In this review, we will be comparing RP-504C II and CSi A6, two Passive Center Channel speakers from Klipsch and Polk Audio. Let's have a brief look at the main features
of Klipsch RP-504C II and Polk CSi A6 first before getting into our more
detailed comparison.
What size room are the Klipsch RP-504C II and Polk CSi A6 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:
In the following sections, we will get into more detail in order to better understand how the Klipsch RP-504C II and Polk CSi A6 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
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Drivers
Both RP-504C II and CSi A6 are 2-way speakers.
| Driver |
Klipsch RP-504C II |
Polk CSi A6 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
4 x 5.25-inch
|
2 x 6.5-inch
|
RP-504C II features a 1" titanium Tractrix Horn Tweeter and 4 x 5.25" Cerametallic cone Woofer with a Crossover frequency at 1950 Hz. On the other hand, the CSi A6 features a 1" silk/polymer Dynamic Balance Tweeter and 2 x 6.5" Dynamic Balance polymer composite Woofer .
Frequency Response
RP-504C II has a frequency range of 50-25k Hz whereas CSi A6 has a frequency range of 55-26k Hz. With a minimum frequency of 50Hz, the RP-504C II can go significantly deeper on the low side and provide stronger bass compared to the CSi A6's min frequency of 55Hz.
Below graphs depict how these two speakers compare with the max, min and average values of the Min and Max Frequencies of other speakers in the Center Channel class in our database.
Low Frequency
Center Channel Speakers
High Frequency
Center Channel Speakers
None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
RP-504C II and CSi A6 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. RP-504C II sensitivity is rated at 96 dB and the CSi A6's is at 90 dB. This 6 dB difference makes the Klipsch RP-504C II 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. While using an amplifier within this range ensures the nominal performance , inputting a power that is higher than the max wattage can result in a damaged speaker.
RP-504C II can handle a max power of 200 watts RMS from the amp the whereas RP-504C II has a max power handling value of 150 watts RMS , 50 watts less than the CSi A6.
Keep in mind that a higher max power handling value doesn't necessarily make that a louder speaker
compared to a lower max handling speaker. Loudness or the sound level is also impacted by parameters
such as Impedance, sensitivity and system efficiencies.
Input Type and Bi-Amping / Bi-Wiring
RP-504C II features 5-Way post type posts and CSi A6 has a 5-Way post type posts. None of these speakers feature bi-amping/bi-wiring.
Klipsch RP-504C II's Binding post terminals
Polk CSi A6's 5-Way post terminals
Cabinet Type and Port Position
Both RP-504C II and CSi A6 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
Size of a speaker can sometimes become an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare Klipsch RP-504C II's and Polk CSi A6's external dimensions. Klipsch RP-504C II has external dimensions of 177.0 x 818.0 x 385.0mm ( 6-15/16 x 32-3/16 x 15-1/8inch) whereas 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) .
Polk CSi A6 is 206mm narrower and 23mm less deeper than Klipsch RP-504C II but it is also 22mm 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 Klipsch RP-504C II is approximately 3149.3cm2 / 488.1inch2 and base area of the Polk CSi A6 is approximately 2215.4cm2 / 343.4inch2. The RP-504C II requires 42% more surface area than the CSi A6 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 Klipsch RP-504C II weighs 16.50kg / 36.3lbs and the Polk CSi A6 weighs 13.18kg / 29lbs. This makes the RP-504C II 25% heavier than the CSi A6.
Here is a comparison of how RP-504C II and CSi A6'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 Klipsch RP-504C II?
Here are the items that are included inside the box of RP-504C II:
Center channel loudspeakerGrilleUser ManualImportant Safety InstructionsWarranty Information
What's in the Box of Polk CSi A6?
Here are the items that come with the CSi A6:
One cherry center channel speakerOne 9.5-inch kickstandOne 5.5-inch kickstand (installed)4 Self-adhesive rubber feetOwners ManualOnline registration sheetPolk Audio product brochure
 Sensitivity |
96 dB
vs
90 dB
|
Play louder with same amount of amplification power |
 Number of Woofers |
4
vs
2
|
More woofers |
| Low Frequency Response |
50 Hz
vs
55 Hz
|
Generates deeper bass |
 Height |
177mm
vs
199mm
|
Easier to fit in smaller spaces |
 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 |
 High Frequency Response |
26k Hz
vs
25k Hz
|
Generates higher frequency |
 Base Surface Area |
2215cm2 (612x362mm)
vs
3149cm2 (818x385mm)
|
Takes less floor space |
| General |
Klipsch Reference Premiere RP-504C II |
Polk Audio CSi A6 |
| Brand |
Klipsch |
Polk Audio |
| Speaker Type |
Center channel speaker |
Center channel speaker (Cherry) |
| Power Range |
up to 150 watts |
20-200 watts |
| Sensitivity |
96 dB |
90 dB |
| Impedance |
8 ohms |
8 ohms |
| Frequency Response |
50-25k Hz |
55-26k Hz |
Drivers |
|
|
| Woofer Quantity |
4 |
2 |
| Woofer Size |
5.25" |
6.5" |
| Woofer Composition |
Cerametallic cone |
Dynamic Balance polymer composite |
| Woofer Surround Material |
Rubber |
n/a |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Tractrix Horn |
Dynamic Balance |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
N/A" |
| Crossover Frequency |
1950 Hz |
n/a |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
177.0mm (7") |
199.0mm (7.8") |
| Width |
818.0mm (32.2") |
612.0mm (24.1") |
| Depth |
385.0mm (15.2") |
362.0mm (14.3") |
| Weight |
16.50kg (36.3lbs) |
13.18kg (29lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Wood-grain vinyl |
n/a |
| Available Colors |
Walnut, Black |
Black, Cherry |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
n/a |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |