In this review, we will be comparing Model Three and R-51M, two Passive Bookshelf speakers from KLH and Klipsch. Let's have a brief look at the main features
of KLH Model Three and Klipsch R-51M first before getting into our more
detailed comparison.
What size room are the KLH Model Three 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 KLH Model Three 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 Model Three and R-51M are 2-way speakers.
| Driver |
KLH Model Three |
Klipsch R-51M |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 8-inch
|
1 x 5.25-inch
|
Model Three features a 1" Aluminum Tweeter and 1 x 8" Pulp-Paper Cone Woofer with a Crossover frequency at 1600Hz. 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
Model Three has a frequency range of 46-20k Hz whereas R-51M has a frequency range of 62-21k Hz. With a minimum frequency of 46Hz, the Model Three 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
Model Three is a 6 ohms speaker compared to the R-51M which has a nominal impedance of 8 ohms.
These two speakers also have different sensitivity levels. Model Three sensitivity is rated at 88 dB and the R-51M's is rated at 93 dB. This 5 dB difference makes the Klipsch R-51M a more sensitive speaker compared to KLH Model Three, 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.
Model Three can handle a max power of 150 watts RMS from the amp the whereas R-51M has a max power handling value of 85 watts RMS, 65 watts less than the Model Three.
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
Model Three 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.
KLH Model Three's Binding post terminals
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 KLH Model Three's and Klipsch R-51M's external dimensions. KLH Model Three has external dimensions of 482.0 x 311.0 x 267.0mm ( 19.0 x 12.25 x 10.5inch) whereas Klipsch R-51M has external dimensions of 338.0 x 178.0 x 215.0mm ( 13.3 x 7.0 x 8.4inch) .
KLH Model Three is clearly the larger of the two speakers. Its body is 133mm wider, 144mm taller and 52mm deeper than Klipsch R-51M.
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 KLH Model Three is approximately 830.4cm2 / 128.7inch2 and base area of the Klipsch R-51M is approximately 382.7cm2 / 59.3inch2. The Model Three requires 117% 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 KLH Model Three weighs 13.20kg / 29lbs and the Klipsch R-51M weighs 5.00kg / 11lbs. This makes the Model Three 164% heavier than the R-51M.
Here is a comparison of how Model Three 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 KLH Model Three?
Here are the items that are included inside the box of Model Three:
Floorstanding loudspeakerRiser baseGrilleOwners Manual
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 |
150 watts
vs
85 watts
|
Handle more power from your amplifier |
 Woofer Size |
8 inches
vs
5.25 inches
|
Larger woofer |
| Low Frequency Response |
46 Hz
vs
62 Hz
|
Generates deeper bass |
 Sensitivity |
93 dB
vs
88 dB
|
Play louder with same amount of amplification power |
 Nominal Impedance |
8 ohms
vs
6 ohms
|
Less selective with amplifiers |
 High Frequency Response |
21k Hz
vs
20k Hz
|
Generates higher frequency |
 Height |
338mm
vs
482mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
382cm2 (178x215mm)
vs
830cm2 (311x267mm)
|
Takes less floor space |
| General |
KLH Model Three |
Klipsch Reference R-51M |
| Brand |
KLH |
Klipsch |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
30-150 watts |
Up to 85 watts |
| Sensitivity |
88 dB |
93 dB |
| Impedance |
6 ohms |
8 ohms |
| Impedance |
3.7 ohms |
n/a |
| Frequency Response |
46-20k Hz |
62-21k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
5.25" |
| Woofer Composition |
Pulp-Paper Cone |
Copper-spun IMG |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
n/a |
Tractrix Horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
1600Hz |
1660Hz |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
482.0mm (19") |
338.0mm (13.3") |
| Width |
311.0mm (12.2") |
178.0mm (7") |
| Depth |
267.0mm (10.5") |
215.0mm (8.5") |
| Weight |
13.20kg (29lbs) |
5.00kg (11lbs) |
| Enclosure |
Acoustic Suspension |
Bass Reflex |
| Finish |
MDF/Wood Veneer |
MDF/Wood-grain vinyl |
| Available Colors |
English Walnut, West African Mahogany |
Black |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
n/a |
24-28" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
10 Years |
5 Years |
| Labor Warranty |
10 Years |
5 Years |