In this review, we will be comparing IW Sub Reference and B28W, two Passive In-wall speakers from Definitive Technology and Revel. Let's have a brief look at the main features of Definitive IW Sub Reference and Revel B28W 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.
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Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.Definitive IW Sub Reference and Revel B28W have a totally different setup: the Definitive IW Sub Reference features 1 x 13-inch drivers whereas the B28W features 2 x 8-inch drivers.
Frequency Response
IW Sub Reference has a frequency range of 14-200Hz whereas B28W has a frequency range of 36-150Hz. 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 B28W's min frequency of 36Hz.
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
IW Sub Reference has a power range of up to 275 watts RMS whereas B28W has a power range of 350 watts.
Input Type and Bi-Amping / Bi-Wiring
IW Sub Reference features Spring post type posts and B28W has a Spring post type posts. None of these speakers feature bi-amping/bi-wiring.
Cabinet Type
Both Definitive IW Sub Reference and Revel B28W have In-wall type cabinets.
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 Definitive IW Sub Reference's and Revel B28W's external dimensions. 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) whereas Revel B28W has external dimensions of 597.0 x 369.0 x 102.0mm (23.5000-inch x 14.5000-inch x 4.0000-inch).
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 Definitive IW Sub Reference weighs 11.79kg / 25.9lbs and the Revel B28W weighs 12.88kg / 28.3lbs. This makes the B28W 9% heavier than the IW Sub Reference.
Here is a comparison of how IW Sub Reference and B28W'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 Definitive IW Sub Reference?
Here are the items that are included inside the box of 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
What's in the Box of Revel B28W?
Here are the items that come with the B28W:
- In-wall subwoofer
- Grille
- 8 Screws
- 8 Washers
- 8 Isolators
- Owners Manual
 Woofer Size |
13 inches
vs
8 inches
|
Larger woofer |
| Low Frequency Response |
14 Hz
vs
36 Hz
|
Generates deeper bass |
 High Frequency Response |
200 Hz
vs
150 Hz
|
Generates higher frequency |
 Passive Radiator |
1 x 13-inch
vs
None
|
Increases the bass performance |
 Base Surface Area |
373cm2
vs
376cm2
|
Takes less floor space |
 Max Input Power |
350 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 |
 Price per pair* |
1100USD
vs
1499USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Definitive Technology IW Sub Reference |
Revel B28W |
| Brand |
Definitive Technology |
Revel |
| Speaker Type |
Passive Subwoofer |
Passive Subwoofer |
| Power Range |
up to 275 watts |
350 watts |
| Impedance |
4 ohms |
8 ohms |
| Frequency Response |
14-200Hz |
36-150Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
2 |
| Woofer Size |
13" |
8" |
| Woofer Composition |
|
Polymer-coated aluminum |
| Woofer Surround Material |
n/a |
Rubber |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
Physical Specs |
|
|
| Height |
597.0mm (23.5") |
597.0mm (23.5") |
| Width |
366.0mm (14.4") |
369.0mm (14.5") |
| Depth |
102.0mm (4") |
102.0mm (4") |
| Weight |
11.79kg (25.9lbs) |
12.88kg (28.3lbs) |
| Enclosure |
In-wall |
In-wall |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
Lifetime |
| Labor Warranty |
5 Years |
Lifetime |
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 | A | Definitive IW Sub Reference goes deeper - 14Hz against 36Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Driver area | A | 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. |
| Enclosure | evenly matched | Both are in-wall designs, so they roll off in much the same way. |
| Warranty | B | Revel B28W carries a lifetime warranty on parts against 5 years. A subwoofer amplifier works harder than anything else in the system, so this is not a throwaway line. |
| Price | B | Revel B28W costs less - $1,100 against $1,499, about 27% less. |
A Definitive IW Sub Reference B Revel B28W
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?
Definitive IW Sub Reference is ahead, but on only 1 of the measured areas, and it costs about 36% more. Revel B28W is the sensible buy unless your room is large enough to need the extra.
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.