In this review, we will be comparing R-51PM and A5+ Wireless, two Powered Bookshelf speakers from Klipsch and Audioengine. 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-51PM and Audioengine A5+ Wireless first before getting into our more
detailed comparison.
| Key Specs | Klipsch R-51PM | Audioengine A5+ Wireless |
|---|
| Brand | Klipsch
United States · founded 1946 | Audioengine
United States · founded 2005 |
|---|
| Design | 2-way | 2-way |
|---|
| Built-in amplifier | 120-watt RMS (240-watt peak) | 100-watt RMS |
|---|
| Tweeter | 1.0" Tractrix Horn | 0.75" Soft-Dome |
|---|
| Woofer | 5.25" Copper-spun IMG | 5" Kevlar |
|---|
| Frequency response | 68-21k Hz | 50-22k Hz |
|---|
| Max depth / sample rate | 24-bit / 96 kHz | 24-bit / 44.1 kHz |
|---|
| Bluetooth | Built-in 3.0 | Built-in 4.0 |
|---|
| Weight | 4.80kg / 10.6lbs | 4.40kg / 9.7lbs |
|---|
| Dimensions (H x W x D) | 13" x 7.0625" x 10.25"
330.2 x 179.4 x 260.3mm | 10.875" x 7.1875" x 9.75"
276.2 x 182.6 x 247.6mm |
|---|
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both R-51PM and A5+ Wireless are 2-way speakers.
Klipsch R-51PMAudioengine A5+ Wireless
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-51PM |
Audioengine A5+ Wireless |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1.0-inch
|
0.75-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 5-inch
|
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. On the other hand, the A5+ Wireless features a 0.75" Silk Soft-Dome Tweeter and 1 x 5" Kevlar Woofer.
Frequency Response
R-51PM has a frequency range of 68-21k Hz whereas A5+ Wireless has a frequency range of 50-22k Hz. With a minimum frequency of 50Hz, the A5+ Wireless 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-51PM and A5+ Wireless 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-51PM's and Audioengine A5+ Wireless's external dimensions. Klipsch R-51PM has external dimensions of 330.2 x 179.4 x 260.3mm (13 x 7.0625 x 10.25inch) whereas Audioengine A5+ Wireless has external dimensions of 276.2 x 182.6 x 247.6mm (10.875 x 7.1875 x 9.75inch).
Audioengine A5+ Wireless is 54mm shorter and 12.7mm less deeper than Klipsch R-51PM but it is also 3.2mm wider.
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-51PM is approximately 467.0cm2 / 72.4inch2 and base area of the Audioengine A5+ Wireless is approximately 452.1cm2 / 70.1inch2. The R-51PM requires 3% more surface area than the A5+ Wireless which gives it a small disadvantage 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-51PM weighs 4.80kg / 10.6lbs and the Audioengine A5+ Wireless weighs 4.40kg / 9.7lbs. This makes the R-51PM 9% heavier than the A5+ Wireless.
Here is a comparison of how R-51PM and A5+ Wireless'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-51PM?
Here are the items that are included inside the box of R-51PM:
- Powered speaker (right)
- Passive speaker (left)
- 2 Grilles
- 68-inch AC power cord
- Remote control
- 2
What's in the Box of Audioengine A5+ Wireless?
Here are the items that come with the A5+ Wireless:
- Powered left speaker
- Passive right speaker
- 6-feet AC power cord
- Remote control (with installed CR2025 battery)
- Antenna
- 12.5-feet Length of 16 gauge speaker wire
- 6.5-feet Stereo minijack cable
- 6-feet Stereo RCA cable
- Cloth drawstring cable bag
- 2 Cloth drawstring speaker bags
- Setup guide
- Audioengine product brochure
 Woofer Size |
5.25 inches
vs
5 inches
|
Larger woofer |
 USB Port |
USB-B
vs
No
|
USB port adds flexibility |
 Phono Input |
Yes
vs
No
|
Connect your turntable directly |
 Digital Input |
Optical
vs
No
|
Connect digital inputs directly |
|
Low Frequency Response |
50 Hz
vs
68 Hz
|
Generates deeper bass |
 High Frequency Response |
22k Hz
vs
21k Hz
|
Generates higher frequency |
 Height |
276mm
vs
330mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
452cm2
vs
467cm2
|
Takes less floor space |
 Price per pair* |
499USD
vs
599USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Klipsch Reference R-51PM |
Audioengine A5+ Wireless |
| Brand |
Klipsch |
Audioengine |
| Speaker Type |
Powered Stereo Speakers |
Powered Stereo Speakers |
| Frequency Response |
68-21k Hz |
50-22k Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
120-watt RMS |
100-watt RMS |
| Watts Peak (Max) |
240-watt RMS |
n/a |
| Max Bit Depth |
24-bit |
24-bit |
| Max Sample Rate |
96 kHz |
44.1 kHz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
5" |
| Woofer Composition |
Copper-spun IMG |
Kevlar |
| Tweeter Size |
1.0" |
0.75" |
| Tweeter Type |
Tractrix Horn |
Soft-Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
1663Hz |
n/a |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
330.2mm (13") |
276.2mm (10.9") |
| Width |
179.4mm (7.1") |
182.6mm (7.2") |
| Depth |
260.3mm (10.2") |
247.6mm (9.7") |
| Weight |
4.80kg (10.6lbs) |
4.40kg (9.7lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Available Colors |
n/a |
Black, Bamboo, White |
| Mounting Bracket |
No |
No |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Aux Inputs |
3.5mm, RCA |
3.5mm, RCA |
| USB Port |
USB-B |
No |
| Phone Input |
Yes |
No |
| Subwoofer Output |
Wired |
Wired |
| Digital Input |
Optical |
No |
| HDMI Input |
No |
No |
| Headphone Jack |
No |
No |
| Ethernet Port |
No |
No |
Other |
|
|
| Parts Warranty |
1 Year |
3 Years |
| Labor Warranty |
1 Year |
3 Years |
No single best speaker here - they are built to different priorities, and the right one depends on your room, your sources and what you listen to.
| Area | Better | Why |
|---|
| Bass | B | Audioengine A5+ Wireless digs deeper - 50Hz against 68Hz. |
| Built-in power | evenly matched | Similar onboard amplification (120W vs 100W RMS). |
| Connections | A | Klipsch R-51PM adds phono and digital inputs. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Expandability | depends | Klipsch R-51PM: a sub output; Audioengine A5+ Wireless: a sub output. |
| Price | B | Audioengine A5+ Wireless is cheaper - $499 against $599, about 17% less. |
A Klipsch R-51PM B Audioengine A5+ Wireless
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 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.