In this review, we will be comparing Nero MB5 and R-51M, two Passive Bookshelf speakers from OSD and Klipsch. Let's have a brief look at the main features
of OSD Nero MB5 and Klipsch R-51M first before getting into our more
detailed comparison.
What size room are the OSD Nero MB5 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:
In the following sections, we will get into more detail in order to better understand how the OSD Nero MB5 and Klipsch R-51M compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
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Drivers
Both Nero MB5 and R-51M are 2-way speakers.
| Driver |
OSD Nero MB5 |
Klipsch R-51M |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 5.25-inch
|
Nero MB5 features a 1" Soft-Dome Tweeter and 1 x 5.25" Fiberglass Woofer . 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
Nero MB5 has a frequency range of 50-30k Hz whereas R-51M has a frequency range of 62-21k Hz. With a minimum frequency of 50Hz, the Nero MB5 can go significantly deeper on the low side and provide stronger bass compared to the R-51M's min frequency of 62Hz.
Below graphs depict how these two speakers compare with the max, min and average values of the Min and Max Frequencies of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
High Frequency
Bookshelf Speakers
None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
Nero MB5 is a 4 ohms speaker compared to the R-51M which has a nominal impedance of 8 ohms. Lower impedance speakers, especially the ones that are rated at 4 ohms may put more pressure on the amplifier unit especially when played at high volume levels, so make sure the amp you pair with the Nero MB5 can provide this impedance level.
These two speakers also have different sensitivity levels. Nero MB5 sensitivity is rated at 90 dB and the R-51M's is rated at 93 dB. This 3 dB difference makes the Klipsch R-51M a more sensitive speaker compared to OSD Nero MB5, 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. While using an amplifier within this range ensures the nominal performance , inputting a power that is higher than the max wattage can result in a damaged speaker.
Nero MB5 can handle a max power of 100 watts RMS from the amp the whereas R-51M has a max power handling value of 85 watts RMS, 15 watts less than the Nero MB5.
Keep in mind that a higher max power handling value doesn't necessarily make that a louder speaker
compared to a lower max handling speaker. Loudness or the sound level is also impacted by parameters
such as Impedance, sensitivity and system efficiencies.
Input Type and Bi-Amping / Bi-Wiring
Nero MB5 features Single Gold Plated Binding Posts - 5-way type posts and R-51M has a Single Gold Plated Binding Posts - 5-way type posts. None of these speakers feature bi-amping/bi-wiring.
Klipsch R-51M's Single Gold Plated Binding Posts - 5-way terminals
Physical Specs
Size of a speaker can sometimes become an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare OSD Nero MB5's and Klipsch R-51M's external dimensions. OSD Nero MB5 has external dimensions of 304.0 x 177.8 x 245.0mm ( 11-15/16inch x 7-5/16inch x 9-5/8inch ) whereas Klipsch R-51M has external dimensions of 338.0 x 178.0 x 215.0mm ( 13.3 x 7.0 x 8.4inch) .
OSD Nero MB5 is 0.19999999999999mm narrower and 34mm shorter than Klipsch R-51M but it is also 30mm 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 OSD Nero MB5 is approximately 435.6cm2 / 67.5inch2 and base area of the Klipsch R-51M is approximately 382.7cm2 / 59.3inch2. The Nero MB5 requires 14% more surface area than the R-51M 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 OSD Nero MB5 weighs 5.45kg / 12lbs and the Klipsch R-51M weighs 5.00kg / 11lbs. This makes the Nero MB5 9% heavier than the R-51M.
Here is a comparison of how Nero MB5 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 OSD Nero MB5?
Here are the items that are included inside the box of Nero MB5:
2 Bookshelf loudspeakers2 Grilles
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 |
100 watts
vs
85 watts
|
Handle more power from your amplifier |
 Low Frequency Response |
50 Hz
vs
62 Hz
|
Generates deeper bass |
 High Frequency Response |
30k Hz
vs
21k Hz
|
Generates higher frequency |
 Height |
304mm
vs
338mm
|
Easier to fit in smaller spaces |
 Sensitivity |
93 dB
vs
90 dB
|
Play louder with same amount of amplification power |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
 Base Surface Area |
382cm2 (178x215mm)
vs
435cm2 (177x245mm)
|
Takes less floor space |
| General |
OSD Nero MB5 |
Klipsch Reference R-51M |
| Brand |
OSD |
Klipsch |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
100 watts |
Up to 85 watts |
| Sensitivity |
90 dB |
93 dB |
| Impedance |
4 ohms |
8 ohms |
| Frequency Response |
50-30k Hz |
62-21k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
5.25" |
| Woofer Composition |
Fiberglass |
Copper-spun IMG |
| Woofer Surround Material |
--- |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Soft-Dome |
Tractrix Horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
1660Hz |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
304.0mm (12") |
338.0mm (13.3") |
| Width |
177.8mm (7") |
178.0mm (7") |
| Depth |
245.0mm (9.6") |
215.0mm (8.5") |
| Weight |
5.45kg (12lbs) |
5.00kg (11lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
--- |
MDF/Wood-grain vinyl |
| Available Colors |
Black |
Black |
| Mounting Bracket |
|
No |
| Recommended Stand Height |
---" |
24-28" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
--- |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |