In this review, we will be comparing R400 and Apex A40, two Passive Center Channel speakers from Polk Audio and Monitor Audio.
Let's have a brief look at the main features
of Polk R400 and Monitor Audio Apex A40 first before getting into our more
detailed comparison.
| Key Specs | Polk R400 | Monitor Audio Apex A40 |
|---|
| Brand | Polk Audio
United States · founded 1972 | Monitor Audio
United Kingdom · founded 1972 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" Pinnacle Ring Radiator | 1" gold dome C-CAM |
|---|
| Woofer | 2 x 6.5" Polypropylene Turbine Cone | 2 x 5.5" C-CAM with RST® (Rigid Surface Technology) |
|---|
| Frequency response | 48-39K Hz | 50-35k Hz |
|---|
| Sensitivity | 89 dB | 90 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 20-200 watts | 50-200 watts |
|---|
| Weight | 14.91kg / 32.8lbs | 6.91kg / 15.2lbs |
|---|
| Dimensions (H x W x D) | 7-13/16" x 24-5/16" x 14-5/8"
199.0 x 618.0 x 372.0mm | 5-1/2" x 24" x 4-3/4"
140.0 x 610.0 x 121.0mm |
|---|
What size room are the Polk R400 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* |
Polk R400 |
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 R400 and Apex A40 are 2-way speakers.
Polk R400Monitor 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 |
Polk R400 |
Monitor Audio Apex A40 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
2 x 6.5-inch
|
2 x 5.5-inch
|
R400 features a 1" Pinnacle Ring Radiator Tweeter and 2 x 6.5" Polypropylene Turbine Cone Woofer with a Crossover frequency at 2500Hz. 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
R400 has a frequency range of 48-39K Hz whereas Apex A40 has a frequency range of 50-35k Hz. With a minimum frequency of 48Hz, the R400 can go slightly deeper then the Apex A40's min frequency of 50Hz.
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
R400 and Apex A40 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. R400 sensitivity is rated at 89 dB and the Apex A40's is at 90 dB. This 1 dB difference makes the Monitor Audio Apex A40 a more sensitive speaker compared to Polk R400, 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.
Both handle the same maximum of 200 watts RMS, though R400 is rated 20-200 watts and Apex A40 50-200 watts.
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
R400 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.
Polk R400's Binding post terminals
Polk R400 dual 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 R400's and Monitor Audio Apex A40's external dimensions. Polk R400 has external dimensions of 199.0 x 618.0 x 372.0mm (7-13/16 x 24-5/16 x 14-5/8inch) 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).
Polk R400 is clearly the larger of the two speakers. Its body is 8mm wider, 59mm taller and 251mm 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 Polk R400 is approximately 2299.0cm2 / 356.3inch2 and base area of the Monitor Audio Apex A40 is approximately 738.1cm2 / 114.4inch2. The R400 requires 211% 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 Polk R400 weighs 14.91kg / 32.8lbs and the Monitor Audio Apex A40 weighs 6.91kg / 15.2lbs. This makes the R400 116% heavier than the Apex A40.
Here is a comparison of how R400 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 Polk R400?
Here are the items that are included inside the box of R400:
- Center-channel loudspeaker
- Grille
- Owners Manual
- Online Registration
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
 Woofer Size |
6.5 inches
vs
5.5 inches
|
Larger woofer |
|
Low Frequency Response |
48 Hz
vs
50 Hz
|
Generates deeper bass |
 High Frequency Response |
39k Hz
vs
35k Hz
|
Generates higher frequency |
 Price per pair* |
649USD
vs
1125USD
|
costs less (*prices may change depending on the seller, location and time) |
 Sensitivity |
90 dB
vs
89 dB
|
Play louder with same amount of amplification power |
 Height |
140mm
vs
199mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
738cm2
vs
2299cm2
|
Takes less floor space |
| General |
Polk Audio Reserve R400 |
Monitor Audio Apex A40 |
| Brand |
Polk Audio |
Monitor Audio |
| Speaker Type |
Center channel speaker |
Center channel speaker |
| Power Range |
20-200 watts |
50-200 watts |
| Sensitivity |
89 dB |
90 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
4.1 ohms |
n/a |
| Frequency Response |
48-39K Hz |
50-35k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
6.5" |
5.5" |
| Woofer Composition |
Polypropylene Turbine Cone |
C-CAM with RST® (Rigid Surface Technology) |
| Woofer Surround Material |
Rubber |
n/a |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Pinnacle Ring Radiator |
gold dome C-CAM |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2500Hz |
n/a |
| Firing Direction |
rear |
n/a |
Physical Specs |
|
|
| Height |
199.0mm (7.8") |
140.0mm (5.5") |
| Width |
618.0mm (24.3") |
610.0mm (24") |
| Depth |
372.0mm (14.6") |
121.0mm (4.8") |
| Weight |
14.91kg (32.8lbs) |
6.91kg (15.2lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Available Colors |
Black, Walnut |
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 |
These sit in different price classes - Monitor Audio Apex A40 costs roughly 1.7x what Polk R400 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 | evenly matched | Much the same reach (48Hz vs 50Hz). |
| Amplifier needs | evenly matched | Similar sensitivity (89dB vs 90dB) - both want much the same power. |
| Headroom | evenly matched | Similar power handling (200W vs 200W). |
| Size | depends | Monitor Audio Apex A40 is easier to place; Polk R400 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | depends | Neither adds bi-amping, a sub output or height drivers. Polk R400 sits in a wider range (10 models), so a matched surround system is easier later. |
| Price | A | Polk R400 is cheaper - $649 against $1,125, about 42% less; arguably a different class. |
A Polk R400 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, Polk R400 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. Think about the whole system, not just the speakers: the roughly $476 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.