In this review, we will be comparing CWM663 and UIW RLS III, two Passive In-wall speakers from Bowers Wilkins and Definitive Technology. Let's have a brief look at the main features
of B&W CWM663 and Definitive UIW RLS III first before getting into our more
detailed comparison.
B&W CWM663 Key Specs
- 2-way Design
- 1" Soft-Dome Tweeter
- 6" Kevlar Woofer
- 45-50kHz Frequency Response
- 88 dB Sensitivity
- Impedance: 8ohms
- Power Range:25-150watts
- Dimensions (H x W x D): 280.0" x 7.2500" x 3.7500"( 280.0 x 185.0 x 96.0mm )
Definitive UIW RLS III Key Specs
- 2-way Design
- 1" Hard-Dome Tweeter
- 2 x 5.25" Polypropylene Woofer
- 24-30kHz Frequency Response
- 92 dB Sensitivity
- Impedance: 8ohms
- Power Range:10-325watts
- Dimensions (H x W x D): 604.0" x 5.8750" x 3.8750"( 604.0 x 150.0 x 99.0mm )
What size room are the B&W CWM663 and Definitive UIW RLS III speakers good for?
The size of the room in which you are planning to use these loudspeakers is an important decision factor. Here we have compared their suitability to various sizes of environments considering their size and max power parameters:
| Listening Environment* |
B&W CWM663 |
Definitive UIW RLS III |
| Near-field |
Poor |
Are you nuts? |
| Small Room |
Average |
Bad |
| Mid-size Room |
Good |
Poor |
| Large Room |
Average |
Good |
| Very Large Room |
Poor |
Good |
(* Approximate Room sizes: Small < 100sq. ft / 9 m2, Mid-size: 100-220 sq. ft / 9-20 m2, Large 220-400 sq. ft / 20-36 m2, Very Large: > 400 sq. ft / 36 m2.
Average Floor Height: 9" / 2.7m. Typical room sizes differ from country to country, and the actual listening experience changes depending on floor height, room shape, surface materials, listening position, speaker locations, etc.)
In the following sections, we will get into more detail in order to better understand how the B&W CWM663 and Definitive UIW RLS III compare and hopefully end up with enough arguments to decide which one of these loudspeakers 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
Both CWM663 and UIW RLS III are 2-way speakers.
| Driver |
B&W CWM663 |
Definitive UIW RLS III |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 6-inch
|
2 x 5.25-inch
|
CWM663 features a 1" Soft-Dome Tweeter and 1 x 6" Kevlar Woofer . On the other hand, the UIW RLS III features a 1" Hard-Dome Tweeter and 2 x 5.25" Polypropylene Woofer .
Frequency Response
CWM663 has a frequency range of 45-50kHz whereas UIW RLS III has a frequency range of 24-30kHz. With a minimum frequency of 24Hz, the UIW RLS III can go significantly deeper on the low side and provide stronger bass compared to the CWM663's min frequency of 45Hz.
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
High Frequency
In-wall Speakers
None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
CWM663 and UIW RLS III have the same Impedance of 8 ohms but where they differ is the sensitivity levels. CWM663 sensitivity is rated at 88 dB and the UIW RLS III's is at 92 dB. This 4 dB difference makes the Definitive UIW RLS III a more sensitive speaker compared to B&W CWM663, hence will play louder with the same amount of watts.
Sensitivity
In-wall Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. While using an amplifier within this range ensures the nominal performance , inputting a power that is higher than the max wattage can result in a damaged speaker.
CWM663 can handle a max power of 325 watts RMS from the amp the whereas CWM663 has a max power handling value of 150 watts RMS , 175 watts less than the UIW RLS III.
Keep in mind that a higher max power handling value doesn't necessarily make that a louder speaker
compared to a lower max handling speaker. Loudness or the sound level is also impacted by parameters
such as Impedance, sensitivity and system efficiencies.
Input Type and Bi-Amping / Bi-Wiring
CWM663 features Spring post type posts and UIW RLS III has a Spring post type posts. None of these speakers feature bi-amping/bi-wiring.
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 B&W CWM663's and Definitive UIW RLS III's external dimensions. B&W CWM663 has external dimensions of 280.0 x 185.0 x 96.0mm ( 11.0000-inch x 7.2500-inch x 3.7500-inch) whereas Definitive UIW RLS III has external dimensions of 604.0 x 150.0 x 99.0mm ( 23.7500-inch x 5.8750-inch x 3.8750-inch) .
B&W CWM663 is 324mm shorter and 3mm less deeper than Definitive UIW RLS III but it is also 35mm wider.
What's in the Box of B&W CWM663?
Here are the items that are included inside the box of CWM663:
2 In-wall loudspeakers2 Mounting frames2 Grilles2 Paint mask2 Cut-out templatesQuick Start GuideTemplateWarranty Information
What's in the Box of Definitive UIW RLS III?
Here are the items that come with the UIW RLS III:
In-wall loudspeakerGrilleSelf-adhesive foam gasketPaint maskWall-Mount TemplateOwners ManualOnline Product Registration Card
Woofer Size 
High Frequency Response 
Height 
Price per pair* 
Max Input Power 
Sensitivity 
Passive Radiator 
Base Surface Area