In this review, we will be comparing ES15 and C 91 II, two Passive Bookshelf speakers from Polk Audio and Jamo. Let's have a brief look at the main features
of Polk ES15 and Jamo C 91 II first before getting into our more
detailed comparison.
What size room are the Polk ES15 and Jamo C 91 II 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 Polk ES15 and Jamo C 91 II 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 ES15 and C 91 II are 2-way speakers.
| Driver |
Polk ES15 |
Jamo C 91 II |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 4-inch
|
ES15 features a 1" Terylene Soft-Dome Tweeter and 1 x 5.25" Mica-reinforced polypropylene Woofer with a Crossover frequency at 2500Hz. On the other hand, the C 91 II features a 1" Soft-Dome Tweeter and 1 x 4" Composite Woofer .
Frequency Response
ES15 has a frequency range of 44-40k Hz whereas C 91 II has a frequency range of 65-24k Hz. With a minimum frequency of 44Hz, the ES15 can go significantly deeper on the low side and provide stronger bass compared to the C 91 II's min frequency of 65Hz.
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
ES15 is a 8 ohms speaker compared to the C 91 II which has a nominal impedance of 6 ohms.
These two speakers also have different sensitivity levels. ES15 sensitivity is rated at 85 dB and the C 91 II's is rated at 86 dB. This 1 dB difference makes the Jamo C 91 II a more sensitive speaker compared to Polk ES15, 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.
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
ES15 features 5-way post type posts and C 91 II has a 5-way post type posts. None of these speakers feature bi-amping/bi-wiring.
Polk ES15's 5-Way post terminals
Jamo C 91 II's 5-way post terminals
Cabinet Type and Port Position
Both ES15 and C 91 II have rear firing ports. Rear ported speakers generally need more room between the backside of the speaker and the wall compared to sealed and front/bottom ported speakers. Placing the speakers too close to the walls may cause the bass to sound boomy.
If you are limited in space and can't get the speakers away from the backwall, check our Speakers with Front Firing Ports page.
Polk ES15 Power Port 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 Polk ES15's and Jamo C 91 II's external dimensions. Polk ES15 has external dimensions of 307.0 x 193.0 x 259.0mm ( 12-1/16 x 7-9/16 x 10-3/16inch) whereas Jamo C 91 II has external dimensions of 265.0 x 171.0 x 191.0mm ( 10.4 x 6.7 x 7.5inch) .
Polk ES15 is clearly the larger of the two speakers. Its body is 22mm wider, 42mm taller and 68mm deeper than Jamo C 91 II.
Below you can see the front view size comparison of Polk ES15 and Jamo C 91 II in scale.
Comparison image of Polk ES15 and Jamo C 91 II 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 Polk ES15 is approximately 499.9cm2 / 77.5inch2 and base area of the Jamo C 91 II is approximately 326.6cm2 / 50.6inch2. The ES15 requires 53% more surface area than the C 91 II which gives it a small disadvantage on placement in tight spaces.
Here is an another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:
Size Comparison image of Polk ES15 and Jamo C 91 II on a Media Console
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 Polk ES15 weighs 5.91kg / 13lbs and the Jamo C 91 II weighs 4.10kg / 9lbs. This makes the ES15 44% heavier than the C 91 II.
Here is a comparison of how ES15 and C 91 II's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Polk ES15?
Here are the items that are included inside the box of ES15:
2 Bookshelf loudspeakers2 Grille (attached)8 Self-adhesive rubber feetWall-mount templateOwners ManualOnline Product Registration
What's in the Box of Jamo C 91 II?
Here are the items that come with the C 91 II:
2 Bookshelf loudspeakers 2 Grilles 8 Self-adhesive rubber feet 4 Self-adhesive rubber bumpers User Manual Important Safety Instructions Warranty Information
 Nominal Impedance |
8 ohms
vs
6 ohms
|
Less selective with amplifiers |
 Woofer Size |
5.25 inches
vs
4 inches
|
Larger woofer |
| Low Frequency Response |
44 Hz
vs
65 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
24k Hz
|
Generates higher frequency |
 Price per pair* |
299USD
vs
459USD
|
costs less (*prices may change depending on the seller, location and time) |
 Sensitivity |
86 dB
vs
85 dB
|
Play louder with same amount of amplification power |
 Height |
265mm
vs
307mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
326cm2 (171x191mm)
vs
499cm2 (193x259mm)
|
Takes less floor space |
| General |
Polk Audio Signature Elite ES15 |
Jamo Concert 9 Series C 91 II |
| Brand |
Polk Audio |
Jamo |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
20-100 watts |
50-100 watts |
| Sensitivity |
85 dB |
86 dB |
| Impedance |
8 ohms |
6 ohms |
| Frequency Response |
44-40k Hz |
65-24k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
4" |
| Woofer Composition |
Mica-reinforced polypropylene |
Composite |
| Woofer Surround Material |
Butyl rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Soft-Dome |
Soft-Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2500Hz |
n/a |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
307.0mm (12.1") |
265.0mm (10.4") |
| Width |
193.0mm (7.6") |
171.0mm (6.7") |
| Depth |
259.0mm (10.2") |
191.0mm (7.5") |
| Weight |
5.91kg (13lbs) |
4.10kg (9lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF, Wood-grain vinyl |
MDF/Wood-grain |
| Available Colors |
Black,White,Walnut |
White Oak,Black Ash |
| Mounting Bracket |
Keyhole |
Keyhole |
| Recommended Stand Height |
24-28" |
28-32" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |