In this review, we will be comparing S15 and TSi100, two Passive Bookshelf speakers by Polk Audio.
Let's have a brief look at the main features
of Polk S15 and Polk TSi100 first before getting into our more
detailed comparison.
| Key Specs | Polk S15 | Polk TSi100 |
|---|
| Brand | Polk Audio
United States · founded 1972 | Polk Audio
United States · founded 1972 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" Dome | 1" Dome |
|---|
| Woofer | 5.25" Mica-reinforced polypropylene | 5.25" Organic Fiber |
|---|
| Frequency response | 50-40k Hz | 61-24k Hz |
|---|
| Sensitivity | 88 dB | 89 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 20-100 watts | 20-100 watts |
|---|
| Weight | 5.90kg / 13lbs | 4.53kg / 10lbs |
|---|
| Dimensions (H x W x D) | 12.0" x 7.4" x 10.2"
304.8 x 190.0 x 260.4mm | 11.0" x 7.0" x 10.1"
279.4 x 177.8 x 259.0mm |
|---|
What size room are the Polk S15 and Polk TSi100 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* |
Polk S15 |
Polk TSi100 |
| Near-field |
Average |
Average |
| Small Room |
Good |
Good |
| Mid-size Room |
Average |
Average |
| Large Room |
Poor |
Poor |
| Very Large Room |
Bad |
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.
Drivers
Both S15 and TSi100 are 2-way speakers.
Polk S15Polk TSi100
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Polk S15 |
Polk TSi100 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
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 TSi100 features a 1" Dome Tweeter and 1 x 5.25" Organic Fiber Woofer with a Crossover frequency at 2500Hz.
Frequency Response
S15 has a frequency range of 50-40k Hz whereas TSi100 has a frequency range of 61-24k Hz. With a minimum frequency of 50Hz, the S15 can go significantly deeper on the low side and provide stronger bass compared to the TSi100's min frequency of 61Hz.
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
S15 and TSi100 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. S15 sensitivity is rated at 88 dB and the TSi100's is at 89 dB. This 1 dB difference makes the Polk TSi100 a more sensitive speaker compared to Polk S15, 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.
S15 and TSi100 have the same power range of 20-100 watts.
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
S15 features Pair of 5-way Binding Posts - Gold-Plated type posts and TSi100 has a Pair of 5-way Binding Posts - Gold-Plated type posts. None of these speakers feature bi-amping/bi-wiring.
Cabinet Type and Port Position
Both S15 and TSi100 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 Polk S15's and Polk TSi100'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 Polk TSi100 has external dimensions of 279.4 x 177.8 x 259.0mm (11.0 x 7.0 x 10.1inch).
Polk S15 is clearly the larger of the two speakers. Its body is 12.2mm wider, 25.4mm taller and 1.4mm deeper than Polk TSi100.
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 Polk TSi100 is approximately 460.5cm2 / 71.4inch2. The S15 requires 7% more surface area than the TSi100 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 Polk S15 weighs 5.90kg / 13lbs and the Polk TSi100 weighs 4.53kg / 10lbs. This makes the S15 30% heavier than the TSi100.
Here is a comparison of how S15 and TSi100'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 loudspeakers
- 2 Grille (attached)
- 8 Self-adhesive rubber feet
- Wall-mount template
- Owners Manual
- Online Product Registration
What's in the Box of Polk TSi100?
Here are the items that come with the TSi100:
- 2 Black bookshelf speakers
- Detachable cloth grille (installed)
- 8 Self-adhesive rubber feet
- Owner's Manual
- Wall-Mount template
- Online registration sheet
- Polk Audio product brochure
 Low Frequency Response |
50 Hz
vs
61 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
24k Hz
|
Generates higher frequency |
 Sensitivity |
89 dB
vs
88 dB
|
Play louder with same amount of amplification power |
 Height |
279mm
vs
304mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
460cm2
vs
494cm2
|
Takes less floor space |
 Price per pair* |
149USD
vs
259USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Polk Audio Signature S15 |
Polk Audio TSi100 |
| Brand |
Polk Audio |
Polk Audio |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
20-100 watts |
20-100 watts |
| Sensitivity |
88 dB |
89 dB |
| Impedance |
8 ohms |
8 ohms |
| Frequency Response |
50-40k Hz |
61-24k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
5.25" |
| Woofer Composition |
Mica-reinforced polypropylene |
Organic Fiber |
| Woofer Surround Material |
Butyl rubber |
Butyl Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2500Hz |
2500Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
304.8mm (12") |
279.4mm (11") |
| Width |
190.0mm (7.5") |
177.8mm (7") |
| Depth |
260.4mm (10.3") |
259.0mm (10.2") |
| Weight |
5.90kg (13lbs) |
4.53kg (10lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
Meddite MDF |
Wood-grain vinyl |
| Available Colors |
Black, Walnut, Brown Walnut |
Black, Cherry |
| Mounting Bracket |
Keyhole |
Keyhole |
| Recommended Stand Height |
24-30" |
16-30" |
| 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 |
These sit in different price classes - Polk S15 costs roughly 1.7x what Polk TSi100 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 | A | Polk S15 digs deeper - 50Hz against 61Hz. |
| Amplifier needs | evenly matched | Similar sensitivity (88dB vs 89dB) - both want much the same power. |
| Headroom | evenly matched | Similar power handling (100W vs 100W). |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Price | B | Polk TSi100 is cheaper - $149 against $259, about 42% less; arguably a different class. |
A Polk S15 B Polk TSi100
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 ahead, but only on 1 of the measured areas, and it costs about 74% more. That is a lot of money for a narrow margin on paper - Polk TSi100 looks like the sensible buy unless something else about the Polk S15 appeals to you. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 61Hz anyway, which makes the cheaper Polk TSi100 much easier to justify. Think about the whole system, not just the speakers: the roughly $110 saved by taking the cheaper pair would buy a subwoofer or a better amplifier, and either usually does more for the sound than the difference between these two.
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.