In this review, we will be comparing Ai61 and R-51PM, two Powered Bookshelf speakers from Fluance and 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 Fluance Ai61 and Klipsch R-51PM first before getting into our more
detailed comparison.
| Key Specs | Fluance Ai61 | Klipsch R-51PM |
|---|
| Brand | Fluance
Canada · founded 1999 | Klipsch
United States · founded 1946 |
|---|
| Design | 2-way | 2-way |
|---|
| Built-in amplifier | 120-watt RMS | 120-watt RMS (240-watt peak) |
|---|
| Tweeter | 1" Soft Dome | 1.0" Tractrix Horn |
|---|
| Woofer | 6.5" Woven, Glass Fiber Composite | 5.25" Copper-spun IMG |
|---|
| Frequency response | 32-20k Hz | 68-21k Hz |
|---|
| Power range | up to 120 watts | — |
|---|
| Max depth / sample rate | 16-bit / 48 kHz | 24-bit / 96 kHz |
|---|
| Bluetooth | Built-in 5.0 | Built-in 3.0 |
|---|
| Weight | 5.96kg / 13.1lbs | 4.80kg / 10.6lbs |
|---|
| Dimensions (H x W x D) | 13.1" x 7.8" x 9.2"
33.3 x 19.8 x 23.4 cm | 13" x 7.0625" x 10.25"
330.2 x 179.4 x 260.3mm |
|---|
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
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Drivers
Both Ai61 and R-51PM are 2-way speakers.
Fluance Ai61Klipsch 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 |
Fluance Ai61 |
Klipsch R-51PM |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1.0-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 6.5-inch
|
1 x 5.25-inch
|
Ai61 features a 1" Silk Neodymium Ferrofluid Cooled Soft Dome Tweeter and 1 x 6.5" Woven, Glass Fiber Composite Woofer. 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
Ai61 has a frequency range of 32-20k Hz whereas R-51PM has a frequency range of 68-21k Hz. With a minimum frequency of 32Hz, the Ai61 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 Ai61 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 Fluance Ai61's and Klipsch R-51PM's external dimensions. Fluance Ai61 has external dimensions of 33.3 x 19.8 x 23.4 cm (13.1 x 7.8 x 9.2 inches) 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 18.6mm narrower and 2.8mm shorter than Fluance Ai61 but it is also 26.3mm deeper.
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 Fluance Ai61 is approximately 463.0cm2 / 71.8inch2 and base area of the Klipsch R-51PM is approximately 467.0cm2 / 72.4inch2. The Ai61 requires 1% 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 Fluance Ai61 weighs 5.96kg / 13.1lbs and the Klipsch R-51PM weighs 4.80kg / 10.6lbs. This makes the Ai61 24% heavier than the R-51PM.
Here is a comparison of how Ai61 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 Fluance Ai61?
Here are the items that are included inside the box of Ai61:
- Ai61 Powered Bookshelf Speakers (pair)
- Remote Control
- 1x CR2032 Battery
- 6ft Power Cable
- 8ft 18 Gauge Speaker Wire
- Quick Start Guide
- Fluance Catalog
- Lifetime Customer Support
- 2 Year Manufacturer’s Warranty
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
 Woofer Size |
6.5 inches
vs
5.25 inches
|
Larger woofer |
|
Low Frequency Response |
32 Hz
vs
68 Hz
|
Generates deeper bass |
 Base Surface Area |
463cm2
vs
467cm2
|
Takes less floor space |
 Price per pair* |
299USD
vs
599USD
|
costs less (*prices may change depending on the seller, location and time) |
 USB Port |
USB-C
vs
No
|
USB port adds flexibility |
 High Frequency Response |
21k Hz
vs
20k Hz
|
Generates higher frequency |
 Height |
330mm
vs
333mm
|
Easier to fit in smaller spaces |
|
USB Port |
USB-B
vs
No
|
USB port adds flexibility |
 3.5mm Connection |
Yes
vs
No
|
Connection via 3.5mm AUX input |
 RCA Connection |
Yes
vs
No
|
Connection via RCA input |
 Phono Input |
Yes
vs
No
|
Connect your turntable directly |
| General |
Fluance Ai61 |
Klipsch Reference R-51PM |
| Brand |
Fluance |
Klipsch |
| Speaker Type |
Powered Stereo Speakers |
Powered Stereo Speakers |
| Frequency Response |
32-20k Hz |
68-21k Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
120-watt RMS |
120-watt RMS |
| Watts Peak (Max) |
n/a |
240-watt RMS |
| Max Bit Depth |
16-bit |
24-bit |
| Max Sample Rate |
48 kHz |
96 kHz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6.5" |
5.25" |
| Woofer Composition |
Woven, Glass Fiber Composite |
Copper-spun IMG |
| Woofer Surround Material |
Butyl Rubber |
n/a |
| Tweeter Size |
1" |
1.0" |
| Tweeter Type |
Soft Dome |
Tractrix Horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
1663Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
333.0mm (13.1") |
330.2mm (13") |
| Width |
198.0mm (7.8") |
179.4mm (7.1") |
| Depth |
234.0mm (9.2") |
260.3mm (10.2") |
| Weight |
5.96kg (13.1lbs) |
4.80kg (10.6lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF wood |
n/a |
| Available Colors |
Black Ash,Lucky Bamboo,White Walnut, Natural Walnut |
n/a |
| Mounting Bracket |
No |
No |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Aux Inputs |
RCA |
3.5mm, RCA |
| USB Port |
USB-C |
USB-B |
| Phone Input |
No |
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 |
| Labor Warranty |
|
1 Year |
These sit in different price classes - Klipsch R-51PM costs roughly 2x what Fluance Ai61 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 | Fluance Ai61 digs deeper - 32Hz against 68Hz. |
| Built-in power | evenly matched | Similar onboard amplification (120W vs 120W RMS). |
| Connections | B | Klipsch R-51PM adds phono. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Expandability | depends | Fluance Ai61: a sub output; Klipsch R-51PM: a sub output. |
| Price | A | Fluance Ai61 is cheaper - $299 against $599, about 50% less; arguably a different class. |
A Fluance Ai61 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?
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. Think about the whole system, not just the speakers: the roughly $300 saved by taking the cheaper pair would buy a subwoofer or a better amplifier, and either usually does more for the sound than the difference between these two.
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.