B&W CWM7.3 S2 vs B&W CWM664 Comparison

Speaker to replace

Change

B&W CWM7.3 S2

Passive In-wall | 48-28kHz

Check price atAmazon›

Change

B&W CWM664

Passive In-wall | 45-35kHz

Check price atAmazon›

B&W CWM7.3 S2

Check price atAmazon›

B&W CWM664

Check price atAmazon›

B&W CWM7.3 S2

See at AMAZON

B&W CWM664

See at AMAZON

B&W CWM7.3 S2 vs B&W CWM664 Speaker Comparison

In this review, we will be comparing CWM7.3 S2 and CWM664, two Passive In-wall speakers by Bowers Wilkins.

Let's have a brief look at the main features of B&W CWM7.3 S2 and B&W CWM664 first before getting into our more detailed comparison.

Key Specs	B&W CWM7.3 S2	B&W CWM664
Brand	Bowers Wilkins United Kingdom · founded 1966	Bowers Wilkins United Kingdom · founded 1966
Design	3-way	2-way
Tweeter	1" Soft-Dome	1" Soft-Dome
Midrange	4"	—
Woofer	2 x 6" Aerofoil	6" Glass-fiber
Frequency response	48-28kHz	45-35kHz
Sensitivity	90 dB	87.5 dB
Impedance	8 ohms	8 ohms
Power range	25-200 watts	25-130 watts
Weight	12.43kg / 27.3lbs	—
Dimensions (H x W x D)	28.0000" x 9.9375" x 4.0625" 712.0 x 253.0 x 104.0mm	11.0000" x 7.2500" x 3.7500" 280.0 x 185.0 x 96.0mm

What size room are the B&W CWM7.3 S2 and B&W CWM664 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 CWM7.3 S2	B&W CWM664
Near-field	Poor	Poor
Small Room	Average	Average
Mid-size Room	Good	Good
Large Room	Average	Average
Very Large Room	Poor	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

One of the fundamental differences between these two speakers is that CWM7.3 S2 is a 3-way design whereas the CWM664 is a 2-way speaker. 3-way designs utilize a midrange driver in addition to the tweeter and woofer on 2-way designs. Designing a crossover for a 3-way speaker is a complicated process and generally increases the overall cost of the speaker.

B&W CWM7.3 S2

B&W CWM664

TweeterMidrangeWoofer

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

Driver	B&W CWM7.3 S2	B&W CWM664
Driver Setup	3-way	2-way
Tweeter	1-inch	1-inch
Midrange	1 x 4-inch	-
Woofer	2 x 6-inch	1 x 6-inch

CWM7.3 S2 features a 1" Soft-Dome Tweeter, a 4" Midrange and 2 x 6" Aerofoil Woofer. On the other hand, the CWM664 features a 1" Soft-Dome Tweeter and 1 x 6" Glass-fiber Woofer.

Frequency Response

CWM7.3 S2 has a frequency range of 48-28kHz whereas CWM664 has a frequency range of 45-35kHz. With a minimum frequency of 45Hz, the CWM664 can go slightly deeper then the CWM7.3 S2's min frequency of 48Hz.

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

CWM7.3 S2

CWM664

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

CWM7.3 S2 and CWM664 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. CWM7.3 S2 sensitivity is rated at 90 dB and the CWM664's is at 87.5 dB. This 2 dB difference makes the B&W CWM7.3 S2 a more sensitive speaker compared to B&W CWM664, hence will play louder with the same amount of watts.

Sensitivity

In-wall Speakers

CWM7.3 S2

CWM664

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.

CWM7.3 S2 can handle a max power of 200 watts RMS, whereas CWM664 has a max power handling value of 130 watts RMS, 70 watts less than the CWM7.3 S2.

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.

Amplifier - change this

Distance

Playing as

B&W CWM7.3 S2

B&W CWM664

Input Type and Bi-Amping / Bi-Wiring

CWM7.3 S2 features Spring post type posts and CWM664 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 B&W CWM7.3 S2's and B&W CWM664's external dimensions. B&W CWM7.3 S2 has external dimensions of 712.0 x 253.0 x 104.0mm (28.0000-inch x 9.9375-inch x 4.0625-inch) whereas B&W CWM664 has external dimensions of 280.0 x 185.0 x 96.0mm (11.0000-inch x 7.2500-inch x 3.7500-inch).

B&W CWM7.3 S2 is clearly the larger of the two speakers. Its body is 68mm wider, 432mm taller and 8mm deeper than B&W CWM664.

What's in the Box of B&W CWM7.3 S2?

Here are the items that are included inside the box of CWM7.3 S2:

In-wall loudspeaker
Mounting frame
Grille
Baffle box
2 Mounting plates (1 pre-installed)
Paint shield
Two-piece foam port plug
8 Screws
2 Wing-nuts
Hex-wrench
Cutout Template
Installation Instructions
Warranty Information

What's in the Box of B&W CWM664?

Here are the items that come with the CWM664:

2 In-wall loudspeakers
2 Mounting frames
2 Grilles
2 Paint mask
2 Cut-out templates
Quick Start Guide
Template
Warranty Information

Reasons to choose Bowers & Wilkins Reference Series CWM7.3 S2 over Bowers & Wilkins Performance Series CWM664

Max Input Power	200 watts vs 130 watts	Handle more power from your amplifier
Driver Setup	3-way vs 2-way	Have a dedicated mid-range driver
Sensitivity	90 dB vs 88 dB	Play louder with same amount of amplification power
Number of Woofers	2 vs 1	More woofers

Reasons to choose Bowers & Wilkins Performance Series CWM664 over Bowers & Wilkins Reference Series CWM7.3 S2

Low Frequency Response	45 Hz vs 48 Hz	Generates deeper bass
High Frequency Response	35k Hz vs 28k Hz	Generates higher frequency
Height	280mm vs 712mm	Easier to fit in smaller spaces
Base Surface Area	177cm² vs 263cm²	Takes less floor space
Price per pair*	700USD vs 4200USD	costs less (*prices may change depending on the seller, location and time)

B&W CWM7.3 S2 vs B&W CWM664 Specs Table

Detailed comparison of specifications

General	Bowers & Wilkins Reference Series CWM7.3 S2	Bowers & Wilkins Performance Series CWM664
Brand	Bowers Wilkins	Bowers Wilkins
Speaker Type	Passive In-wall Speaker	Passive In-wall Speaker
Power Range	25-200 watts	25-130 watts
Sensitivity	90 dB	87.5 dB
Impedance	8 ohms	8 ohms
Frequency Response	48-28kHz	45-35kHz
Drivers
Woofer Quantity	2	1
Woofer Size	6"	6"
Woofer Composition	Aerofoil	Glass-fiber
Woofer Surround Material	Rubber	Rubber
Tweeter Size	1"	1"
Tweeter Type	Soft-Dome	Soft-Dome
Aimable Tweeter	No	No
Midrange Driver	4"	No
Physical Specs
Height	712.0mm (28")	280.0mm (11")
Width	253.0mm (10")	185.0mm (7.3")
Depth	104.0mm (4.1")	96.0mm (3.8")
Weight	12.43kg (27.3lbs)	n/a
Enclosure	In-wall	In-wall
Moisture Resistancy	No	No
Connections
Biamp Inputs	No	No
Other
Parts Warranty	5 Years	5 Years
Labor Warranty	5 Years	5 Years

Verdict

These sit in different price classes - B&W CWM7.3 S2 costs roughly 6x what B&W CWM664 does. Expect it to lead on paper; the question is whether the gap is audible enough in your room to be worth it.

Area	Better	Why
Bass	B	B&W CWM664 digs deeper - 45Hz against 48Hz. A subwoofer would even that out.
Amplifier needs	A	B&W CWM7.3 S2 is more sensitive (90dB vs 88dB), so it goes louder on the same amplifier.
Headroom	A	B&W CWM7.3 S2 takes more power (200W vs 130W) - more in hand in a big room.
Size	depends	B&W CWM664 is easier to place; B&W CWM7.3 S2 is bigger, which usually goes with fuller bass. Your room decides.
Price	B	B&W CWM664 is cheaper - $700 against $4,200, about 83% less; arguably a different class.

A B&W CWM7.3 S2 B B&W CWM664
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?

B&W CWM7.3 S2 is ahead, but only on 1 of the measured areas, and it costs about 6x the price. That is a lot of money for a narrow margin on paper - B&W CWM664 looks like the sensible buy unless something else about the B&W CWM7.3 S2 appeals to you. In a large or open-plan room, B&W CWM7.3 S2 has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, B&W CWM664 is the easier speaker to get right. If your amplifier is modest, vintage or valve-based, B&W CWM7.3 S2 is the safer partner - the other will want more current or more watts to sound its best.

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.