Klipsch Reference R-51M is a 2-way Passive Bass Reflex Bookshelf speaker by Klipsch. It features a 1" Tractrix Horn Tweeter and 1 x 5.25" Copper-spun IMG Woofer. The speaker has a frequency range of 62-21k Hz and a sensitivity of 93 dB. Klipsch R-51M has an MSRP of 359$ per pair but can often be found around 199$ per pair.
Room Size Suitability
The size of the room where you plan to use the Klipsch R-51M is a crucial factor in your decision. We have assessed its suitability for various room sizes based on its dimensions and maximum power output:
| Listening Environment* | Suitability |
|---|---|
| Near-field | Average |
| Small Room | Good |
| Mid-size Room | Average |
| Large Room | Poor |
| Very Large Room | 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.)
Klipsch's Reference (R) Bookshelf Series of Loudspeakers
R-51M is a member of Klipsch's Reference (R) Bookshelf series of Passive speakers. Below you can see the main specs of these speakers.
Klipsch Reference (R) Bookshelf Series Speakers
| Model | Frequency | Sensitivity | Impedance | Woofer | |
|---|---|---|---|---|---|
 | Klipsch R-51M | 62-21k Hz | 93 dB | 8Ω | 1 x 5.25" |
 | Klipsch R-41M Compare | 68-21k Hz | 90 dB | 8Ω | 1 x 4" |
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Frequency Response of the Klipsch R-51M Speaker
Klipsch R-51M has a Frequency response range of 62-21k Hz at ±3dB and Power Range of Up to 85 watts. With a minimum frequency of 62 Hz, it is hard to expect a strong bass response from R-51M so depending on your use case, using a subwoofer will significantly help to widen the response range.
To focus on the subwoofers that are in a similar price range with Klipsch R-51M, check out the Powered Subwoofers under $500. Alternatively, find the Full list of Powered Subwoofers regardless of the price.
Here we have a comparison of how R-51M's Low and High frequency values compare with the average, max and min Low and High frequency values in its class.
Low Frequency
Bookshelf Speakers
Klipsch R-51M
Min
Average
Max
High Frequency
Bookshelf Speakers
Klipsch R-51M
Min
Average
Max
Crossover frequency of the Klipsch R-51M?
The Crossover frequency of the R-51M is set to 1660Hz. This is the threshold frequency where the higher frequency signals over this level are sent to the tweeter and the lower-frequency signals are sent to the woofer by the crossover component.
Impedance and Sensitivity
Klipsch R-51M's nominal impedance level is 8 ohms and has a sensitivity of 93 dB.
Sensitivity
Bookshelf Speakers
Klipsch R-51M
Min
Max
8 Ohms is pretty much the standard nominal impedance amongst stereo speakers and amplifiers so Klipsch Reference R-51M is not considered a difficult to drive speaker from nominal Impedance perspective.
Sensitivity
93dB of the Klipsch Reference R-51M is considered a high sensitivity compared to average stereo speaker which makes R-51M an easy to drive from Sensitivity perspective. If you are planning to power your speaker with a Tube amp which are generally very low power, the Klipsch R-51M will be a good choice.
Check the amplifiers that are in a similar price range to the Klipsch R-51M:
- Integrated Amps under 300 USD
- Integrated Amps under 500 USD
- Integrated Amps under 750 USD
- All Integrated Amplifiers
Input Type
R-51M features Single Gold Plated Binding Posts - 5-way type connectors. Bi-amping and Bi-wiring are not possible.
Klipsch R-51M External Dimensions and Weight
Klipsch R-51M has external dimensions of (Height x Width x Depth) 13.3 x 7.0 x 8.4inch (338.0 x 178.0 x 215.0mm ).
Base Surface Area
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited. The base area of Klipsch R-51M is approximately 382.7cm2 / 59.3inch2.
To get a better perspective on the real life size of Klipsch R-51M, let's compare it with a standard size Compact Disc which has a diameter of 4.7inch (120mm).
Here we place the Klipsch R-51M virtually next to a standard width amplifier and turntable on a BDI Octave Media Cabinet to get a better idea about the size.
Weight
The Klipsch R-51M weighs 5.00kg / 11lbs per piece. Here is a comparison of how R-51M's weight compares with the average, max and min weights in its class.
Weight
All Bookshelf Speakers
Klipsch R-51M
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Average
Max
Weight
Bookshelf Speakers under $500
Klipsch R-51M
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Average
Max
Cabinet type and Materials
Klipsch R-51M has a Bass Reflex type cabinet and a MDF/Wood-grain vinyl finish. Bass Reflex type loudspeakers (aka Ported, Vented or Reflex Port) have enclosures that uses a port, hole or vent cut into the cabinet. Ported designs are generally more efficient than the Sealed designs.
Speaker Feet
Klipsch R-51M comes with 8 Self-adhesive rubber feet which you can use to secure your loudspeaker on the surface that you are putting on. It is always recommended to use some kind of feet under all types of speakers. Besides limiting the movement of the speakers, it also compensates for non-flat surfaces and limits the contact surface area of the speaker. Rubber based feet also help isolating the vibrations within certain frequency ranges.
Port Position
Klipsch R-51M is a rear-firing port speaker so you have to make sure you leave enough space between the back of the speaker and wall or bookshelf so that it has room to breathe.
Available colors
Klipsch R-51M is available in Black.
Wall Mounting
R-51M doesn't sport any built-in mounting bracket, so you need an external structure to mount it on walls.
Does the Klipsch R-51M come with a Grille?
R-51M comes with magnetic grilles in black color choices. The purpose of the grille is to protect the delicate driver elements from external impacts while still allowing the sound to pass as clearly as possible. Since the included grille of the R-51M is magnetic type, it is very easy to put it on and off.
What's in the Box of Klipsch R-51M?
Here are the items that are included inside the box of R-51M:
Recommended Accessories
Here is a list of accessories that we think you may need for the Klipsch Reference R-51M.
- Speaker Cable and Connectors
- Speaker Cables with Banana Plugs: If you know the lenght of the cable you need, this is the easier option to connect your speakers with your amp.
- Speaker Cables without Connectors: If you are not sure about the lenght or need longer than standard cables with plugs, choose this option.
- Banana Connectors and Plugs: If you chose the cables without connectors option or already have some cable around, pick the banana plugs separately.
- Vibration Isolators: IsoAcoustics isolators more affordable options too.
- Acoustic Panels and Treatments: Your room is as important as your stereo equipment so acoustic treatments goes a long way in improving the overall performance.
- Speaker Stands: Stands bring your bookshelf speakers to ideal height (rule of thumb is to have the tweeter level with your ear in your listening position), helps stability and acoustical isolation.
User's Manual
For more information about how to setup, use and maintain the Klipsch Reference R-51M, use the direct link below to download the official manual document:
Download User Manual for Klipsch R-51M
Official Brochure
Here is a link to download the official brochure for the Klipsch Reference R-51M speaker:
Official Brochure for Klipsch R-51M
Official Product Page
Official manufacturer's product page for the Klipsch Reference R-51M speaker can be found below:
Official Product Page for Klipsch R-51M
Warranty
5 Years of parts warranty and 5 Years of labor warranty is generally provided by the manufacturer.
