In this review, we will be comparing AE109 MII and RP-4000F, two Passive Floor-standing speakers from Acoustic Energy and Klipsch.
Let's have a brief look at the main features
of AE109 Mark II and Klipsch RP-4000F first before getting into our more
detailed comparison.
| Key Specs | AE109 Mark II | Klipsch RP-4000F |
|---|
| Brand | Acoustic Energy
United Kingdom · founded 1987 | Klipsch
United States · founded 1946 |
|---|
| Design | 3-way | 2-way |
|---|
| Tweeter | 1" dome with waveguide | 1" Tractrix Horn |
|---|
| Midrange | 5.2" | — |
|---|
| Woofer | 5.2" paper cone | 2 x 4" Cerametallic |
|---|
| Frequency response | 41Hz - 26kHz | 37-25k Hz |
|---|
| Sensitivity | 89 dB | 95 dB |
|---|
| Impedance | 6 ohms | 8 ohms |
|---|
| Power range | up to 175 watts | up to 75 watts |
|---|
| Weight | 16.00kg / 35.2lbs | 13.18kg / 29lbs |
|---|
| Dimensions (H x W x D) | 33.9" x 6.5" x 9.8"
860.0 x 165.0 x 250.0mm | 34-1/4" x 7-3/8" x 11-3/8"
870.0 x 188.0 x 289.0mm |
|---|
What size room are the AE109 Mark II and Klipsch RP-4000F 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* |
AE109 Mark II |
Klipsch RP-4000F |
| Near-field |
Bad |
Poor |
| Small Room |
Poor |
Average |
| Mid-size Room |
Good |
Good |
| Large Room |
Good |
Average |
| Very Large Room |
Poor |
No way |
(* 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
One of the fundamental differences between these two speakers is that AE109 MII is a 3-way design whereas the RP-4000F is a 2-way speaker. 3-way designs utilize a midrange driver in addition to the tweeter and woofer on 2-way designs. Designing a crossover for a 3-way speaker is a complicated process and generally increases the overall cost of the speaker.
AE109 Mark IIKlipsch RP-4000F
TweeterMidrangeWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
AE109 Mark II |
Klipsch RP-4000F |
|
Driver Setup
|
3-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
1 x 5.2-inch |
- |
|
Woofer
|
1 x 5.2-inch
|
2 x 4-inch
|
AE109 MII features a 1" fabric dome with waveguide Tweeter, a 5.2" Midrange and 1 x 5.2" paper cone Woofer with a Crossover frequency at 275Hz and 2.5kHz. On the other hand, the RP-4000F features a 1" Tractrix Horn Tweeter and 2 x 4" Cerametallic Woofer with a Crossover frequency at 1500 Hz.
Frequency Response
AE109 MII has a frequency range of 41Hz - 26kHz whereas RP-4000F has a frequency range of 37-25k Hz. With a minimum frequency of 37Hz, the RP-4000F can go slightly deeper then the AE109 MII's min frequency of 41Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Floor-standing class in our database.
Low Frequency
Floor-standing 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
AE109 MII is a 6 ohms speaker compared to the RP-4000F which has a nominal impedance of 8 ohms.
These two speakers also have different sensitivity levels. AE109 MII sensitivity is rated at 89 dB and the RP-4000F's is rated at 95 dB. This 6 dB difference makes the Klipsch RP-4000F a more sensitive speaker compared to AE109 Mark II, hence will play louder with the same amount of watts.
Sensitivity
Floor-standing 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.
AE109 MII can handle a max power of 175 watts RMS, whereas RP-4000F has a max power handling value of 75 watts RMS, 100 watts less than the AE109 MII.
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.
Cabinet Type and Port Position
Both AE109 MII and RP-4000F 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 AE109 Mark II's and Klipsch RP-4000F's external dimensions. AE109 Mark II has external dimensions of 860.0 x 165.0 x 250.0mm (33.9 x 6.5 x 9.8inch) whereas Klipsch RP-4000F has external dimensions of 870.0 x 188.0 x 289.0mm (34-1/4 x 7-3/8 x 11-3/8inch).
Klipsch RP-4000F is clearly the larger of the two speakers. Its body is 23mm wider, 10mm taller and 39mm deeper than AE109 Mark II.
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 AE109 Mark II is approximately 412.5cm2 / 63.9inch2 and base area of the Klipsch RP-4000F is approximately 543.3cm2 / 84.2inch2. The AE109 MII requires 24% less surface area than the RP-4000F 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 AE109 Mark II weighs 16.00kg / 35.2lbs and the Klipsch RP-4000F weighs 13.18kg / 29lbs. This makes the AE109 MII 21% heavier than the RP-4000F.
Here is a comparison of how AE109 MII and RP-4000F's weights compare with the average, max and min weights in Passive Floor-standing class.
Weight
All Floor-standing Speakers
What's in the Box of Klipsch RP-4000F?
Here are the items that come with the RP-4000F:
- Floorstanding loudspeaker
- Stabilizer feet (installed)
- Grille (installed)
- 2 Terminal jumpers (installed)
- User Manual
- Important Safety Instructions
- Warranty Information
 Max Input Power |
175 watts
vs
75 watts
|
Handle more power from your amplifier |
 Driver Setup |
3-way
vs
2-way
|
Have a dedicated mid-range driver |
 Woofer Size |
5.2 inches
vs
4 inches
|
Larger woofer |
 High Frequency Response |
26k Hz
vs
25k Hz
|
Generates higher frequency |
 Height |
860mm
vs
870mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
412cm2
vs
543cm2
|
Takes less floor space |
 Sensitivity |
95 dB
vs
89 dB
|
Play louder with same amount of amplification power |
 Nominal Impedance |
8 ohms
vs
6 ohms
|
Less selective with amplifiers |
|
Number of Woofers |
2
vs
1
|
More woofers |
|
Low Frequency Response |
37 Hz
vs
41 Hz
|
Generates deeper bass |
 Price per pair* |
698USD
vs
999USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Acoustic Energy AE109 Mark II |
Klipsch Reference Premiere RP-4000F |
| Brand |
Acoustic Energy |
Klipsch |
| Speaker Type |
Floor-standing speaker |
Floor-standing speaker |
| Power Range |
up to 175 watts |
up to 75 watts |
| Sensitivity |
89 dB |
95 dB |
| Impedance |
6 ohms |
8 ohms |
| Frequency Response |
41Hz - 26kHz |
37-25k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
2 |
| Woofer Size |
5.2" |
4" |
| Woofer Composition |
paper cone |
Cerametallic |
| Woofer Surround Material |
n/a |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
dome with waveguide |
Tractrix Horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
5.2" |
No |
| Crossover Frequency |
275Hz and 2.5kHz |
1500 Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
860.0mm (33.9") |
870.0mm (34.3") |
| Width |
165.0mm (6.5") |
188.0mm (7.4") |
| Depth |
250.0mm (9.8") |
289.0mm (11.4") |
| Weight |
16.00kg (35.2lbs) |
13.18kg (29lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
HDF |
MDF/Wood-grain vinyl |
| Available Colors |
Walnut, Satin Black |
Walnut, Black |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
n/a |
Yes |
Other |
|
|
| Parts Warranty |
|
5 Years |
| Labor Warranty |
|
5 Years |
No single best speaker here - they are built to different priorities, and the right one depends on your room, your amplifier and what you listen to.
| Area | Better | Why |
|---|
| Bass | B | Klipsch RP-4000F digs deeper - 37Hz against 41Hz. A subwoofer would even that out. |
| Amplifier needs | B | Klipsch RP-4000F is more sensitive (95dB vs 89dB), so it goes louder on the same amplifier. |
| Amplifier match | B | Klipsch RP-4000F is the easier load at 8 ohms. |
| Headroom | A | AE109 Mark II takes more power (175W vs 75W) - more in hand in a big room. |
| Size | depends | AE109 Mark II is easier to place; Klipsch RP-4000F is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | B | Klipsch RP-4000F: bi-amping. Klipsch RP-4000F sits in a wider range (17 models), so a matched surround system is easier later. |
| Price | B | Klipsch RP-4000F is cheaper - $698 against $999, about 30% less. |
A AE109 Mark II B Klipsch RP-4000F
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?
Klipsch RP-4000F is the easier recommendation: it leads on most of the measured areas and costs less. Take AE109 Mark II if its size, looks or fit in your room suit you better. Match it to your room: we rate AE109 Mark II the better fit for a large room, and Klipsch RP-4000F for a small room. If your amplifier is modest, vintage or valve-based, Klipsch RP-4000F 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.