polk L400 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | B | SVS Ultra Center: bi-amping. |
| Price | B | SVS Ultra Center is cheaper - $799 against $1,799, about 56% less; arguably a different class. |
A Polk L400 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 is the easier recommendation: it leads on most of the measured areas and costs less. Take Polk L400 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 55Hz anyway, so judge these on the other rows instead. In a large or open-plan room, Polk L400 has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, SVS Ultra 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.