In this review, we will be comparing 3020i and S15, two Passive Bookshelf speakers from Q Acoustics and Polk Audio.
Let's have a brief look at the main features
of Q Acoustics 3020i and Polk S15 first before getting into our more
detailed comparison.
| Key Specs | Q Acoustics 3020i | Polk S15 |
|---|
| Brand | Q Acoustics
United Kingdom · founded 2006 | Polk Audio
United States · founded 1972 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 0.9" decoupled | 1" Dome |
|---|
| Woofer | 5" Coated paper | 5.25" Mica-reinforced polypropylene |
|---|
| Frequency response | 64-30k Hz | 50-40k Hz |
|---|
| Sensitivity | 88 dB | 88 dB |
|---|
| Impedance | 6 ohms | 8 ohms |
|---|
| Power range | 25-75 watts | 20-100 watts |
|---|
| Weight | 4.80kg / 10.6lbs | 5.90kg / 13lbs |
|---|
| Dimensions (H x W x D) | 10.9" x 6.6" x 11.1"
278.0 x 170.0 x 282.0mm | 12.0" x 7.4" x 10.2"
304.8 x 190.0 x 260.4mm |
|---|
What size room are the Q Acoustics 3020i and Polk S15 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* |
Q Acoustics 3020i |
Polk S15 |
| Near-field |
Good |
Average |
| Small Room |
Good |
Good |
| Mid-size Room |
Average |
Average |
| Large Room |
Poor |
Poor |
| Very Large Room |
No way |
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.)
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
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through our links. As an Amazon Associate I earn from qualifying purchases.
Drivers
Both 3020i and S15 are 2-way speakers.
Q Acoustics 3020iPolk S15
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Q Acoustics 3020i |
Polk S15 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
0.9-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5-inch
|
1 x 5.25-inch
|
3020i features a 0.9" decoupled Tweeter and 1 x 5" Coated paper Woofer with a Crossover frequency at 2400Hz. On the other hand, the S15 features a 1" Terylene Dome Tweeter and 1 x 5.25" Mica-reinforced polypropylene Woofer with a Crossover frequency at 2500Hz.
Frequency Response
3020i has a frequency range of 64-30k Hz whereas S15 has a frequency range of 50-40k Hz. With a minimum frequency of 50Hz, the S15 can go significantly deeper on the low side and provide stronger bass compared to the 3020i's min frequency of 64Hz.
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
3020i is a 6 ohms speaker compared to the S15 which has a nominal impedance of 8 ohms.
On the other hand, they have the same sensitivity of 88 dBdB.
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.
S15 can handle a max power of 100 watts RMS, whereas 3020i has a max power handling value of 75 watts RMS, 25 watts less than the S15.
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
3020i features Pair of Binding Posts - Gold Plated type posts and S15 has a Pair of Binding Posts - Gold Plated type posts. None of these speakers feature bi-amping/bi-wiring.
Cabinet Type and Port Position
Both 3020i and S15 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
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 Q Acoustics 3020i's and Polk S15's external dimensions. Q Acoustics 3020i has external dimensions of 278.0 x 170.0 x 282.0mm (10.9 x 6.6 x 11.1inch) whereas Polk S15 has external dimensions of 304.8 x 190.0 x 260.4mm (12.0 x 7.4 x 10.2inch).
Q Acoustics 3020i is 20mm narrower and 26.8mm shorter than Polk S15 but it is also 21.6mm deeper.
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 Q Acoustics 3020i is approximately 479.4cm2 / 74.3inch2 and base area of the Polk S15 is approximately 494.8cm2 / 76.7inch2. The 3020i requires 3% less surface area than the S15 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 Q Acoustics 3020i weighs 4.80kg / 10.6lbs and the Polk S15 weighs 5.90kg / 13lbs. This makes the S15 23% heavier than the 3020i.
Here is a comparison of how 3020i and S15's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Q Acoustics 3020i?
Here are the items that are included inside the box of 3020i:
- 2 x 3020i bookshelf speakers
- 2 x Foam Bungs
- 2 x Speaker Grilles
- 1 x User Manual
- 1 x Handling Gloves
- 8 x Rubber Speaker Grips
What's in the Box of Polk S15?
Here are the items that come with the S15:
- 2 Bookshelf loudspeakers
- 2 Grille (attached)
- 8 Self-adhesive rubber feet
- Wall-mount template
- Owners Manual
- Online Product Registration
 Height |
278mm
vs
304mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
479cm2
vs
494cm2
|
Takes less floor space |
 Max Input Power |
100 watts
vs
75 watts
|
Handle more power from your amplifier |
 Nominal Impedance |
8 ohms
vs
6 ohms
|
Less selective with amplifiers |
 Woofer Size |
5.25 inches
vs
5 inches
|
Larger woofer |
|
Low Frequency Response |
50 Hz
vs
64 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
30k Hz
|
Generates higher frequency |
 Mounting Bracket |
Yes
vs
No
|
Allows mounting on walls |
 Price per pair* |
259USD
vs
399USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Q Acoustics 3020i |
Polk Audio Signature S15 |
| Brand |
Q Acoustics |
Polk Audio |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
25-75 watts |
20-100 watts |
| Sensitivity |
88 dB |
88 dB |
| Impedance |
6 ohms |
8 ohms |
| Impedance |
4 ohms |
n/a |
| Frequency Response |
64-30k Hz |
50-40k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5" |
5.25" |
| Woofer Composition |
Coated paper |
Mica-reinforced polypropylene |
| Woofer Surround Material |
Rubber |
Butyl rubber |
| Tweeter Size |
0.9" |
1" |
| Tweeter Type |
decoupled |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2400Hz |
2500Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
278.0mm (10.9") |
304.8mm (12") |
| Width |
170.0mm (6.7") |
190.0mm (7.5") |
| Depth |
282.0mm (11.1") |
260.4mm (10.3") |
| Weight |
4.80kg (10.6lbs) |
5.90kg (13lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
n/a |
Meddite MDF |
| Available Colors |
Walnut, Black, White, Grey |
Black, Walnut, Brown Walnut |
| Mounting Bracket |
No |
Keyhole |
| Recommended Stand Height |
n/a |
24-30" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
4 Years |
5 Years |
| Labor Warranty |
4 Years |
5 Years |
No single best speaker here - they are built to different priorities, and the right one depends on your room, your amplifier and what you listen to.
| Area | Better | Why |
|---|
| Bass | B | Polk S15 digs deeper - 50Hz against 64Hz. |
| Amplifier needs | evenly matched | Similar sensitivity (88dB vs 88dB) - both want much the same power. |
| Amplifier match | B | Polk S15 is the easier load at 8 ohms. |
| Headroom | B | Polk S15 takes more power (100W vs 75W) - more in hand in a big room. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Price | B | Polk S15 is cheaper - $259 against $399, about 35% less. |
A Q Acoustics 3020i B Polk S15
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 S15 is the easier recommendation: it leads on most of the measured areas and costs less. Take Q Acoustics 3020i if its size, looks or fit in your room suit you better. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 64Hz anyway, so judge these on the other rows instead. Match it to your room: we rate Q Acoustics 3020i the better fit for near-field listening; elsewhere the two are rated the same.
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.