In this review, we will be comparing RP-504C II and Apex A40, two Passive Center Channel speakers from Klipsch and Monitor Audio.
Let's have a brief look at the main features
of Klipsch RP-504C II and Monitor Audio Apex A40 first before getting into our more
detailed comparison.
| Key Specs | Klipsch RP-504C II | Monitor Audio Apex A40 |
|---|
| Brand | Klipsch
United States · founded 1946 | Monitor Audio
United Kingdom · founded 1972 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" Tractrix Horn | 1" gold dome C-CAM |
|---|
| Woofer | 4 x 5.25" Cerametallic cone | 2 x 5.5" C-CAM with RST® (Rigid Surface Technology) |
|---|
| Frequency response | 50-25k Hz | 50-35k Hz |
|---|
| Sensitivity | 96 dB | 90 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | up to 150 watts | 50-200 watts |
|---|
| Weight | 16.50kg / 36.3lbs | 6.91kg / 15.2lbs |
|---|
| Dimensions (H x W x D) | 6-15/16" x 32-3/16" x 15-1/8"
177.0 x 818.0 x 385.0mm | 5-1/2" x 24" x 4-3/4"
140.0 x 610.0 x 121.0mm |
|---|
What size room are the Klipsch RP-504C II and Monitor Audio Apex A40 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* |
Klipsch RP-504C II |
Monitor Audio Apex A40 |
| 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 RP-504C II and Apex A40 are 2-way speakers.
Klipsch RP-504C IIMonitor Audio Apex A40
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Klipsch RP-504C II |
Monitor Audio Apex A40 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
4 x 5.25-inch
|
2 x 5.5-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 Apex A40 features a 1" gold dome C-CAM Tweeter and 2 x 5.5" C-CAM with RST® (Rigid Surface Technology) Woofer.
Frequency Response
RP-504C II has a frequency range of 50-25k Hz whereas Apex A40 has a frequency range of 50-35k Hz.
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
RP-504C II and Apex A40 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 Apex A40's is at 90 dB. This 6 dB difference makes the Klipsch RP-504C II a more sensitive speaker compared to Monitor Audio Apex A40, 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.
Apex A40 can handle a max power of 200 watts RMS, whereas RP-504C II has a max power handling value of 150 watts RMS, 50 watts less than the Apex A40.
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
RP-504C II features 5-Way post type posts and Apex A40 has a 5-Way post type posts. None of these speakers feature bi-amping/bi-wiring.
Klipsch RP-504C II'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 Klipsch RP-504C II's and Monitor Audio Apex A40'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 Monitor Audio Apex A40 has external dimensions of 140.0 x 610.0 x 121.0mm (5-1/2 x 24 x 4-3/4inch).
Klipsch RP-504C II is clearly the larger of the two speakers. Its body is 208mm wider, 37mm taller and 264mm deeper than Monitor Audio Apex A40.
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 Monitor Audio Apex A40 is approximately 738.1cm2 / 114.4inch2. The RP-504C II requires 327% more surface area than the Apex A40 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 Monitor Audio Apex A40 weighs 6.91kg / 15.2lbs. This makes the RP-504C II 139% heavier than the Apex A40.
Here is a comparison of how RP-504C II and Apex A40'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 loudspeaker
- Grille
- User Manual
- Important Safety Instructions
- Warranty Information
What's in the Box of Monitor Audio Apex A40?
Here are the items that come with the Apex A40:
- LCR loudspeaker
- Grille
- Bracket (pre-installed)
- 4 Self-adhesive rubber feet
- 2 Rubber inserts
- Hex-key
- Set Up Guide
- Important Safety Instructions
- Important Information
- Mounting Template
 Sensitivity |
96 dB
vs
90 dB
|
Play louder with same amount of amplification power |
 Number of Woofers |
4
vs
2
|
More woofers |
 Price per pair* |
799USD
vs
1125USD
|
costs less (*prices may change depending on the seller, location and time) |
 Max Input Power |
200 watts
vs
150 watts
|
Handle more power from your amplifier |
|
Woofer Size |
5.5 inches
vs
5.25 inches
|
Larger woofer |
 High Frequency Response |
35k Hz
vs
25k Hz
|
Generates higher frequency |
 Height |
140mm
vs
177mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
738cm2
vs
3149cm2
|
Takes less floor space |
| General |
Klipsch Reference Premiere RP-504C II |
Monitor Audio Apex A40 |
| Brand |
Klipsch |
Monitor Audio |
| Speaker Type |
Center channel speaker |
Center channel speaker |
| Power Range |
up to 150 watts |
50-200 watts |
| Sensitivity |
96 dB |
90 dB |
| Impedance |
8 ohms |
8 ohms |
| Frequency Response |
50-25k Hz |
50-35k Hz |
Drivers |
|
|
| Woofer Quantity |
4 |
2 |
| Woofer Size |
5.25" |
5.5" |
| Woofer Composition |
Cerametallic cone |
C-CAM with RST® (Rigid Surface Technology) |
| Woofer Surround Material |
Rubber |
n/a |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Tractrix Horn |
gold dome C-CAM |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
1950 Hz |
n/a |
| Firing Direction |
rear |
n/a |
Physical Specs |
|
|
| Height |
177.0mm (7") |
140.0mm (5.5") |
| Width |
818.0mm (32.2") |
610.0mm (24") |
| Depth |
385.0mm (15.2") |
121.0mm (4.8") |
| Weight |
16.50kg (36.3lbs) |
6.91kg (15.2lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Wood-grain vinyl |
n/a |
| Available Colors |
Walnut, Black |
Gloss White |
| 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 |
A generation apart: Klipsch RP-504C II is the newer design, against a 2011 model. Newer is not automatically better, but the older one is more likely to be discounted or near run-out.
| Area | Better | Why |
|---|
| Bass | evenly matched | Much the same reach (50Hz vs 50Hz). |
| Amplifier needs | A | Klipsch RP-504C II is more sensitive (96dB vs 90dB), so it goes louder on the same amplifier. |
| Headroom | B | Monitor Audio Apex A40 takes more power (200W vs 150W) - more in hand in a big room. |
| Size | depends | Monitor Audio Apex A40 is easier to place; Klipsch RP-504C II is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | depends | Neither adds bi-amping, a sub output or height drivers. Klipsch RP-504C II sits in a wider range (10 models), so a matched surround system is easier later. |
| Price | A | Klipsch RP-504C II is cheaper - $799 against $1,125, about 29% less. |
A Klipsch RP-504C II B Monitor Audio Apex A40
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and your own room settle it. In a large or open-plan room, Klipsch RP-504C II has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Monitor Audio Apex A40 is the easier speaker to get right. If your amplifier is modest, vintage or valve-based, Klipsch RP-504C II is the safer partner - the other will want more current or more watts to sound its best.
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.