In this review, we will be comparing Sib Evo and R-51M, two Passive Bookshelf speakers from Focal and Klipsch.
Let's have a brief look at the main features
of Focal Sib Evo and Klipsch R-51M first before getting into our more
detailed comparison.
| Key Specs | Focal Sib Evo | Klipsch R-51M |
|---|
| Brand | Focal
France · founded 1979 | Klipsch
United States · founded 1946 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" Soft-Dome | 1" Tractrix Horn |
|---|
| Woofer | 5" Polyflex | 5.25" Copper-spun IMG |
|---|
| Frequency response | 70-25k Hz | 62-21k Hz |
|---|
| Sensitivity | 90 dB | 93 dB |
|---|
| Impedance | 6 ohms | 8 ohms |
|---|
| Power range | 25-200 watts | Up to 85 watts |
|---|
| Weight | 1.80kg / 4lbs | 5.00kg / 11lbs |
|---|
| Dimensions (H x W x D) | 9-7/8" x 6-3/8" x 6-7/16"
251.0 x 162.0 x 164.0mm | 13.3" x 7.0" x 8.4"
338.0 x 178.0 x 215.0mm |
|---|
What size room are the Focal Sib Evo and Klipsch R-51M 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* |
Focal Sib Evo |
Klipsch R-51M |
| Near-field |
Poor |
Average |
| Small Room |
Average |
Good |
| Mid-size Room |
Good |
Average |
| Large Room |
Average |
Poor |
| Very Large Room |
Poor |
Bad |
(* 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.
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through our links. As an Amazon Associate I earn from qualifying purchases.
Drivers
Both Sib Evo and R-51M are 2-way speakers.
Focal Sib EvoKlipsch R-51M
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Focal Sib Evo |
Klipsch R-51M |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5-inch
|
1 x 5.25-inch
|
Sib Evo features a 1" Soft-Dome Tweeter and 1 x 5" Polyflex Woofer. On the other hand, the R-51M features a 1" Tractrix Horn Tweeter and 1 x 5.25" Copper-spun IMG Woofer with a Crossover frequency at 1660Hz.
Frequency Response
Sib Evo has a frequency range of 70-25k Hz whereas R-51M has a frequency range of 62-21k Hz. With a minimum frequency of 62Hz, the R-51M can go significantly deeper on the low side and provide stronger bass compared to the Sib Evo's min frequency of 70Hz.
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
Sib Evo is a 6 ohms speaker compared to the R-51M which has a nominal impedance of 8 ohms.
These two speakers also have different sensitivity levels. Sib Evo sensitivity is rated at 90 dB and the R-51M's is rated at 93 dB. This 3 dB difference makes the Klipsch R-51M a more sensitive speaker compared to Focal Sib Evo, 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.
Sib Evo can handle a max power of 200 watts RMS, whereas R-51M has a max power handling value of 85 watts RMS, 115 watts less than the Sib Evo.
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
Sib Evo features Single Gold Plated Binding Posts - 5-way type posts and R-51M has a Single Gold Plated Binding Posts - 5-way type posts. None of these speakers feature bi-amping/bi-wiring.
Focal Sib Evo's Push button terminals
Klipsch R-51M's Single Gold Plated Binding Posts - 5-way terminals
Cabinet Type and Port Position
Both Sib Evo and R-51M 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.
New
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 Focal Sib Evo's and Klipsch R-51M's external dimensions. Focal Sib Evo has external dimensions of 251.0 x 162.0 x 164.0mm (28-36inch x 6-3/8inch x 6-7/16inch) whereas Klipsch R-51M has external dimensions of 338.0 x 178.0 x 215.0mm (13.3 x 7.0 x 8.4inch).
Klipsch R-51M is clearly the larger of the two speakers. Its body is 16mm wider, 87mm taller and 51mm deeper than Focal Sib Evo.
Below you can see the front view size comparison of Focal Sib Evo and Klipsch R-51M in scale.
Comparison image of Focal Sib Evo and Klipsch R-51M 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 Focal Sib Evo is approximately 265.7cm2 / 41.2inch2 and base area of the Klipsch R-51M is approximately 382.7cm2 / 59.3inch2. The Sib Evo requires 31% less surface area than the R-51M 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 Focal Sib Evo weighs 1.80kg / 4lbs and the Klipsch R-51M weighs 5.00kg / 11lbs. This makes the R-51M 178% heavier than the Sib Evo.
Here is a comparison of how Sib Evo and R-51M's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Focal Sib Evo?
Here are the items that are included inside the box of Sib Evo:
- 2 Satellite loudspeakers (base attached)
- 2 Wall-mount brackets
- 6 Screws
- 6 Wall-anchors
- User Manual
- Thank You card
What's in the Box of Klipsch R-51M?
Here are the items that come with the R-51M:
- 2 Bookshelf loudspeakers
- 2 Grilles (installed)
- 8 Self-adhesive rubber feet
- Quick Setup Guide
- Important Safety Instructions
- Warranty Information
 Max Input Power |
200 watts
vs
85 watts
|
Handle more power from your amplifier |
 High Frequency Response |
25k Hz
vs
21k Hz
|
Generates higher frequency |
 Mounting Bracket |
Yes
vs
No
|
Allows mounting on walls |
 Height |
251mm
vs
338mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
265cm2
vs
382cm2
|
Takes less floor space |
 Sensitivity |
93 dB
vs
90 dB
|
Play louder with same amount of amplification power |
 Nominal Impedance |
8 ohms
vs
6 ohms
|
Less selective with amplifiers |
 Woofer Size |
5.25 inches
vs
5 inches
|
Larger woofer |
|
Low Frequency Response |
62 Hz
vs
70 Hz
|
Generates deeper bass |
 Price per pair* |
359USD
vs
499USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Focal Sib Evo |
Klipsch Reference R-51M |
| Brand |
Focal |
Klipsch |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
25-200 watts |
Up to 85 watts |
| Sensitivity |
90 dB |
93 dB |
| Impedance |
6 ohms |
8 ohms |
| Frequency Response |
70-25k Hz |
62-21k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5" |
5.25" |
| Woofer Composition |
Polyflex |
Copper-spun IMG |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Soft-Dome |
Tractrix Horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
1660Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
251.0mm (9.9") |
338.0mm (13.3") |
| Width |
162.0mm (6.4") |
178.0mm (7") |
| Depth |
164.0mm (6.5") |
215.0mm (8.5") |
| Weight |
1.80kg (4lbs) |
5.00kg (11lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Lacquer |
MDF/Wood-grain vinyl |
| Available Colors |
Black |
Black |
| Mounting Bracket |
Yes |
No |
| Recommended Stand Height |
28-36" |
24-28" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
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 R-51M digs deeper - 62Hz against 70Hz. A subwoofer would even that out. |
| Amplifier needs | B | Klipsch R-51M is more sensitive (93dB vs 90dB), so it goes louder on the same amplifier. |
| Amplifier match | B | Klipsch R-51M is the easier load at 8 ohms. |
| Headroom | A | Focal Sib Evo takes more power (200W vs 85W) - more in hand in a big room. |
| Size | depends | Focal Sib Evo is easier to place; Klipsch R-51M is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | depends | Neither adds bi-amping, a sub output or height drivers. Klipsch R-51M sits in a wider range (5 models), so a matched surround system is easier later. |
| Price | B | Klipsch R-51M is cheaper - $359 against $499, about 28% less. |
A Focal Sib Evo B Klipsch R-51M
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 R-51M is the easier recommendation: it leads on most of the measured areas and costs less. Take Focal Sib Evo if its size, looks or fit in your room suit you better. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 70Hz anyway, so judge these on the other rows instead. Match it to your room: we rate Focal Sib Evo the better fit for a mid-size room and a large room, and Klipsch R-51M 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.