In this review, we will be comparing Sib-T and R-51M, two Passive Bookshelf speakers from Focal and Klipsch. Let's have a brief look at the main features
of Focal Sib-T and Klipsch R-51M first before getting into our more
detailed comparison.
In the following sections, we will get into more detail in order to better understand how the Focal Sib-T and Klipsch R-51M compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
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Drivers
Both Sib-T and R-51M are 2-way speakers.
| Driver |
Focal Sib-T |
Klipsch R-51M |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
.75-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.125-inch
|
1 x 5.25-inch
|
Sib-T features a .75" Dome Tweeter and 1 x 5.125" 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-T has a frequency range of 80-20kHz 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-T's min frequency of 80Hz.
Below graphs depict how these two speakers compare with the max, min and average values of the Min and Max Frequencies of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
High Frequency
Bookshelf Speakers
None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
Sib-T is a 4 ohms speaker compared to the R-51M 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 Sib-T can provide this impedance level.
These two speakers also have different sensitivity levels. Sib-T 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-T, hence will play louder with the same amount of watts.
Sensitivity
Bookshelf Speakers
Input Type and Bi-Amping / Bi-Wiring
Sib-T 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-T's Spring posts terminals
Klipsch R-51M's Single Gold Plated Binding Posts - 5-way terminals
Physical Specs
Size of a speaker can sometimes become 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-T's and Klipsch R-51M's external dimensions. Focal Sib-T has external dimensions of 64.0 x 143.0 x 170.0mm ( 2-1/2 x 5-5/8 x 6-11/16inch) 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 35mm wider, 274mm taller and 45mm deeper than Focal Sib-T.
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-T is approximately 243.1cm2 / 37.7inch2 and base area of the Klipsch R-51M is approximately 382.7cm2 / 59.3inch2. The Sib-T requires 36% 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-T weighs 2.60kg / 5.7lbs and the Klipsch R-51M weighs 5.00kg / 11lbs. This makes the R-51M 92% heavier than the Sib-T.
Here is a comparison of how Sib-T 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-T?
Here are the items that are included inside the box of Sib-T:
One 100V/4-ohm commercial speakerAdjustable mounting bracket (installed)3 Drywall anchors w/ 2 screws5mm Allen key (attached to mounting bracket)User manual
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
 Mounting Bracket |
Yes
vs
No
|
Allows mounting on walls |
 Height |
64mm
vs
338mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
243cm2 (143x170mm)
vs
382cm2 (178x215mm)
|
Takes less floor space |
 Sensitivity |
93 dB
vs
90 dB
|
Play louder with same amount of amplification power |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
 Woofer Size |
5.25 inches
vs
5.125 inches
|
Larger woofer |
| Low Frequency Response |
62 Hz
vs
80 Hz
|
Generates deeper bass |
 High Frequency Response |
21k Hz
vs
20k Hz
|
Generates higher frequency |
 Price per pair* |
359USD
vs
698USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Focal Sib-T |
Klipsch Reference R-51M |
| Brand |
Focal |
Klipsch |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Sensitivity |
90 dB |
93 dB |
| Impedance |
4 ohms |
8 ohms |
| Frequency Response |
80-20kHz |
62-21k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.125" |
5.25" |
| Woofer Composition |
Polyflex |
Copper-spun IMG |
| Woofer Surround Material |
Not given |
Rubber |
| Tweeter Size |
.75" |
1" |
| Tweeter Type |
Dome |
Tractrix Horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
1660Hz |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
64.0mm (2.5") |
338.0mm (13.3") |
| Width |
143.0mm (5.6") |
178.0mm (7") |
| Depth |
170.0mm (6.7") |
215.0mm (8.5") |
| Weight |
2.60kg (5.7lbs) |
5.00kg (11lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
Plastic |
MDF/Wood-grain vinyl |
| Available Colors |
White |
Black |
| Mounting Bracket |
Yes |
No |
| Recommended Stand Height |
2-1/2" |
24-28" |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |