In this review, we will be comparing Grotto 12 and DB4S, two Powered Subwoofer speakers from MartinLogan and Bowers Wilkins. 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 B&W DB4S 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 B&W DB4S have a single woofer setup however the MartinLogan Grotto 12's woofer is 12-inch whereas the B&W DB4S features a 10-inch woofer.
Frequency Response
Grotto 12 has a frequency range of 22-120 Hz whereas DB4S has a frequency range of 10-350 Hz. With a minimum frequency of 10Hz, the DB4S can go significantly deeper on the low side and provide stronger bass compared to the Grotto 12's min frequency of 22Hz.
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
Both MartinLogan Grotto 12 and B&W DB4S have Acoustic Suspension type cabinets. 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.
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 B&W DB4S'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 B&W DB4S has external dimensions of 375.0 x 362.0 x 434.0mm (14-3/4 x 14-1/4 x 17-1/16inch).
MartinLogan Grotto 12 is clearly the larger of the two speakers. Its body is 92mm wider, 77mm taller and 20mm deeper than B&W DB4S.
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.
MartinLogan Grotto 12 needs about 31% more floor or shelf area. MartinLogan Grotto 12 is 20mm deeper, so it stands that much further out from the wall. MartinLogan Grotto 12 is 77mm 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 B&W DB4S is approximately 1571.1cm2 / 243.5inch2. The Grotto 12 requires 31% more surface area than the DB4S 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 12 weighs 37.40kg / 82.3lbs and the B&W DB4S weighs 26.05kg / 57.3lbs. This makes the Grotto 12 44% heavier than the DB4S.
Here is a comparison of how Grotto 12 and DB4S's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Woofer Size |
12 inches
vs
10 inches
|
Larger woofer |
 Passive Radiator |
2 x 12-inch
vs
None
|
Increases the bass performance |
| Low Frequency Response |
10 Hz
vs
22 Hz
|
Generates deeper bass |
 High Frequency Response |
350 Hz
vs
120 Hz
|
Generates higher frequency |
| App-Based Control |
iOS,Android
vs
None
|
Control the speaker via an app |
 Height |
375mm
vs
452mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1571cm2
vs
2061cm2
|
Takes less floor space |
 Price per pair* |
2199USD
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.
MartinLogan Grotto 12 needs about 31% more floor area. MartinLogan Grotto 12 stands 20mm further into the room. MartinLogan Grotto 12 is 77mm taller.
| General |
MartinLogan Grotto 12 |
Bowers & Wilkins DB4S |
| Brand |
MartinLogan |
Bowers Wilkins |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
1000 watts |
1000 watts |
| Frequency Response |
22-120 Hz |
10-350 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
1000-watt RMS |
n/a |
| Watts Peak (Max) |
2000-watt RMS |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
10" |
| Woofer Composition |
Aluminium |
Aerofoil |
| Woofer Surround Material |
n/a |
Rubber |
| 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") |
375.0mm (14.8") |
| Width |
454.0mm (17.9") |
362.0mm (14.3") |
| Depth |
454.0mm (17.9") |
434.0mm (17.1") |
| Weight |
37.40kg (82.3lbs) |
26.05kg (57.3lbs) |
| Enclosure |
Acoustic Suspension |
Acoustic Suspension |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
|
2 Years |
| Labor Warranty |
|
2 Years |
No single best subwoofer here. Your room, where the box can physically go, and whether this is mainly for films or mainly for music will settle it long before the specs do.
| Area | Better | Why |
|---|
| Bass depth | B | B&W DB4S goes deeper - 10Hz against 22Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Amplifier power | evenly matched | Much the same amplifier (1000W vs 1000W RMS) - under 1dB apart. |
| Driver area | A | MartinLogan Grotto 12 moves more air: 12" against 10" is 1.44x the cone area, not the 1.2x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | evenly matched | Both are sealed designs, so they roll off in much the same way. |
| 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 | B&W DB4S is about 37% 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 | evenly matched | Priced within a few per cent of each other. |
A MartinLogan Grotto 12 B B&W DB4S
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?
MartinLogan Grotto 12 has the edge on paper, though not by much. The "depends" rows are more likely to decide this than the score is. 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. If placement is the constraint - a corner, behind a sofa, under a desk - B&W DB4S is the one that will actually go there, and a well-placed small subwoofer beats a badly-placed big one every time.
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.