Short answer: the Miller & Kreisel IW150. It ranks #17 of 28 in-wall speakers by sound quality, rated 3.6/5, at $4,998; the Bowers & Wilkins CWM7.3 S2 ranks #22, rated 3.3/5, and costs $5,600, so there is little reason to consider the other one.
The Miller & Kreisel IW150 is the better-sounding pick. Erin’s Audio Corner’s Klippel measurement shows well controlled directivity (SPDI deviation 2.43dB) and a smooth predicted in-room response, with a preference score of 2.88, or 6.32 with a perfect subwoofer. The catch: Bass is thin: measured -3dB is 95.2Hz and -6dB is 82.0Hz, and Miller & Kreisel rates it only to 80Hz, so a subwoofer is required, and even with a perfect subwoofer the score reaches only 6.32.
The Bowers & Wilkins CWM7.3 S2 is the deeper-bass choice. A three-way in-wall speaker from B&W’s Reference series with two 6” Aerofoil bass drivers, a 4” Continuum midrange and a 1” Carbon Dome tweeter. Its bass reaches about 63Hz before falling 3dB, against 95.2Hz for the Miller & Kreisel IW150. Watch for: The on-axis response is uneven (1.66 average deviation) in Erin’s measurements.
Buy the Miller & Kreisel IW150. It is rated higher for sound quality than the Bowers & Wilkins CWM7.3 S2 and costs less, so only choose the other one for a particular feature it does better.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| Miller & Kreisel IW150 | Bowers & Wilkins CWM7.3 S2 | |
|---|---|---|
| Price | $4,998 per pair | $5,600 per pair |
| Ranked | #17 of 28 in In-Wall & In-Ceiling Speakers | #22 of 28 in In-Wall & In-Ceiling Speakers |
| Drivers | 2x 5.25” polypropylene bass/midrange drivers, 3x 1” soft fabric dome tweeters | 2x 6” Aerofoil bass drivers, 4” Continuum midrange, 1” Carbon Dome tweeter |
| Enclosure | In-wall | - |
| Mounting Cutout | 288W x 331H mm | - |
| Dimensions | 13.9”H x 12.2”W (354 x 311 mm) baffle (95mm mounting depth) | 29”H x 10.9”W x 4”D (736 x 276 x 102 mm) |
| Weight | 18.7 lbs (8.5 kg) | 27.3 lbs (12.4 kg) |
| Sensitivity | 90dB | 90dB (manufacturer specified) |
| Impedance | 4 ohms | 8 ohms nominal (manufacturer specified) |
| Power Handling | 25-400W recommended amplifier power | - |
| Frequency Response | 80Hz-20kHz +/-3dB (manufacturer) | - |
| Bass Extension (-3dB) | 95.2Hz (measured, Erin’s Audio Corner) | 63.0Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | 68.7Hz (measured, Erin’s Audio Corner) | about 43.4Hz (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 2.88 | 2.57 |
| Spinorama Preference Score with Perfect Sub | 6.32 | 5.36 |
| DIY Kit | No | No |
Frequency Response Compared
Both speakers’ spinorama measurements, overlaid. A flatter line is more neutral: peaks sound forward or harsh, dips sound recessed. Each curve is shifted so its average from 300 Hz to 3 kHz sits at 0 dB, so loudness differences between the two are removed and only the shape is compared.
Measurement data: Miller & Kreisel IW150 (measured by Erin’s Audio Corner) and Bowers & Wilkins CWM7.3 S2 (measured by Erin’s Audio Corner), via spinorama.org.
Related Speaker Comparisons
More worthwhile head-to-heads for Miller & Kreisel IW150:
- Revel W226Be vs Miller & Kreisel IW150
- JBL Synthesis SCL-6 vs Miller & Kreisel IW150
- JBL Synthesis SCL-3 vs Miller & Kreisel IW150
- JBL Synthesis SCL-7 vs Miller & Kreisel IW150
- JBL Synthesis SCL-4 vs Miller & Kreisel IW150
Prices on this page were last checked October 11, 2026 at 4:59 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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The Two Speakers In Full
Miller & Kreisel IW150: $4,998 per pair Audiolab (authorized M&K dealer) eBay
Pros: Erin’s Audio Corner’s Klippel measurement shows well controlled directivity (SPDI deviation 2.43dB) and a smooth predicted in-room response, with a preference score of 2.88, or 6.32 with a perfect subwoofer. The unusual layout puts two 5.25” polypropylene woofers beside a column of three 1” soft dome tweeters, a design meant to give even coverage across a room from a single wall opening. It is rated at 90dB sensitivity, and Erin’s measurement computed a real 88.2dB, and it accepts 25-400W of amplifier power. Measured bass extension of 95.2Hz (-3dB).
Cons: Bass is thin: measured -3dB is 95.2Hz and -6dB is 82.0Hz, and Miller & Kreisel rates it only to 80Hz, so a subwoofer is required, and even with a perfect subwoofer the score reaches only 6.32. On-axis smoothness is 0.48 and on-axis deviation averages 0.62dB, so the midrange is rougher than the better in-wall designs. At $2499 each a stereo pair costs twice that. Erin describes it as discontinued from what he can tell, so stock may be limited to remaining inventory.
Full Miller & Kreisel IW150 review and specifications →
| Bass Extension (-10dB) | 68.7Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 95.2Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 13.9”H x 12.2”W (354 x 311 mm) baffle (95mm mounting depth) |
| Drivers | 2x 5.25” polypropylene bass/midrange drivers, 3x 1” soft fabric dome tweeters |
| Enclosure | In-wall |
| Frequency Response | 80Hz-20kHz +/-3dB (manufacturer) |
| Impedance | 4 ohms |
| Mounting Cutout | 288W x 331H mm |
| Power Handling | 25-400W recommended amplifier power |
| Sensitivity | 90dB |
| Spinorama Preference Score | 2.88 |
| Spinorama Preference Score with Perfect Sub | 6.32 |
| Weight | 18.7 lbs (8.5 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Miller & Kreisel IW150 vs JBL Synthesis SCL-4
- Miller & Kreisel IW150 vs Revel W990
- Miller & Kreisel IW150 vs JBL Synthesis SCL-7
- Miller & Kreisel IW150 vs JBL Synthesis SCL-3
- Miller & Kreisel IW150 vs Focal 1000 IWLCR6
- Miller & Kreisel IW150 vs MartinLogan Tribute 5XW
- Miller & Kreisel IW150 vs JBL Synthesis SCL-6
- Miller & Kreisel IW150 vs Revel W226Be
Bowers & Wilkins CWM7.3 S2: $5,600 per pair B&H Photo Video eBay
Same family: the Bowers & Wilkins CWM 7.5 S2 (smaller in-wall, ranked lower, estimated 3/5). See every Bowers & Wilkins CWM In-Wall generation.
Pros: A three-way in-wall speaker from B&W’s Reference series with two 6” Aerofoil bass drivers, a 4” Continuum midrange and a 1” Carbon Dome tweeter. Erin measured a preference score of 2.57 that reaches 5.36 with an ideal subwoofer, with 0.59 listening window deviation. Measured bass extension of 63.0Hz (-3dB).
Cons: The on-axis response is uneven (1.66 average deviation) in Erin’s measurements. Bass reaches 63.0Hz (-3dB) and about 43Hz (-10dB).
Full Bowers & Wilkins CWM7.3 S2 review and specifications →
| Released | 2019 (7 years ago) |
|---|---|
| Bass Extension (-10dB) | about 43.4Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 63.0Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 29”H x 10.9”W x 4”D (736 x 276 x 102 mm) |
| Drivers | 2x 6” Aerofoil bass drivers, 4” Continuum midrange, 1” Carbon Dome tweeter |
| Impedance | 8 ohms nominal (manufacturer specified) |
| Sensitivity | 90dB (manufacturer specified) |
| Spinorama Preference Score | 2.57 |
| Spinorama Preference Score with Perfect Sub | 5.36 |
| Weight | 27.3 lbs (12.4 kg) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons