In this review, we will be comparing Ultra Bookshelf and R-51M, two Passive Bookshelf speakers from SVS and Klipsch.
Let's have a brief look at the main features
of SVS Ultra Bookshelf and Klipsch R-51M first before getting into our more
detailed comparison.
| Key Specs | SVS Ultra Bookshelf | Klipsch R-51M |
|---|
| Brand | SVS
United States · founded 1998 | Klipsch
United States · founded 1946 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" Hard-Dome | 1" Tractrix Horn |
|---|
| Woofer | 6.5" Composite glass-fiber | 5.25" Copper-spun IMG |
|---|
| Frequency response | 45-32k Hz | 62-21k Hz |
|---|
| Sensitivity | 87 dB | 93 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 20-150 watts | Up to 85 watts |
|---|
| Weight | 8.64kg / 19lbs | 5.00kg / 11lbs |
|---|
| Dimensions (H x W x D) | 14-15/16" x 8-9/16" x 11-1/16"
380.0 x 218.0 x 281.0mm | 13.3" x 7.0" x 8.4"
338.0 x 178.0 x 215.0mm |
|---|
What size room are the SVS Ultra Bookshelf 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* |
SVS Ultra Bookshelf |
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.
Drivers
Both Ultra Bookshelf and R-51M are 2-way speakers.
SVS Ultra BookshelfKlipsch 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 |
SVS Ultra Bookshelf |
Klipsch R-51M |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 6.5-inch
|
1 x 5.25-inch
|
Ultra Bookshelf features a 1" aluminum Hard-Dome Tweeter and 1 x 6.5" Composite glass-fiber Woofer with a Crossover frequency at 2000Hz. 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
Ultra Bookshelf has a frequency range of 45-32k Hz whereas R-51M has a frequency range of 62-21k Hz. With a minimum frequency of 45Hz, the Ultra Bookshelf can go significantly deeper on the low side and provide stronger bass compared to the R-51M's min frequency of 62Hz.
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
Ultra Bookshelf and R-51M have the same Impedance of 8 ohms but where they differ is the sensitivity levels. Ultra Bookshelf sensitivity is rated at 87 dB and the R-51M's is at 93 dB. This 6 dB difference makes the Klipsch R-51M a more sensitive speaker compared to SVS Ultra Bookshelf, 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.
Ultra Bookshelf can handle a max power of 150 watts RMS, whereas R-51M has a max power handling value of 85 watts RMS, 65 watts less than the Ultra Bookshelf.
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
Ultra Bookshelf features 5-way post posts which make bi-amping or bi-wiring possible. R-51M has a Single Gold Plated Binding Posts - 5-way which doesn't feature bi-amping/bi-wiring.
SVS Ultra Bookshelf's 5-way post terminals allows Bi-amping or bi-wiring
Klipsch R-51M's Single Gold Plated Binding Posts - 5-way terminals
Cabinet Type and Port Position
Both Ultra Bookshelf 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.
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 SVS Ultra Bookshelf's and Klipsch R-51M's external dimensions. SVS Ultra Bookshelf has external dimensions of 380.0 x 218.0 x 281.0mm (14-15/16 x 8-9/16 x 11-1/16inch) whereas Klipsch R-51M has external dimensions of 338.0 x 178.0 x 215.0mm (13.3 x 7.0 x 8.4inch).
SVS Ultra Bookshelf is clearly the larger of the two speakers. Its body is 40mm wider, 42mm taller and 66mm deeper than Klipsch R-51M.
Below you can see the front view size comparison of SVS Ultra Bookshelf and Klipsch R-51M in scale.
Comparison image of SVS Ultra Bookshelf 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 SVS Ultra Bookshelf is approximately 612.6cm2 / 95.0inch2 and base area of the Klipsch R-51M is approximately 382.7cm2 / 59.3inch2. The Ultra Bookshelf requires 60% more surface area than the R-51M 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 SVS Ultra Bookshelf and Klipsch R-51M 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 SVS Ultra Bookshelf weighs 8.64kg / 19lbs and the Klipsch R-51M weighs 5.00kg / 11lbs. This makes the Ultra Bookshelf 73% heavier than the R-51M.
Here is a comparison of how Ultra Bookshelf 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 SVS Ultra Bookshelf?
Here are the items that are included inside the box of Ultra Bookshelf:
- 2 Bookshelf loudspeakers
- 2 Grilles
- 8 Rubber feet
- 2 Terminal jumpers (pre-installed)
- Owners Manual
- SVS brochure
- Online Product Registration 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 |
150 watts
vs
85 watts
|
Handle more power from your amplifier |
 Woofer Size |
6.5 inches
vs
5.25 inches
|
Larger woofer |
|
Low Frequency Response |
45 Hz
vs
62 Hz
|
Generates deeper bass |
 High Frequency Response |
32k Hz
vs
21k Hz
|
Generates higher frequency |
 Bi-Amping and Bi-Wiring |
Yes
vs
No
|
Allows bi-amping and bi-wiring connections |
 Sensitivity |
93 dB
vs
87 dB
|
Play louder with same amount of amplification power |
 Height |
338mm
vs
380mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
382cm2
vs
612cm2
|
Takes less floor space |
 Price per pair* |
359USD
vs
1200USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
SVS Ultra Bookshelf |
Klipsch Reference R-51M |
| Brand |
SVS |
Klipsch |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
20-150 watts |
Up to 85 watts |
| Sensitivity |
87 dB |
93 dB |
| Impedance |
8 ohms |
8 ohms |
| Frequency Response |
45-32k Hz |
62-21k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6.5" |
5.25" |
| Woofer Composition |
Composite glass-fiber |
Copper-spun IMG |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Hard-Dome |
Tractrix Horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2000Hz |
1660Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
380.0mm (15") |
338.0mm (13.3") |
| Width |
218.0mm (8.6") |
178.0mm (7") |
| Depth |
281.0mm (11.1") |
215.0mm (8.5") |
| Weight |
8.64kg (19lbs) |
5.00kg (11lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Oak veneer |
MDF/Wood-grain vinyl |
| Available Colors |
Black Oak,Piano Gloss Black,Piano Gloss White |
Black |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
22-28" |
24-28" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
These sit in different price classes - SVS Ultra Bookshelf costs roughly 3.3x what Klipsch R-51M 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 | SVS Ultra Bookshelf digs deeper - 45Hz against 62Hz. |
| Amplifier needs | B | Klipsch R-51M is more sensitive (93dB vs 87dB), so it goes louder on the same amplifier. |
| Headroom | A | SVS Ultra Bookshelf takes more power (150W vs 85W) - more in hand in a big room. |
| Size | depends | Klipsch R-51M is easier to place; SVS Ultra Bookshelf is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | A | SVS Ultra Bookshelf: bi-amping. |
| Price | B | Klipsch R-51M is cheaper - $359 against $1,200, about 70% less; arguably a different class. |
A SVS Ultra Bookshelf 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?
The usual trade-off: SVS Ultra Bookshelf measures better, Klipsch R-51M costs about about 3.3x the price% less. Whether that gap is worth the money is the call only you can make - and in a normal room it is often smaller than the numbers suggest. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 62Hz anyway, which makes the cheaper Klipsch R-51M much easier to justify. Match it to your room: we rate SVS Ultra Bookshelf 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.