In this review, we will be comparing Uni-Fi BS U5 Slim and RP-400M, two Passive Bookshelf speakers from ELAC and Klipsch.
Let's have a brief look at the main features
of ELAC Uni-Fi BS U5 Slim and Klipsch RP-400M first before getting into our more
detailed comparison.
| Key Specs | ELAC Uni-Fi BS U5 Slim | Klipsch RP-400M |
|---|
| Brand | ELAC
Germany · founded 1926 | Klipsch
United States · founded 1946 |
|---|
| Design | 3-way | 2-way |
|---|
| Tweeter | 1" soft dome | 1" Tractrix Horn |
|---|
| Midrange | 4" | — |
|---|
| Woofer | 5.25" Aluminum | 4" Cerametallic |
|---|
| Frequency response | 46-25k Hz | 52-25k Hz |
|---|
| Sensitivity | 85 dB | 93 dB |
|---|
| Impedance | 4 ohms | 8 ohms |
|---|
| Power range | 40-140 watts | up to 50 watts |
|---|
| Weight | 7.50kg / 16.5lbs | 4.10kg / 9lbs |
|---|
| Dimensions (H x W x D) | 13-3/8" x 7-1/16" x 12-7/8"
340.0 x 180.0 x 328.0mm | 11.7" x 5.6" x 7.5"
298.0 x 144.0 x 191.0mm |
|---|
What size room are the ELAC Uni-Fi BS U5 Slim and Klipsch RP-400M 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* |
ELAC Uni-Fi BS U5 Slim |
Klipsch RP-400M |
| Near-field |
Poor |
Good |
| Small Room |
Average |
Good |
| Mid-size Room |
Good |
Average |
| Large Room |
Average |
Poor |
| 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 Uni-Fi BS U5 Slim is a 3-way design whereas the RP-400M 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.
ELAC Uni-Fi BS U5 SlimKlipsch RP-400M
TweeterMidrangeWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
ELAC Uni-Fi BS U5 Slim |
Klipsch RP-400M |
|
Driver Setup
|
3-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
1 x 4-inch |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 4-inch
|
Uni-Fi BS U5 Slim features a 1" soft dome Tweeter, a 4" Midrange and 1 x 5.25" Aluminum Woofer. On the other hand, the RP-400M features a 1" Tractrix Horn Tweeter and 1 x 4" Cerametallic Woofer with a Crossover frequency at 1500Hz.
Frequency Response
Uni-Fi BS U5 Slim has a frequency range of 46-25k Hz whereas RP-400M has a frequency range of 52-25k Hz. With a minimum frequency of 46Hz, the Uni-Fi BS U5 Slim can go significantly deeper on the low side and provide stronger bass compared to the RP-400M's min frequency of 52Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf 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
Uni-Fi BS U5 Slim is a 4 ohms speaker compared to the RP-400M which has a nominal impedance of 8 ohms. Lower impedance speakers, especially the ones that are rated at 4 ohms may put more pressure on the amplifier unit especially when played at high volume levels, so make sure the amp you pair with the Uni-Fi BS U5 Slim can provide this impedance level.
These two speakers also have different sensitivity levels. Uni-Fi BS U5 Slim sensitivity is rated at 85 dB and the RP-400M's is rated at 93 dB. This 8 dB difference makes the Klipsch RP-400M a more sensitive speaker compared to ELAC Uni-Fi BS U5 Slim, hence will play louder with the same amount of watts.
Sensitivity
Bookshelf 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.
Uni-Fi BS U5 Slim can handle a max power of 140 watts RMS, whereas RP-400M has a max power handling value of 50 watts RMS, 90 watts less than the Uni-Fi BS U5 Slim.
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
Uni-Fi BS U5 Slim features Single binding posts type posts and RP-400M has a Single binding posts type posts. None of these speakers feature bi-amping/bi-wiring.
ELAC Uni-Fi BS U5 Slim's Post terminals
Klipsch RP-400M's Single binding posts terminals
Cabinet Type and Port Position
Both Uni-Fi BS U5 Slim and RP-400M 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.
Klipsch RP-400M Tractrix horn-shaped 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 ELAC Uni-Fi BS U5 Slim's and Klipsch RP-400M's external dimensions. ELAC Uni-Fi BS U5 Slim has external dimensions of 340.0 x 180.0 x 328.0mm (13-3/8 x 7-1/16 x 12-7/8inch) whereas Klipsch RP-400M has external dimensions of 298.0 x 144.0 x 191.0mm (11.7 x 5.6 x 7.5inch).
ELAC Uni-Fi BS U5 Slim is clearly the larger of the two speakers. Its body is 36mm wider, 42mm taller and 137mm deeper than Klipsch RP-400M.
Below you can see the front view size comparison of ELAC Uni-Fi BS U5 Slim and Klipsch RP-400M in scale.
Comparison image of ELAC Uni-Fi BS U5 Slim and Klipsch RP-400M Size and External Dimensions
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 ELAC Uni-Fi BS U5 Slim is approximately 590.4cm2 / 91.5inch2 and base area of the Klipsch RP-400M is approximately 275.0cm2 / 42.6inch2. The Uni-Fi BS U5 Slim requires 115% more surface area than the RP-400M which gives it a small disadvantage on placement in tight spaces.
Here is another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:
Size Comparison image of ELAC Uni-Fi BS U5 Slim and Klipsch RP-400M on a Media Console
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 ELAC Uni-Fi BS U5 Slim weighs 7.50kg / 16.5lbs and the Klipsch RP-400M weighs 4.10kg / 9lbs. This makes the Uni-Fi BS U5 Slim 83% heavier than the RP-400M.
Here is a comparison of how Uni-Fi BS U5 Slim and RP-400M's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of ELAC Uni-Fi BS U5 Slim?
Here are the items that are included inside the box of Uni-Fi BS U5 Slim:
- 2 Bookshelf loudspeakers
- 2 Grilles
- Operating Instructions
What's in the Box of Klipsch RP-400M?
Here are the items that come with the RP-400M:
- 2 Bookshelf loudspeakers
- 2 Grilles (installed)
- 8 Self-adhesive rubber feet
- User Manual
- Important Safety Instructions
- Warranty Information
 Max Input Power |
140 watts
vs
50 watts
|
Handle more power from your amplifier |
 Driver Setup |
3-way
vs
2-way
|
Have a dedicated mid-range driver |
 Woofer Size |
5.25 inches
vs
4 inches
|
Larger woofer |
|
Low Frequency Response |
46 Hz
vs
52 Hz
|
Generates deeper bass |
 Sensitivity |
93 dB
vs
85 dB
|
Play louder with same amount of amplification power |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
 Mounting Bracket |
Yes
vs
No
|
Allows mounting on walls |
 Height |
298mm
vs
340mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
275cm2
vs
590cm2
|
Takes less floor space |
 Price per pair* |
399USD
vs
735USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
ELAC Uni-Fi BS U5 Slim |
Klipsch Reference Premiere RP-400M |
| Brand |
ELAC |
Klipsch |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
40-140 watts |
up to 50 watts |
| Sensitivity |
85 dB |
93 dB |
| Impedance |
4 ohms |
8 ohms |
| Frequency Response |
46-25k Hz |
52-25k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
4" |
| Woofer Composition |
Aluminum |
Cerametallic |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
soft dome |
Tractrix Horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
4" |
No |
| Crossover Frequency |
n/a |
1500Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
340.0mm (13.4") |
298.0mm (11.7") |
| Width |
180.0mm (7.1") |
144.0mm (5.7") |
| Depth |
328.0mm (12.9") |
191.0mm (7.5") |
| Weight |
7.50kg (16.5lbs) |
4.10kg (9lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Vinyl |
MDF/Wood-grain vinyl |
| Available Colors |
Black |
Ebony, Walnut, Piano Black |
| Mounting Bracket |
No |
Keyhole |
| Recommended Stand Height |
24-31" |
28-30" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
3 Years |
5 Years |
| Labor Warranty |
3 Years |
5 Years |
These sit in different price classes - ELAC Uni-Fi BS U5 Slim costs roughly 1.8x what Klipsch RP-400M 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 | ELAC Uni-Fi BS U5 Slim digs deeper - 46Hz against 52Hz. A subwoofer would even that out. |
| Amplifier needs | B | Klipsch RP-400M is more sensitive (93dB vs 85dB), so it goes louder on the same amplifier. |
| Amplifier match | B | Klipsch RP-400M is the easier load at 8 ohms; the other is 4 ohms and wants an amplifier rated for it. |
| Headroom | A | ELAC Uni-Fi BS U5 Slim takes more power (140W vs 50W) - more in hand in a big room. |
| Size | depends | Klipsch RP-400M is easier to place; ELAC Uni-Fi BS U5 Slim 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-400M sits in a wider range (17 models), so a matched surround system is easier later. |
| Price | B | Klipsch RP-400M is cheaper - $399 against $735, about 46% less; arguably a different class. |
A ELAC Uni-Fi BS U5 Slim B Klipsch RP-400M
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. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 52Hz anyway, which makes the cheaper Klipsch RP-400M much easier to justify. Match it to your room: we rate ELAC Uni-Fi BS U5 Slim the better fit for a mid-size room and a large room, and Klipsch RP-400M for near-field listening and a small room.
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.