In this review, we will be comparing S15 and Uni-Fi BS U5 Slim, two Passive Bookshelf speakers from Polk Audio and ELAC. Let's have a brief look at the main features
of Polk S15 and ELAC Uni-Fi BS U5 Slim first before getting into our more
detailed comparison.
What size room are the Polk S15 and ELAC Uni-Fi BS U5 Slim 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 S15 and ELAC Uni-Fi BS U5 Slim 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
One of the fundamental differences between these two speakers is that S15 is a 2-way design whereas the Uni-Fi BS U5 Slim is a 3-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 |
Polk S15 |
ELAC Uni-Fi BS U5 Slim |
Driver Setup
|
2-way
|
3-way
|
Tweeter
|
1-inch
|
1-inch
|
Midrange
|
- |
1 x 4-inch |
Woofer
|
1 x 5.25-inch
|
1 x 5.25-inch
|
S15 features a 1" Terylene Dome Tweeter and 1 x 5.25" Mica-reinforced polypropylene Woofer with a Crossover frequency at 2500Hz. On the other hand, the Uni-Fi BS U5 Slim features a 1" soft dome Tweeter , a 4" Midrange and 1 x 5.25" Aluminum Woofer .
Frequency Response
S15 has a frequency range of 50-40k Hz whereas Uni-Fi BS U5 Slim has a frequency range of 46-25k Hz. With a minimum frequency of 46Hz, the Uni-Fi BS U5 Slim can go slightly deeper then the S15's min frequency of 50Hz.
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
S15 is a 8 ohms speaker compared to the Uni-Fi BS U5 Slim which has a nominal impedance of 4 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 Uni-Fi BS U5 Slim can provide this impedance level.
These two speakers also have different sensitivity levels. S15 sensitivity is rated at 88 dB and the Uni-Fi BS U5 Slim's is rated at 85 dB. This 3 dB difference makes the Polk S15 a more sensitive speaker compared to ELAC Uni-Fi BS U5 Slim, 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.
S15 can handle a max power of 140 watts RMS from the amp the whereas S15 has a max power handling value of 100 watts RMS , 40 watts less than the Uni-Fi BS U5 Slim.
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
S15 features Post type posts and Uni-Fi BS U5 Slim has a Post type posts. None of these speakers feature bi-amping/bi-wiring.
Cabinet Type and Port Position
Both S15 and Uni-Fi BS U5 Slim 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.
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 S15's and ELAC Uni-Fi BS U5 Slim's external dimensions. Polk S15 has external dimensions of 304.8 x 190.0 x 260.4mm ( 12.0 x 7.4 x 10.2inch) whereas ELAC Uni-Fi BS U5 Slim has external dimensions of 340.0 x 180.0 x 328.0mm ( 13-3/8 x 7-1/16 x 12-7/8inch) .
Polk S15 is 35.2mm shorter and 67.6mm less deeper than ELAC Uni-Fi BS U5 Slim but it is also 10mm wider.
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 S15 is approximately 494.8cm2 / 76.7inch2 and base area of the ELAC Uni-Fi BS U5 Slim is approximately 590.4cm2 / 91.5inch2. The S15 requires 16% less surface area than the Uni-Fi BS U5 Slim which gives it a small advantage 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 Polk S15 weighs 5.90kg / 13lbs and the ELAC Uni-Fi BS U5 Slim weighs 7.50kg / 16.5lbs. This makes the Uni-Fi BS U5 Slim 27% heavier than the S15.
Here is a comparison of how S15 and Uni-Fi BS U5 Slim'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 S15?
Here are the items that are included inside the box of S15:
2 Bookshelf loudspeakers2 Grille (attached)8 Self-adhesive rubber feetWall-mount templateOwners ManualOnline Product Registration
What's in the Box of ELAC Uni-Fi BS U5 Slim?
Here are the items that come with the Uni-Fi BS U5 Slim:
2 Bookshelf loudspeakers 2 Grilles Operating Instructions
Sensitivity |
88 dB
vs
85 dB
|
Play louder with same amount of amplification power |
Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
High Frequency Response |
40k Hz
vs
25k Hz
|
Generates higher frequency |
Mounting Bracket |
Yes
vs
No
|
Allows mounting on walls |
Height |
304mm
vs
340mm
|
Easier to fit in smaller spaces |
Base Surface Area |
494cm2 (190x260mm)
vs
590cm2 (180x328mm)
|
Takes less floor space |
Price per pair* |
259USD
vs
735USD
|
costs less (*prices may change depending on the seller, location and time) |
Max Input Power |
140 watts
vs
100 watts
|
Handle more power from your amplifier |
Driver Setup |
3-way
vs
2-way
|
Have a dedicated mid-range driver |
Low Frequency Response |
46 Hz
vs
50 Hz
|
Generates deeper bass |
General |
Polk Audio Signature S15 |
ELAC Uni-Fi BS U5 Slim |
Brand |
Polk Audio |
ELAC |
Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
Power Range |
20-100 watts |
40-140 watts |
Sensitivity |
88 dB |
85 dB |
Impedance |
8 ohms |
4 ohms |
Frequency Response |
50-40k Hz |
46-25k Hz |
Drivers |
|
|
Woofer Quantity |
1 |
1 |
Woofer Size |
5.25" |
5.25" |
Woofer Composition |
Mica-reinforced polypropylene |
Aluminum |
Woofer Surround Material |
Butyl rubber |
Rubber |
Tweeter Size |
1" |
1" |
Tweeter Type |
Dome |
soft dome |
Aimable Tweeter |
No |
No |
Midrange Driver |
No |
4" |
Crossover Frequency |
2500Hz |
n/a |
Firing Direction |
rear |
rear |
Physical Specs |
|
|
Height |
304.8mm (12") |
340.0mm (13.4") |
Width |
190.0mm (7.5") |
180.0mm (7.1") |
Depth |
260.4mm (10.3") |
328.0mm (12.9") |
Weight |
5.90kg (13lbs) |
7.50kg (16.5lbs) |
Enclosure |
Bass Reflex |
Bass Reflex |
Finish |
Meddite MDF |
MDF/Vinyl |
Available Colors |
Black, Walnut, Brown Walnut |
Black |
Mounting Bracket |
Keyhole |
No |
Recommended Stand Height |
24-30" |
24-31" |
Grille |
Yes |
Yes |
Moisture Resistancy |
No |
No |
Connections |
|
|
Biamp Inputs |
No |
No |
Other |
|
|
Parts Warranty |
5 Years |
3 Years |
Labor Warranty |
5 Years |
3 Years |