In this review, we will be comparing Dynamo IW-O and IW Sub Reference, two Passive In-wall speakers from MartinLogan and Definitive Technology. Let's have a brief look at the main features of MartinLogan Dynamo IW-O and Definitive IW Sub Reference 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.MartinLogan Dynamo IW-O and Definitive IW Sub Reference have a totally different setup: the MartinLogan Dynamo IW-O features 2 x 8-inch drivers whereas the IW Sub Reference features 1 x 13-inch drivers.
Frequency Response
Dynamo IW-O has a frequency range of 30-190Hz whereas IW Sub Reference has a frequency range of 14-200Hz. With a minimum frequency of 14Hz, the IW Sub Reference can go significantly deeper on the low side and provide stronger bass compared to the Dynamo IW-O'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 In-wall class in our database.
Low Frequency
In-wall Speakers
Definitive IW Sub Reference
High Frequency
In-wall Speakers
Definitive IW Sub Reference
Power Range
Dynamo IW-O has a power range of 50-400 watts RMS whereas IW Sub Reference has a power range of up to 275 watts.
Input Type and Bi-Amping / Bi-Wiring
Dynamo IW-O features Spring post type posts and IW Sub Reference has a Spring post type posts. None of these speakers feature bi-amping/bi-wiring.
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 Dynamo IW-O's and Definitive IW Sub Reference's external dimensions. MartinLogan Dynamo IW-O has external dimensions of 485.4 x 272.5 x 104.1mm () whereas Definitive IW Sub Reference has external dimensions of 639.0 x 366.0 x 102.0mm (25.1250-inch x 14.3750-inch x 4.0000-inch).
MartinLogan Dynamo IW-O is 93.5mm narrower and 153.6mm shorter than Definitive IW Sub Reference but it is also 2.1mm deeper.
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 Dynamo IW-O weighs 6.80kg / 15lbs and the Definitive IW Sub Reference weighs 11.79kg / 25.9lbs. This makes the IW Sub Reference 73% heavier than the Dynamo IW-O.
Here is a comparison of how Dynamo IW-O and IW Sub Reference's weights compare with the average, max and min weights in Passive In-wall class.
Weight
All In-wall Speakers
Definitive IW Sub Reference
What's in the Box of MartinLogan Dynamo IW-O?
Here are the items that are included inside the box of Dynamo IW-O:
- In-wall subwoofer
- Grille
- Cutout Template
What's in the Box of Definitive IW Sub Reference?
Here are the items that come with the IW Sub Reference:
- In-wall subwoofer
- Grille (attached)
- 4 Long self-adhesive foam gaskets
- 3 Short self-adhesive foam gaskets
- 8 Screws
- Wall-template
- Paint mask
- Owners Manual
- Online Product Registration card
 Max Input Power |
400 watts
vs
275 watts
|
Handle more power from your amplifier |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
 Number of Woofers |
2
vs
1
|
More woofers |
 Height |
485mm
vs
639mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
283cm2
vs
373cm2
|
Takes less floor space |
 Price per pair* |
1398USD
vs
1499USD
|
costs less (*prices may change depending on the seller, location and time) |
| Woofer Size |
13 inches
vs
8 inches
|
Larger woofer |
| Low Frequency Response |
14 Hz
vs
30 Hz
|
Generates deeper bass |
 High Frequency Response |
200 Hz
vs
190 Hz
|
Generates higher frequency |
 Passive Radiator |
1 x 13-inch
vs
None
|
Increases the bass performance |
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.
Definitive IW Sub Reference needs about 32% more floor area. Definitive IW Sub Reference is 154mm taller.
| General |
MartinLogan Dynamo IW-O |
Definitive Technology IW Sub Reference |
| Brand |
MartinLogan |
Definitive Technology |
| Speaker Type |
Passive Subwoofer |
Passive Subwoofer |
| Power Range |
50-400 watts |
up to 275 watts |
| Impedance |
8 ohms |
4 ohms |
| Frequency Response |
30-190Hz |
14-200Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
1 |
| Woofer Size |
8" |
13" |
| Woofer Composition |
|
|
| Woofer Surround Material |
Thermal Plastic Rubber (TPR) |
n/a |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
Physical Specs |
|
|
| Height |
485.4mm (19.1") |
639.0mm (25.2") |
| Width |
272.5mm (10.7") |
366.0mm (14.4") |
| Depth |
104.1mm (4.1") |
102.0mm (4") |
| Weight |
6.80kg (15lbs) |
11.79kg (25.9lbs) |
| Enclosure |
|
In-wall |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 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 | Definitive IW Sub Reference goes deeper - 14Hz against 30Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Driver area | B | Definitive IW Sub Reference moves more air: 13" against 2 x 8" is 1.32x the cone area, not the 1.15x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Cabinet size | depends | MartinLogan Dynamo IW-O is about 42% 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 | A | MartinLogan Dynamo IW-O costs less - $1,398 against $1,499, about 7% less. |
A MartinLogan Dynamo IW-O B Definitive IW Sub Reference
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: Definitive IW Sub Reference measures better, MartinLogan Dynamo IW-O costs about 7% less. In a normal room, placement will make a bigger difference than the gap between these two. If placement is the constraint - a corner, behind a sofa, under a desk - MartinLogan Dynamo IW-O 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.