In this review, we will be comparing Model Three and ES20, two Passive Bookshelf speakers from KLH and Polk Audio.
Let's have a brief look at the main features
of KLH Model Three and Polk ES20 first before getting into our more
detailed comparison.
| Key Specs | KLH Model Three | Polk ES20 |
|---|
| Brand | KLH
United States · founded 1957 | Polk Audio
United States · founded 1972 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" | 1" Soft-Dome |
|---|
| Woofer | 8" Pulp-Paper Cone | 6.5" Mica-reinforced polypropylene |
|---|
| Frequency response | 46-20k Hz | 41-40k Hz |
|---|
| Sensitivity | 88 dB | 86 dB |
|---|
| Impedance | 6 ohms | 8 ohms |
|---|
| Power range | 30-150 watts | 20-125 watts |
|---|
| Weight | 13.20kg / 29lbs | 7.73kg / 17lbs |
|---|
| Dimensions (H x W x D) | 19.0" x 12.25" x 10.5"
482.0 x 311.0 x 267.0mm | 14-3/4" x 8-9/16" x 13-13/16"
375.0 x 218.0 x 351.0mm |
|---|
What size room are the KLH Model Three and Polk ES20 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* |
KLH Model Three |
Polk ES20 |
| Near-field |
Poor |
Poor |
| Small Room |
Average |
Average |
| Mid-size Room |
Good |
Good |
| Large Room |
Average |
Average |
| Very Large Room |
Poor |
Poor |
(* 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.)
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both Model Three and ES20 are 2-way speakers.
KLH Model ThreePolk ES20
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
KLH Model Three |
Polk ES20 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 8-inch
|
1 x 6.5-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 ES20 features a 1" Terylene Soft-Dome Tweeter and 1 x 6.5" Mica-reinforced polypropylene Woofer with a Crossover frequency at 2500Hz.
Frequency Response
Model Three has a frequency range of 46-20k Hz whereas ES20 has a frequency range of 41-40k Hz. With a minimum frequency of 41Hz, the ES20 can go significantly deeper on the low side and provide stronger bass compared to the Model Three's min frequency of 46Hz.
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.
Impedance and Sensitivity
Model Three is a 6 ohms speaker compared to the ES20 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 ES20's is rated at 86 dB. This 2 dB difference makes the KLH Model Three a more sensitive speaker compared to Polk ES20, 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. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
Model Three can handle a max power of 150 watts RMS, whereas ES20 has a max power handling value of 125 watts RMS, 25 watts less than the Model Three.
Note that higher power handling does not make a speaker louder: that depends mainly on
sensitivity and impedance. The calculator below shows how loud each of these actually plays
on a real amplifier.
Which plays louder on your amplifier?
Starting with a popular amplifier - change it to the one you own, or any you are
considering, and watch both numbers move.
Input Type and Bi-Amping / Bi-Wiring
Model Three features 5-Way post type posts and ES20 has a 5-Way post type posts. None of these speakers feature bi-amping/bi-wiring.
KLH Model Three's Binding post terminals
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 KLH Model Three's and Polk ES20'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 Polk ES20 has external dimensions of 375.0 x 218.0 x 351.0mm (14-3/4 x 8-9/16 x 13-13/16inch).
Polk ES20 is 93mm narrower and 107mm shorter than KLH Model Three but it is also 84mm deeper.
Size, drawn to scale
Both speakers and both views share one scale, so everything here is directly comparable. Hover a box for its dimensions.
One scale for both, standing on the same surface and pushed back to the same wall, so the deeper one visibly sticks out further.
KLH Model Three needs about 9% more floor or shelf area. Polk ES20 is 84mm deeper, so it stands that much further out from the wall. KLH Model Three is 107mm taller.
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 Polk ES20 is approximately 765.2cm2 / 118.6inch2. The Model Three requires 9% more surface area than the ES20 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 Polk ES20 weighs 7.73kg / 17lbs. This makes the Model Three 71% heavier than the ES20.
Here is a comparison of how Model Three and ES20'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 loudspeaker
- Riser base
- Grille
- Owners Manual
What's in the Box of Polk ES20?
Here are the items that come with the ES20:
- 2 Bookshelf loudspeakers
- 2 Grille (attached)
- 8 Self-adhesive rubber feet
- Owners Manual
- Online Product Registration
 Max Input Power |
150 watts
vs
125 watts
|
Handle more power from your amplifier |
 Sensitivity |
88 dB
vs
86 dB
|
Play louder with same amount of amplification power |
 Woofer Size |
8 inches
vs
6.5 inches
|
Larger woofer |
 Nominal Impedance |
8 ohms
vs
6 ohms
|
Less selective with amplifiers |
|
Low Frequency Response |
41 Hz
vs
46 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
20k Hz
|
Generates higher frequency |
 Height |
375mm
vs
482mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
765cm2
vs
830cm2
|
Takes less floor space |
 Price per pair* |
399USD
vs
2000USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
KLH Model Three |
Polk Audio Signature Elite ES20 |
| Brand |
KLH |
Polk Audio |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
30-150 watts |
20-125 watts |
| Sensitivity |
88 dB |
86 dB |
| Impedance |
6 ohms |
8 ohms |
| Impedance |
3.7 ohms |
n/a |
| Frequency Response |
46-20k Hz |
41-40k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
6.5" |
| Woofer Composition |
Pulp-Paper Cone |
Mica-reinforced polypropylene |
| Woofer Surround Material |
Rubber |
Butyl rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
n/a |
Soft-Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
1600Hz |
2500Hz |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
482.0mm (19") |
375.0mm (14.8") |
| Width |
311.0mm (12.2") |
218.0mm (8.6") |
| Depth |
267.0mm (10.5") |
351.0mm (13.8") |
| Weight |
13.20kg (29lbs) |
7.73kg (17lbs) |
| Enclosure |
Acoustic Suspension |
Bass Reflex |
| Finish |
MDF/Wood Veneer |
MDF, Wood-grain vinyl |
| Available Colors |
English Walnut, West African Mahogany |
Black,White,Walnut |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
n/a |
22-26" |
| 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 |
These sit in different price classes - KLH Model Three costs roughly 5x what Polk ES20 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 | B | Polk ES20 digs deeper - 41Hz against 46Hz. A subwoofer would even that out. |
| Amplifier needs | A | KLH Model Three is more sensitive (88dB vs 86dB), so it goes louder on the same amplifier. |
| Amplifier match | B | Polk ES20 is the easier load at 8 ohms. |
| Headroom | evenly matched | Similar power handling (150W vs 125W). |
| Size | depends | Polk ES20 is easier to place; KLH Model Three is bigger, which usually goes with fuller bass. Your room decides. |
| Cabinet | depends | Sealed vs Ported. Sealed is tighter and happier near a wall; ported digs lower but wants space behind it. |
| Expandability | depends | Neither adds bi-amping, a sub output or height drivers. Polk ES20 sits in a wider range (12 models), so a matched surround system is easier later. |
| Price | B | Polk ES20 is cheaper - $399 against $2,000, about 80% less; arguably a different class. |
A KLH Model Three B Polk ES20
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?
Polk ES20 has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 46Hz anyway, so judge these on the other rows instead. If your amplifier is modest, vintage or valve-based, KLH Model Three is the safer partner - the other will want more current or more watts to sound its best.
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.