In this review, we will be comparing Grotto 12 and SW-15, two Powered Subwoofer speakers from MartinLogan and Wharfedale. Being Powered subwoofers, they both have built-in amplifiers so you don't need an external power amp or an integrated amp to power them. Let's have a brief look at the main features of MartinLogan Grotto 12 and Wharfedale SW-15 first before getting into our more detailed comparison.
The sections below take each area in turn: driver and amplifier, frequency response, physical size and connectivity.
Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.Both MartinLogan Grotto 12and Wharfedale SW-15 have a single woofer setup however the MartinLogan Grotto 12's woofer is 12-inch whereas the Wharfedale SW-15 features a 15-inch woofer.
Frequency Response
Grotto 12 has a frequency range of 22-120 Hz whereas SW-15 has a frequency range of 30-120 Hz. With a minimum frequency of 22Hz, the Grotto 12 can go significantly deeper on the low side and provide stronger bass compared to the SW-15's min frequency of 30Hz.
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 Subwoofer class in our database.
Low Frequency
Subwoofer Speakers
High Frequency
Subwoofer Speakers
Cabinet Type
The MartinLogan Grotto 12 has a Acoustic Suspension type cabinet. Acoustic Suspension aka Sealed type subwoofers have enclosures that are sealed hence no ports or holes exists on the cabinet. Sealed designs helps to provide more accurate and tight bass responses compared to ported designs. On the other hand the Wharfedale SW-15 have Bass Reflex type enclosure. Bass Reflex type subwoofers (aka Ported, Vented or Reflex Port) have enclosures that uses a port, hole or vent cut into the cabinet. Ported designs are generally more efficient than the Sealed designs.
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 MartinLogan Grotto 12's and Wharfedale SW-15's external dimensions. MartinLogan Grotto 12 has external dimensions of 452.0 x 454.0 x 454.0mm (17-13/16 x 17-7/8 x 17-7/8inch) whereas Wharfedale SW-15 has external dimensions of 570.0 x 493.0 x 615.0mm (22-7/16inch x 19-3/8inch x 24-3/16inch).
Wharfedale SW-15 is clearly the larger of the two speakers. Its body is 39mm wider, 118mm taller and 161mm deeper than MartinLogan Grotto 12.
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.
Wharfedale SW-15 needs about 47% more floor or shelf area. Wharfedale SW-15 is 161mm deeper, so it stands that much further out from the wall. Wharfedale SW-15 is 118mm 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 MartinLogan Grotto 12 is approximately 2061.2cm2 / 319.5inch2 and base area of the Wharfedale SW-15 is approximately 3032.0cm2 / 470.0inch2. The Grotto 12 requires 32% less surface area than the SW-15 which gives it a small advantage on placement in tight spaces.
Weight Comparison The weight of a subwoofer may become an important factor if you need to move and reposition the unit often to find the optimal positioning, also known as 'Subwoofer Crawling'. The MartinLogan Grotto 12 weighs 37.40kg / 82.3lbs and the Wharfedale SW-15 weighs 31.57kg / 69.5lbs. This makes the Grotto 12 18% heavier than the SW-15.
Here is a comparison of how Grotto 12 and SW-15's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Low Frequency Response |
22 Hz
vs
30 Hz
|
Generates deeper bass |
 Passive Radiator |
2 x 12-inch
vs
None
|
Increases the bass performance |
 Height |
452mm
vs
570mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
2061cm2
vs
3032cm2
|
Takes less floor space |
| Woofer Size |
15 inches
vs
12 inches
|
Larger woofer |
 Price per pair* |
1199USD
vs
2300USD
|
costs less (*prices may change depending on the seller, location and time) |
Size, drawn to scale
Both subwoofers 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 floor and pushed back to the same wall, so the bigger one visibly takes more of the room.
Wharfedale SW-15 needs about 47% more floor area. Wharfedale SW-15 stands 161mm further into the room. Wharfedale SW-15 is 118mm taller.
| General |
MartinLogan Grotto 12 |
Wharfedale SW-15 |
| Brand |
MartinLogan |
Wharfedale |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
1000 watts |
400 watts |
| Frequency Response |
22-120 Hz |
30-120 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
1000-watt RMS |
400-watt RMS |
| Watts Peak (Max) |
2000-watt RMS |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
15" |
| Woofer Composition |
Aluminium |
Paper |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
35–120Hz |
n/a |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
452.0mm (17.8") |
570.0mm (22.4") |
| Width |
454.0mm (17.9") |
493.0mm (19.4") |
| Depth |
454.0mm (17.9") |
615.0mm (24.2") |
| Weight |
37.40kg (82.3lbs) |
31.57kg (69.5lbs) |
| Enclosure |
Acoustic Suspension |
Bass Reflex |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
|
3 Years |
| Labor Warranty |
|
3 Years |
A sealed subwoofer against a ported one. That is the most consequential line on this page: it decides how the bass rolls off, how it behaves in a small room, and how much output you get for the size of the box.
| Area | Better | Why |
|---|
| Bass depth | A | MartinLogan Grotto 12 goes deeper - 22Hz against 30Hz. That gap covers the lowest notes of a five-string bass and a concert bass drum. |
| Amplifier power | A | MartinLogan Grotto 12 has the bigger amplifier - 1000W against 400W RMS, about 4dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | B | Wharfedale SW-15 moves more air: 15" against 12" is 1.56x the cone area, not the 1.25x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | depends | MartinLogan Grotto 12 is sealed - a sealed box rolls off gently and is usually the easier one to integrate in a small or awkward room; Wharfedale SW-15 is ported - a ported box gives more output low down for its size, at the cost of a steeper roll-off below tuning. Neither is better in the abstract; ported tends to suit films and sealed tends to suit music, and both generalisations have exceptions. |
| Speaker-level inputs | A | MartinLogan Grotto 12 takes a speaker-level connection as well as line level. That is what lets it work with an integrated amplifier or a vintage receiver that has no subwoofer output at all. |
| Cabinet size | depends | MartinLogan Grotto 12 is about 46% smaller by volume. In a subwoofer that is a real trade rather than a preference: box volume is how you get output low down without a bigger amplifier. |
| Price | B | Wharfedale SW-15 costs less - $1,199 against $2,300, about 48% less. |
A MartinLogan Grotto 12 B Wharfedale SW-15
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 subwoofers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
The usual trade-off: MartinLogan Grotto 12 measures better, Wharfedale SW-15 costs about 48% less. In a normal room, placement will make a bigger difference than the gap between these two. Films or music? If this is mainly a home cinema, Wharfedale SW-15 will hit harder for the money; if it is mainly for music in a normal-sized room, MartinLogan Grotto 12 is usually the easier one to make sound right. Check your amplifier first: if it has no subwoofer or preamp output, MartinLogan Grotto 12 is the only one of these two you can connect at all.
One thing outweighs everything above: where the subwoofer stands. Room modes can add or remove 10dB or more at a given seat, which is far larger than any difference on this page. Before spending more, try the sub in two or three positions - the crawl test, where you put it in the listening seat and crawl the room to find where the bass sounds best, costs nothing and usually beats an upgrade.