In this review, we will be comparing R-15PM and R-51PM, two Powered Bookshelf speakers by Klipsch. Being Powered speakers, they both have built-in amplifiers so you don't need an external power amp or an integrated amp to power them.
Let's have a brief look at the main features
of Klipsch R-15PM and Klipsch R-51PM first before getting into our more
detailed comparison.
| Key Specs | Klipsch R-15PM | Klipsch R-51PM |
|---|
| Brand | Klipsch
United States · founded 1946 | Klipsch
United States · founded 1946 |
|---|
| Design | 2-way | 2-way |
|---|
| Built-in amplifier | 100-watt RMS | 120-watt RMS (240-watt peak) |
|---|
| Tweeter | 1.0" Hard-Dome | 1.0" Tractrix Horn |
|---|
| Woofer | 5.25" Copper-spun IMG | 5.25" Copper-spun IMG |
|---|
| Frequency response | 62-24k Hz | 68-21k Hz |
|---|
| Max depth / sample rate | 24-bit / 96 kHz | 24-bit / 96 kHz |
|---|
| Bluetooth | Built-in 3.0 | Built-in 3.0 |
|---|
| Weight | 4.67kg / 10.3lbs | 4.80kg / 10.6lbs |
|---|
| Dimensions (H x W x D) | 12.5" x 7" x 9.875"
317.5 x 177.8 x 250.8mm | 13" x 7.0625" x 10.25"
330.2 x 179.4 x 260.3mm |
|---|
R-15PM and R-51PM are members of Klipsch's Reference (R) Bookshelf series of speakers. Below you can find the loudspeakers from this series.
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both R-15PM and R-51PM are 2-way speakers.
Klipsch R-15PMKlipsch R-51PM
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Klipsch R-15PM |
Klipsch R-51PM |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1.0-inch
|
1.0-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 5.25-inch
|
R-15PM features a 1.0" Aluminum Hard-Dome Tweeter and 1 x 5.25" Copper-spun IMG Woofer with a Crossover frequency at 1800Hz. On the other hand, the R-51PM features a 1.0" Aluminum LTS Tractrix Horn Tweeter and 1 x 5.25" Copper-spun IMG Woofer with a Crossover frequency at 1663Hz.
Frequency Response
R-15PM has a frequency range of 62-24k Hz whereas R-51PM has a frequency range of 68-21k Hz. With a minimum frequency of 62Hz, the R-15PM can go significantly deeper on the low side and provide stronger bass compared to the R-51PM's min frequency of 68Hz.
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.
Cabinet Type and Port Position
Both R-15PM and R-51PM 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 Klipsch R-15PM's and Klipsch R-51PM's external dimensions. Klipsch R-15PM has external dimensions of 317.5 x 177.8 x 250.8mm (12.5 x 7 x 9.875inch) whereas Klipsch R-51PM has external dimensions of 330.2 x 179.4 x 260.3mm (13 x 7.0625 x 10.25inch).
Klipsch R-51PM is clearly the larger of the two speakers. Its body is 1.6mm wider, 12.7mm taller and 9.5mm deeper than Klipsch R-15PM.
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 Klipsch R-15PM is approximately 445.9cm2 / 69.1inch2 and base area of the Klipsch R-51PM is approximately 467.0cm2 / 72.4inch2. The R-15PM requires 5% less surface area than the R-51PM 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 Klipsch R-15PM weighs 4.67kg / 10.3lbs and the Klipsch R-51PM weighs 4.80kg / 10.6lbs. This makes the R-51PM 3% heavier than the R-15PM.
Here is a comparison of how R-15PM and R-51PM's weights compare with the average, max and min weights in Powered Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Klipsch R-15PM?
Here are the items that are included inside the box of R-15PM:
- Powered speaker (right)
- Passive speaker (left)
- 68-inch AC power cord
- Remote control
- CR2025 3V battery (installed in remote)
- 16-feet Length of 18AWG speaker wire (bare tinned wire on each end)
- 6.5-feet USB-A to USB-B cable
- 6-feet Stereo RCA cable
- 5-feet Optical digital cable
- 8 Self-adhesive rubber feet
- Instruction Booklet
- Warranty Information
- Important Safety Instructions
What's in the Box of Klipsch R-51PM?
Here are the items that come with the R-51PM:
- Powered speaker (right)
- Passive speaker (left)
- 2 Grilles
- 68-inch AC power cord
- Remote control
- 2
 Low Frequency Response |
62 Hz
vs
68 Hz
|
Generates deeper bass |
 High Frequency Response |
24k Hz
vs
21k Hz
|
Generates higher frequency |
 Height |
317mm
vs
330mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
445cm2
vs
467cm2
|
Takes less floor space |
 Price per pair* |
499USD
vs
599USD
|
costs less (*prices may change depending on the seller, location and time) |
 USB Port |
Type-B
vs
No
|
USB port adds flexibility |
|
USB Port |
USB-B
vs
No
|
USB port adds flexibility |
| General |
Klipsch Reference R-15PM |
Klipsch Reference R-51PM |
| Brand |
Klipsch |
Klipsch |
| Speaker Type |
Powered Stereo Speakers |
Powered Stereo Speakers |
| Frequency Response |
62-24k Hz |
68-21k Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
100-watt RMS |
120-watt RMS |
| Watts Peak (Max) |
n/a |
240-watt RMS |
| Max Bit Depth |
24-bit |
24-bit |
| Max Sample Rate |
96 kHz |
96 kHz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
5.25" |
| Woofer Composition |
Copper-spun IMG |
Copper-spun IMG |
| Tweeter Size |
1.0" |
1.0" |
| Tweeter Type |
Hard-Dome |
Tractrix Horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
1800Hz |
1663Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
317.5mm (12.5") |
330.2mm (13") |
| Width |
177.8mm (7") |
179.4mm (7.1") |
| Depth |
250.8mm (9.9") |
260.3mm (10.2") |
| Weight |
4.67kg (10.3lbs) |
4.80kg (10.6lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Mounting Bracket |
No |
No |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Aux Inputs |
3.5mm, RCA |
3.5mm, RCA |
| USB Port |
Type-B |
USB-B |
| Phone Input |
Yes |
Yes |
| Subwoofer Output |
Wired |
Wired |
| Digital Input |
Optical |
Optical |
| HDMI Input |
No |
No |
| Headphone Jack |
No |
No |
| Ethernet Port |
No |
No |
Other |
|
|
| Parts Warranty |
1 Year |
1 Year |
| Labor Warranty |
1 Year |
1 Year |
Siblings in Klipsch's Reference (R) Bookshelf series, so they share a family sound. It comes down to size, output and price.
| Area | Better | Why |
|---|
| Bass | A | Klipsch R-15PM digs deeper - 62Hz against 68Hz. A subwoofer would even that out. |
| Built-in power | evenly matched | Similar onboard amplification (100W vs 120W RMS). |
| Connections | evenly matched | The same set of inputs and streaming options. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Expandability | depends | Klipsch R-15PM: a sub output; Klipsch R-51PM: a sub output. |
| Price | A | Klipsch R-15PM is cheaper - $499 against $599, about 17% less. |
A Klipsch R-15PM B Klipsch R-51PM
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-15PM has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 68Hz anyway, so judge these on the other rows instead.
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.