In this review, we will be comparing CSi A6 and RP-450C, two Passive Center Channel speakers from Polk Audio and Klipsch.
Let's have a brief look at the main features
of Polk CSi A6 and Klipsch RP-450C first before getting into our more
detailed comparison.
| Key Specs | Polk CSi A6 | Klipsch RP-450C |
|---|
| Brand | Polk Audio
United States · founded 1972 | Klipsch
United States · founded 1946 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" Dynamic Balance | 1" Tractrix horn |
|---|
| Woofer | 2 x 6.5" Dynamic Balance polymer composite | 4 x 5.25" Cerametallic cone |
|---|
| Frequency response | 55-26k Hz | 58-25k Hz |
|---|
| Sensitivity | 90 dB | 97 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 20-200 watts | up to 150 watts |
|---|
| Weight | 13.18kg / 29lbs | 16.23kg / 35.7lbs |
|---|
| Dimensions (H x W x D) | 7-13/16" x 24-1/16" x 14-1/4"
199.0 x 612.0 x 362.0mm | 6-13/16" x 31-1/8" x 14-9/16"
174.0 x 791.0 x 370.0mm |
|---|
What size room are the Polk CSi A6 and Klipsch RP-450C 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 CSi A6 |
Klipsch RP-450C |
| 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 CSi A6 and RP-450C are 2-way speakers.
Polk CSi A6Klipsch RP-450C
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Polk CSi A6 |
Klipsch RP-450C |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
2 x 6.5-inch
|
4 x 5.25-inch
|
CSi A6 features a 1" silk/polymer Dynamic Balance Tweeter and 2 x 6.5" Dynamic Balance polymer composite Woofer. On the other hand, the RP-450C features a 1" titanium Tractrix horn Tweeter and 4 x 5.25" Cerametallic cone Woofer.
Frequency Response
CSi A6 has a frequency range of 55-26k Hz whereas RP-450C has a frequency range of 58-25k Hz. With a minimum frequency of 55Hz, the CSi A6 can go slightly deeper then the RP-450C's min frequency of 58Hz.
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
CSi A6 and RP-450C have the same Impedance of 8 ohms but where they differ is the sensitivity levels. CSi A6 sensitivity is rated at 90 dB and the RP-450C's is at 97 dB. This 7 dB difference makes the Klipsch RP-450C a more sensitive speaker compared to Polk CSi A6, 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.
CSi A6 can handle a max power of 200 watts RMS, whereas RP-450C has a max power handling value of 150 watts RMS, 50 watts less than the CSi A6.
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
CSi A6 features Binding post type posts and RP-450C has a Binding post type posts. None of these speakers feature bi-amping/bi-wiring.
Polk CSi A6's 5-Way post terminals
Klipsch RP-450C's Binding post terminals
Cabinet Type and Port Position
Both CSi A6 and RP-450C 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.
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 CSi A6's and Klipsch RP-450C's external dimensions. Polk CSi A6 has external dimensions of 199.0 x 612.0 x 362.0mm (7-13/16 x 24-1/16 x 14-1/4inch) whereas Klipsch RP-450C has external dimensions of 174.0 x 791.0 x 370.0mm (6-13/16 x 31-1/8 x 14-9/16inch).
Polk CSi A6 is 179mm narrower and 8mm less deeper than Klipsch RP-450C but it is also 25mm 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 Polk CSi A6 is approximately 2215.4cm2 / 343.4inch2 and base area of the Klipsch RP-450C is approximately 2926.7cm2 / 453.6inch2. The CSi A6 requires 24% less surface area than the RP-450C 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 Polk CSi A6 weighs 13.18kg / 29lbs and the Klipsch RP-450C weighs 16.23kg / 35.7lbs. This makes the RP-450C 23% heavier than the CSi A6.
Here is a comparison of how CSi A6 and RP-450C'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 CSi A6?
Here are the items that are included inside the box of CSi A6:
- One cherry center channel speaker
- One 9.5-inch kickstand
- One 5.5-inch kickstand (installed)
- 4 Self-adhesive rubber feet
- Owners Manual
- Online registration sheet
- Polk Audio product brochure
What's in the Box of Klipsch RP-450C?
Here are the items that come with the RP-450C:
- Center-channel loudspeaker
- Detachable magnetic grille
- 4 Rubber feet
- User Manual
- Warranty Information
- Important Safety Instructions
 Max Input Power |
200 watts
vs
150 watts
|
Handle more power from your amplifier |
 Woofer Size |
6.5 inches
vs
5.25 inches
|
Larger woofer |
|
Low Frequency Response |
55 Hz
vs
58 Hz
|
Generates deeper bass |
 High Frequency Response |
26k Hz
vs
25k Hz
|
Generates higher frequency |
 Base Surface Area |
2215cm2
vs
2926cm2
|
Takes less floor space |
 Price per pair* |
399USD
vs
650USD
|
costs less (*prices may change depending on the seller, location and time) |
 Sensitivity |
97 dB
vs
90 dB
|
Play louder with same amount of amplification power |
|
Number of Woofers |
4
vs
2
|
More woofers |
 Height |
174mm
vs
199mm
|
Easier to fit in smaller spaces |
| General |
Polk Audio CSi A6 |
Klipsch Reference Premiere RP-450C |
| Brand |
Polk Audio |
Klipsch |
| Speaker Type |
Center channel speaker (Cherry) |
Center channel speaker (Ebony) |
| Power Range |
20-200 watts |
up to 150 watts |
| Sensitivity |
90 dB |
97 dB |
| Impedance |
8 ohms |
8 ohms |
| Frequency Response |
55-26k Hz |
58-25k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
4 |
| Woofer Size |
6.5" |
5.25" |
| Woofer Composition |
Dynamic Balance polymer composite |
Cerametallic cone |
| Woofer Surround Material |
n/a |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Dynamic Balance |
Tractrix horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
199.0mm (7.8") |
174.0mm (6.9") |
| Width |
612.0mm (24.1") |
791.0mm (31.1") |
| Depth |
362.0mm (14.3") |
370.0mm (14.6") |
| Weight |
13.18kg (29lbs) |
16.23kg (35.7lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
n/a |
polymer veneer |
| Available Colors |
Black, Cherry |
Walnut, Black |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
These sit in different price classes - Klipsch RP-450C costs roughly 1.6x what Polk CSi A6 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 | A | Polk CSi A6 digs deeper - 55Hz against 58Hz. A subwoofer would even that out. |
| Amplifier needs | B | Klipsch RP-450C is more sensitive (97dB vs 90dB), so it goes louder on the same amplifier. |
| Headroom | A | Polk CSi A6 takes more power (200W vs 150W) - more in hand in a big room. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Price | A | Polk CSi A6 is cheaper - $399 against $650, about 39% less; arguably a different class. |
A Polk CSi A6 B Klipsch RP-450C
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?
Polk CSi A6 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 your amplifier is modest, vintage or valve-based, Klipsch RP-450C is the safer partner - the other will want more current or more watts to sound its best. Think about the whole system, not just the speakers: the roughly $251 saved by taking the cheaper pair would buy a subwoofer or a better amplifier, and either usually does more for the sound than the difference between these two.
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.