In this review, we will be comparing Grotto 15 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 15 and Wharfedale SW-15 first before getting into our more detailed comparison.
In the following sections, we will get into details in order to better understand how the MartinLogan Grotto 15 and Wharfedale SW-15 compare and hopefully end up with enough arguments to decide which one of these subwoofers is the better choice for you.
**This post contains affiliate links, and I will be compensated if you make a purchase after clicking through my links. As an Amazon Associate I earn from qualifying purchases.
Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.MartinLogan Grotto 15and Wharfedale SW-15 have the same driver set up: Both subwoofers have 1 x 15" drivers.
Frequency Response
Grotto 15 has a frequency range of 20-120 Hz whereas SW-15 has a frequency range of 30-120 Hz. With a minimum frequency of 20Hz, the Grotto 15 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 15 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
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 MartinLogan Grotto 15's and Wharfedale SW-15's external dimensions. MartinLogan Grotto 15 has external dimensions of 522.0 x 554.0 x 554.0mm ( 20-9/16 x 21-13/16 x 21-13/16inch) 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 ) .
MartinLogan Grotto 15 is 48mm shorter and 61mm less deeper than Wharfedale SW-15 but it is also 61mm 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 MartinLogan Grotto 15 is approximately 3069.2cm2 / 475.7inch2 and base area of the Wharfedale SW-15 is approximately 3032.0cm2 / 470.0inch2. The Grotto 15 requires 1% more surface area than the SW-15 which gives it a small disadvantage 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 15 weighs 53.50kg / 117.7lbs and the Wharfedale SW-15 weighs 31.57kg / 69.5lbs. This makes the Grotto 15 69% heavier than the SW-15.
Here is a comparison of how Grotto 15 and SW-15's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Low Frequency Response |
20 Hz
vs
30 Hz
|
Generates deeper bass |
 Passive Radiator |
2 x 15-inch
vs
None
|
Increases the bass performance |
 Height |
522mm
vs
570mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
3032cm2
vs
3069cm2
|
Takes less floor space |
 Price per pair* |
1199USD
vs
2800USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
MartinLogan Grotto 15 |
Wharfedale SW-15 |
| Brand |
MartinLogan |
Wharfedale |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
1000 watts |
400 watts |
| Frequency Response |
20-120 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 |
15" |
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 |
522.0mm (20.6") |
570.0mm (22.4") |
| Width |
554.0mm (21.8") |
493.0mm (19.4") |
| Depth |
554.0mm (21.8") |
615.0mm (24.2") |
| Weight |
53.50kg (117.7lbs) |
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 |