Grotto 15 is a Sealed type Powered Subwoofer by MartinLogan with a frequency range of 20-120 Hz. It was released in 2026. It features 1 x 15" Aluminium Woofer, and powered by a Class D 1000 watts amplifier. Grotto 15 also employs 2 x 15-inch passive radiators.
A sealed subwoofer with a 15 inch woofer plus 2 passive radiators on a 1000 W RMS (2000 W peak) Class D amplifier, 20 Hz to 120 Hz. Anthem Room Correction is built in. Grotto pairs one driven woofer with two passive radiators in a sealed cabinet, which buys the output of a much larger box without a port.
Grotto 15 is a member of MartinLogan's Grotto series of Powered subwoofers. Below you can see the main specs of these subwoofers as well as review and comparison links.
MartinLogan Grotto Series Subwoofers
Frequency Response
Where should the crossover go? → · What will your room do to this bass? →
MartinLogan Grotto 15 has a Frequency response range of 20-120 Hz. Thanks to its 1 x 15-inch driver and 1000 watts RMS (2000 watts MAX) amplifier, the Grotto 15 can go as low as 20 Hz which means you can get a Full range (20Hz-20kHz) listening experience when coupled with almost any loudspeaker in the market.
Here we have a comparison of how Grotto 15's Low and High frequency values compare with the average, max and min Low and High frequency values in its class.
Low Frequency
Powered Subwoofers
High Frequency
Subwoofer Speakers
Among all subwoofers in our database with a max MSRP price of 3000$, these are the 5 Powered Subwoofer models that can reach deeper bass levels than the MartinLogan Grotto 15's 20Hz:
Inputs and Outputs
- PreampLevel Inputs: Stereo RCA line, LFE, XLR, speaker level
- SpeakerLevel Inputs: Yes
MartinLogan Grotto 15 External Dimensions and Weight
MartinLogan Grotto 15 has external dimensions of (Height x Width x Depth) 20-9/16 x 21-13/16 x 21-13/16inch (522.0 x 554.0 x 554.0mm ).
Base Surface Area
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base area of MartinLogan Grotto 15 is approximately 3069.2cm2 / 475.7inch2.
Find speakers that fit your shelf or alcove →
WeightThe MartinLogan Grotto 15 weighs 53.50kg / 117.7lbs. Weight of a subwoofer is an important factor when you need to move and reposition the unit often to find the optimal positioning, also known as 'Subwoofer Crawling'. Here is a comparison of how Grotto 15's weight compares with the average, max and min weights in its class.
Weight
All Subwoofer Speakers
Weight
Subwoofer Speakers under $3000
Cabinet type and Materials
MartinLogan Grotto 15 has a
Acoustic Suspension type cabinet. Acoustic suspension aka Sealed subwoofers are preferred for music oriented systems whereas the Ported subwoofers are generally accepted to be more suitable for home theatre systems.
Does the MartinLogan Grotto 15 come with a Grille?
Grotto 15 comes with grilles. The purpose of the grille is to protect the delicate driver elements from external impacts while still allowing the sound to pass as clearly as possible.
Recommended Accessories
Here is a list of accessories that we think you may need for the MartinLogan Grotto 15.
Official Product Page
Official manufacturer's product page for the MartinLogan Grotto 15 speaker can be found below:
Official Product Page for MartinLogan Grotto 15
| General |
| Brand | MartinLogan |
| Full Model Name | MartinLogan Grotto 15 |
| Type | Powered Subwoofer |
| Release Date | 2026 |
| Frequency Response | 20-120 Hz |
| Enclosure Type | Sealed |
| Enclosure | Acoustic Suspension |
| Firing Direction | Front |
Amplifier & Driver |
| Power (RMS) | 1000 watts |
| Power (Peak) | 2000 watts |
| Amplifier Type | Class D |
| Woofer | 15-inch Aluminium |
| Passive Radiator | 2 x 15-inch |
| Controls & Connections |
| Phase Control | Yes |
| Line-level Inputs | Stereo RCA line, LFE, XLR, speaker level |
| Speaker-level Inputs | Yes |
Physical |
| Dimensions (HxWxD) | 20-9/16" x 21-13/16" x 21-13/16" (522.0 x 554.0 x 554.0mm) |
| Weight | 53.5 kg (118 lbs) |
| Grille | Yes |