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  1. Home
  2. Passive In-wall Speakers
  3. Monitor Audio CP-WT150 vs Definitive UIW RSS III

Monitor Audio CP-WT150 vs Definitive UIW RSS III Comparison

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Speaker to replace
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Monitor Audio CP-WT150

Passive In-wall | 75-25kHz

Monitor Audio CP-WT150
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Definitive UIW RSS III

Passive In-wall | 40-30kHz

Definitive Technology UIW RSS III
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Monitor Audio CP-WT150 Monitor Audio CP-WT1...
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Definitive UIW RSS III Definitive UIW RSS I...
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Monitor Audio CP-WT1...
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Definitive UIW RSS I...
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Monitor Audio CP-WT150 vs Definitive UIW RSS III Speaker Comparison

In this review, we will be comparing CP-WT150 and UIW RSS III, two Passive In-wall speakers from Monitor Audio and Definitive Technology.

Let's have a brief look at the main features of Monitor Audio CP-WT150 and Definitive UIW RSS III first before getting into our more detailed comparison.

Key SpecsMonitor Audio CP-WT150Definitive UIW RSS III
BrandMonitor Audio
United Kingdom · founded 1972
Definitive Technology
United States · founded 1990
Design2-way2-way
Tweeter1" Hard-Dome1" Hard-Dome
Woofer5" Poly2 x 3.5" Polypropylene
Frequency response75-25kHz40-30kHz
Sensitivity85 dB90 dB
Impedance6 ohms8 ohms
Power range20-50 watts10-200 watts
Weight—3.40kg / 7.5lbs
Dimensions (H x W x D)12.8125" x 8.1250" x 3.7500"
326.0 x 207.0 x 96.0mm
9.8750" x 8.3750" x 3.8750"
251.0 x 213.0 x 99.0mm

What size room are the Monitor Audio CP-WT150 and Definitive UIW RSS 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* Monitor Audio CP-WT150 Definitive UIW RSS III
Near-field Good Poor
Small Room Good Average
Mid-size Room Average Good
Large Room Poor Average
Very Large Room No way Poor

(* 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.)

The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.


Drivers

Both CP-WT150 and UIW RSS III are 2-way speakers.

Tweeter - 1 inchWoofer - 5 inch
Monitor Audio CP-WT150
Tweeter - 1 inchWoofer - 3.5 inchWoofer - 3.5 inch
Definitive UIW RSS III

TweeterWoofer

Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.

Driver Monitor Audio CP-WT150 Definitive UIW RSS III
Driver Setup 2-way 2-way
Tweeter 1-inch 1-inch
Midrange - -
Woofer 1 x 5-inch 2 x 3.5-inch

CP-WT150 features a 1" Hard-Dome Tweeter and 1 x 5" Poly Woofer. On the other hand, the UIW RSS III features a 1" Hard-Dome Tweeter and 2 x 3.5" Polypropylene Woofer.

Frequency Response

CP-WT150 has a frequency range of 75-25kHz whereas UIW RSS III has a frequency range of 40-30kHz. With a minimum frequency of 40Hz, the UIW RSS III can go significantly deeper on the low side and provide stronger bass compared to the CP-WT150's min frequency of 75Hz.

The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the In-wall class in our database.

Low Frequency

In-wall Speakers

CP-WT150
UIW RSS III
Min
Average
Median

Neither pair reaches down to 20Hz, the usual definition of full-range, which is normal for speakers of this size. If you want the bottom octave for movies or bass-heavy music, add a subwoofer to whichever you choose. Visit our Powered Subwoofers section to find out more about the available options.

Impedance and Sensitivity

CP-WT150 is a 6 ohms speaker compared to the UIW RSS III which has a nominal impedance of 8 ohms.

These two speakers also have different sensitivity levels. CP-WT150 sensitivity is rated at 85 dB and the UIW RSS III's is rated at 90 dB. This 5 dB difference makes the Definitive UIW RSS III a more sensitive speaker compared to Monitor Audio CP-WT150, hence will play louder with the same amount of watts.

Sensitivity

In-wall Speakers

CP-WT150
UIW RSS III
Min
Average
Median

Power Range

Power range is the range of input power in watts RMS that a loudspeaker is designed to handle. Staying within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.

UIW RSS III can handle a max power of 200 watts RMS, whereas CP-WT150 has a max power handling value of 50 watts RMS, 150 watts less than the UIW RSS III.

Note that higher power handling does not make a speaker louder: that depends mainly on sensitivity and impedance. The calculator below shows how loud each of these actually plays on a real amplifier.

Which plays louder on your amplifier?

Starting with a popular amplifier - change it to the one you own, or any you are considering, and watch both numbers move.

Monitor Audio CP-WT150
 
Definitive UIW RSS III
 

Input Type and Bi-Amping / Bi-Wiring

CP-WT150 features Spring post type posts and UIW RSS III 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 Monitor Audio CP-WT150's and Definitive UIW RSS III's external dimensions. Monitor Audio CP-WT150 has external dimensions of 326.0 x 207.0 x 96.0mm (12.8125-inch x 8.1250-inch x 3.7500-inch) whereas Definitive UIW RSS III has external dimensions of 251.0 x 213.0 x 99.0mm (9.8750-inch x 8.3750-inch x 3.8750-inch).

Monitor Audio CP-WT150 is 6mm narrower and 3mm less deeper than Definitive UIW RSS III but it is also 75mm taller.

What's in the Box of Monitor Audio CP-WT150?

Here are the items that are included inside the box of CP-WT150:
  • In-wall speaker
  • Magnetic grille
  • Cosmetic scrim
  • Installation Guide
  • Important Safety Instructions
  • Limited Warranty/Registration Card
  • MountingTemplate

What's in the Box of Definitive UIW RSS III?

Here are the items that come with the UIW RSS III:
  • In-wall/In-cieling bipolar speaker
  • Grille
  • 7 Foam strips
  • 2 Screws
  • Paint mask
  • Wall template
  • Owners Manual
  • Online Product Registration Card


Reasons to choose Monitor Audio CP-WT150 over Definitive Technology UIW RSS III

Woofer Size 5 inches vs 3.5 inches Larger woofer
Base Surface Area 198cm2 vs 210cm2 Takes less floor space
Price per pair* 880USD vs 1098USD costs less (*prices may change depending on the seller, location and time)

Reasons to choose Definitive Technology UIW RSS III over Monitor Audio CP-WT150

Max Input Power 200 watts vs 50 watts Handle more power from your amplifier
Sensitivity 90 dB vs 85 dB Play louder with same amount of amplification power
Nominal Impedance 8 ohms vs 6 ohms Less selective with amplifiers
Number of Woofers 2 vs 1 More woofers
Low Frequency Response 40 Hz vs 75 Hz Generates deeper bass
High Frequency Response 30k Hz vs 25k Hz Generates higher frequency
Passive Radiator 2 x 3.5-inch vs None Increases the bass performance
Height 251mm vs 326mm Easier to fit in smaller spaces

Monitor Audio CP-WT150 vs Definitive UIW RSS III Specs Table

Detailed comparison of specifications
General Monitor Audio CP-WT150 Definitive Technology UIW RSS III
Brand Monitor Audio Definitive Technology
Speaker Type Passive In-wall Speaker Passive In-wall Speaker
Power Range 20-50 watts 10-200 watts
Sensitivity 85 dB 90 dB
Impedance 6 ohms 8 ohms
Frequency Response 75-25kHz 40-30kHz
Drivers
Woofer Quantity 1 2
Woofer Size 5" 3.5"
Woofer Composition Poly Polypropylene
Woofer Surround Material Rubber Butyl Rubber
Tweeter Size 1" 1"
Tweeter Type Hard-Dome Hard-Dome
Aimable Tweeter No No
Midrange Driver No No
Physical Specs
Height 326.0mm (12.8") 251.0mm (9.9")
Width 207.0mm (8.1") 213.0mm (8.4")
Depth 96.0mm (3.8") 99.0mm (3.9")
Weight n/a 3.40kg (7.5lbs)
Enclosure In-wall In-wall
Moisture Resistancy No Yes
Connections
Biamp Inputs No No
Other
Parts Warranty Lifetime 5 Years
Labor Warranty Lifetime 5 Years

Verdict

No single best speaker here - they are built to different priorities, and the right one depends on your room, your amplifier and what you listen to.

AreaBetterWhy
BassBDefinitive UIW RSS III digs deeper - 40Hz against 75Hz.
Amplifier needsBDefinitive UIW RSS III is more sensitive (90dB vs 85dB), so it goes louder on the same amplifier.
Amplifier matchBDefinitive UIW RSS III is the easier load at 8 ohms.
HeadroomBDefinitive UIW RSS III takes more power (200W vs 50W) - more in hand in a big room.
SizedependsSimilar cabinet size - neither is easier to fit.
PriceAMonitor Audio CP-WT150 is cheaper - $880 against $1,098, about 20% less.

A Monitor Audio CP-WT150  B Definitive UIW RSS III
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 speakers are judged; anything missing on either side is left out rather than guessed.

Which should you choose?

Definitive UIW RSS III leads across most of the measured areas for a fairly modest premium, which makes it the easier pick if the budget stretches. Monitor Audio CP-WT150 is the one to take if it does not. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 75Hz anyway, which makes the cheaper Monitor Audio CP-WT150 much easier to justify. Match it to your room: we rate Monitor Audio CP-WT150 the better fit for near-field listening and a small room, and Definitive UIW RSS III for a mid-size room and a large room.

And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.


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