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B&W CWM663 vs Definitive UIW RLS III Comparison

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B&W CWM663

Passive In-wall | 45-50kHz

Bowers & Wilkins Performance Series CWM663
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Definitive UIW RLS III

Passive In-wall | 24-30kHz

Definitive Technology UIW RLS III
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B&W CWM663 B&W CWM663
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Definitive UIW RLS III Definitive UIW RLS I...
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B&W CWM663 vs Definitive UIW RLS III Speaker Comparison

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

CWM663
UIW RLS III
Min
Average
Max
High Frequency

In-wall Speakers

B&W CWM663
Definitive UIW RLS III
Min
Average
Max

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

CWM663
UIW RLS III
Min
Average
Max

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 loudspeakers
  • 2 Mounting frames
  • 2 Grilles
  • 2 Paint mask
  • 2 Cut-out templates
  • Quick Start Guide
  • Template
  • Warranty Information
  • What's in the Box of Definitive UIW RLS III?

    Here are the items that come with the UIW RLS III:
  • In-wall loudspeaker
  • Grille
  • Self-adhesive foam gasket
  • Paint mask
  • Wall-Mount Template
  • Owners Manual
  • Online Product Registration Card

  • Reasons to choose Bowers & Wilkins Performance Series CWM663 over Definitive Technology UIW RLS III
    Woofer Size 6 inches vs 5.25 inches Larger woofer
    High Frequency Response 50k Hz vs 30k Hz Generates higher frequency
    Height 280mm vs 604mm Easier to fit in smaller spaces
    Price per pair* 900USD vs 1398USD costs less (*prices may change depending on the seller, location and time)

    Reasons to choose Definitive Technology UIW RLS III over Bowers & Wilkins Performance Series CWM663

    Max Input Power 325 watts vs 150 watts Handle more power from your amplifier
    Sensitivity 92 dB vs 88 dB Play louder with same amount of amplification power
    Number of Woofers 2 vs 1 More woofers
    Low Frequency Response 24 Hz vs 45 Hz Generates deeper bass
    Passive Radiator 2 x 5.25-inch vs None Increases the bass performance
    Base Surface Area 148cm2 vs 177cm2 Takes less floor space
    B&W CWM663 vs Definitive UIW RLS III Specs Table
    Detailed comparison of specifications
    General Bowers & Wilkins Performance Series CWM663 Definitive Technology UIW RLS III
    Brand Bowers Wilkins Definitive Technology
    Speaker Type Passive In-wall Speaker Passive In-wall Speaker
    Power Range 25-150 watts 10-325 watts
    Sensitivity 88 dB 92 dB
    Impedance 8 ohms 8 ohms
    Frequency Response 45-50kHz 24-30kHz
    Drivers
    Woofer Quantity 1 2
    Woofer Size 6" 5.25"
    Woofer Composition Kevlar Polypropylene
    Woofer Surround Material Rubber Butyl Rubber
    Tweeter Size 1" 1"
    Tweeter Type Soft-Dome Hard-Dome
    Aimable Tweeter No No
    Midrange Driver N/A" N/A"
    Physical Specs
    Height 280.0mm (11") 604.0mm (23.8")
    Width 185.0mm (7.3") 150.0mm (5.9")
    Depth 96.0mm (3.8") 99.0mm (3.9")
    Enclosure In-wall In-wall
    Moisture Resistancy No Yes
    Connections
    Biamp Inputs No No
    Other
    Parts Warranty 5 Years 5 Years
    Labor Warranty 5 Years 5 Years

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