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JBL L100 Classic MKII vs Klipsch R-51M Comparison

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JBL L100 Classic MKII

Passive Bookshelf | 40-40k Hz

JBL L100 Classic MKII
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Klipsch R-51M

Passive Bookshelf | 62-21k Hz

Klipsch Reference R-51M
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JBL L100 Classic MKII JBL L100 Classic MKI...
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Klipsch R-51M Klipsch R-51M
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JBL L100 Classic MKI...
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Klipsch R-51M
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JBL L100 Classic MKII vs Klipsch R-51M Speaker Comparison

In this review, we will be comparing L100 Classic MKII and R-51M, two Passive Bookshelf speakers from JBL and Klipsch.

Let's have a brief look at the main features of JBL L100 Classic MKII and Klipsch R-51M first before getting into our more detailed comparison.

JBL L100 Classic MKII Key Specs

  • 3-way Design
  • 1" Dome Tweeter
  • 5.25" Midrange
  • 12" Pulp Woofer
  • 40-40k Hz Frequency Response
  • 90 dB Sensitivity
  • Impedance: 4ohms
  • Power Range:25-200watts
  • Weight:28.60kg
  • Dimensions (H x W x D): 636.5" x 15.3" x 14.6"( 636.5 x 389.6 x 371.5mm )

Klipsch R-51M Key Specs

  • 2-way Design
  • 1" Tractrix Horn Tweeter
  • 5.25" Copper-spun IMG Woofer
  • 62-21k Hz Frequency Response
  • 93 dB Sensitivity
  • Impedance: 8ohms
  • Power Range:Up to 85watts
  • Weight:5.00kg
  • Dimensions (H x W x D): 338.0" x 7.0" x 8.4"( 338.0 x 178.0 x 215.0mm )

What size room are the JBL L100 Classic MKII 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:

Listening Environment* JBL L100 Classic MKII Klipsch R-51M
Near-field Poor Average
Small Room Average Good
Mid-size Room Good Average
Large Room Average Poor
Very Large Room Poor 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.)

In the following sections, we will get into more detail in order to better understand how the JBL L100 Classic MKII 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.


**This post contains affiliate links, and I will be compensated if you make a purchase after clicking through my links. As an Amazon Associate I earn from qualifying purchases.


Drivers

One of the fundamental differences between these two speakers is that L100 Classic MKII is a 3-way design whereas the R-51M is a 2-way speaker. 3-way designs utilize a midrange driver in addition to the tweeter and woofer on 2-way designs. Designing a crossover for a 3-way speaker is a complicated process and generally increases the overall cost of the speaker.

Driver JBL L100 Classic MKII Klipsch R-51M
Driver Setup 3-way 2-way
Tweeter 1-inch 1-inch
Midrange 1 x 5.25-inch -
Woofer 1 x 12-inch 1 x 5.25-inch

L100 Classic MKII features a 1" Titanium Dome Tweeter , a 5.25" Midrange and 1 x 12" Pulp Woofer with a Crossover frequency at 450Hz and 3500Hz. 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

L100 Classic MKII has a frequency range of 40-40k Hz whereas R-51M has a frequency range of 62-21k Hz. With a minimum frequency of 40Hz, the L100 Classic MKII 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

L100 Classic MKII
R-51M
Min
Average
Max
High Frequency

Bookshelf Speakers

JBL L100 Classic MKII
Klipsch R-51M
Min
Average
Max

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

L100 Classic MKII 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 L100 Classic MKII can provide this impedance level.

These two speakers also have different sensitivity levels. L100 Classic MKII 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 JBL L100 Classic MKII, hence will play louder with the same amount of watts.

Sensitivity

Bookshelf Speakers

L100 Classic MKII
R-51M
Min
Average
Max

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.

L100 Classic MKII can handle a max power of 200 watts RMS from the amp the whereas R-51M has a max power handling value of 85 watts RMS, 115 watts less than the L100 Classic MKII.

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

L100 Classic MKII features Five-way gold-plated binding posts posts which make bi-amping or bi-wiring possible. R-51M has a Single Gold Plated Binding Posts - 5-way which doesn't feature bi-amping/bi-wiring.

JBL L100 Classic MKII Terminals
JBL L100 Classic MKII's Five-way gold-plated binding posts terminals allows Bi-amping or bi-wiring

Klipsch R-51MSingle Gold Plated Binding Posts - 5-way Terminals
Klipsch R-51M's Single Gold Plated Binding Posts - 5-way terminals

Cabinet Type and Port Position

L100 Classic MKII has a front firing port whereas R-51M has a rear firing ports. JBL L100 Classic MKII's front-firing port gives more flexibility in placement in regards to proximity to walls compared to Klipsch R-51M with its rear-firing port.

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 JBL L100 Classic MKII's and Klipsch R-51M's external dimensions. JBL L100 Classic MKII has external dimensions of 636.5 x 389.6 x 371.5mm ( 25.0 x 15.3 x 14.6inch) whereas Klipsch R-51M has external dimensions of 338.0 x 178.0 x 215.0mm ( 13.3 x 7.0 x 8.4inch) .

JBL L100 Classic MKII is clearly the larger of the two speakers. Its body is 211.6mm wider, 298.5mm taller and 156.5mm deeper than Klipsch R-51M.

Below you can see the front view size comparison of JBL L100 Classic MKII and Klipsch R-51M in scale.

JBL L100 Classic MKII vs Klipsch R-51M Size Comparison - Front View
Comparison image of JBL L100 Classic MKII and Klipsch R-51M Size and External Dimensions

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 JBL L100 Classic MKII is approximately 1447.4cm2 / 224.3inch2 and base area of the Klipsch R-51M is approximately 382.7cm2 / 59.3inch2. The L100 Classic MKII requires 278% 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 JBL L100 Classic MKII weighs 28.60kg / 62.9lbs and the Klipsch R-51M weighs 5.00kg / 11lbs. This makes the L100 Classic MKII 472% heavier than the R-51M.

Here is a comparison of how L100 Classic MKII and R-51M's weights compare with the average, max and min weights in Passive Bookshelf class.

Weight
All Bookshelf Speakers
JBL L100 Classic MKII
Klipsch R-51M
Min
Average
Max

What's in the Box of JBL L100 Classic MKII?

Here are the items that are included inside the box of L100 Classic MKII:
  • Bookshelf loudspeaker
  • Grille
  • Owner's 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

  • Reasons to choose JBL L100 Classic MKII over Klipsch Reference R-51M
    Max Input Power 200 watts vs 85 watts Handle more power from your amplifier
    Driver Setup 3-way vs 2-way Have a dedicated mid-range driver
    Woofer Size 12 inches vs 5.25 inches Larger woofer
    Low Frequency Response 40 Hz vs 62 Hz Generates deeper bass
    High Frequency Response 40k Hz vs 21k Hz Generates higher frequency
    Bi-Amping and Bi-Wiring Yes vs No Allows bi-amping and bi-wiring connections
    Port Position Front vs Rear Gives more flexibility placing close to walls

    Reasons to choose Klipsch Reference R-51M over JBL L100 Classic MKII

    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
    Height 338mm vs 636mm Easier to fit in smaller spaces
    Base Surface Area 382cm2 vs 1447cm2 Takes less floor space
    Price per pair* 359USD vs 4800USD costs less (*prices may change depending on the seller, location and time)
    JBL L100 Classic MKII vs Klipsch R-51M Specs Table
    Detailed comparison of specifications
    General JBL L100 Classic MKII Klipsch Reference R-51M
    Brand JBL Klipsch
    Speaker Type Bookshelf speakers Bookshelf speakers
    Power Range 25-200 watts Up to 85 watts
    Sensitivity 90 dB 93 dB
    Impedance 4 ohms 8 ohms
    Frequency Response 40-40k Hz 62-21k Hz
    Drivers
    Woofer Quantity 1 1
    Woofer Size 12" 5.25"
    Woofer Composition Pulp Copper-spun IMG
    Woofer Surround Material Rubber Rubber
    Tweeter Size 1" 1"
    Tweeter Type Dome Tractrix Horn
    Aimable Tweeter No No
    Midrange Driver 5.25" No
    Crossover Frequency 450Hz and 3500Hz 1660Hz
    Firing Direction front rear
    Physical Specs
    Height 636.5mm (25.1") 338.0mm (13.3")
    Width 389.6mm (15.3") 178.0mm (7")
    Depth 371.5mm (14.6") 215.0mm (8.5")
    Weight 28.60kg (62.9lbs) 5.00kg (11lbs)
    Enclosure Bass Reflex Bass Reflex
    Finish Genuine walnut veneer MDF/Wood-grain vinyl
    Available Colors Walnut Black
    Mounting Bracket No No
    Recommended Stand Height 18" 24-28"
    Grille Yes Yes
    Moisture Resistancy No No
    Connections
    Biamp Inputs Yes No
    Other
    Parts Warranty 5 Years 5 Years
    Labor Warranty 5 Years 5 Years

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