Short answer: the JBL Synthesis SCL-7. It ranks #11 of 18 in-wall speakers by sound quality, rated 3.7/5, at $2,419.90; the Miller & Kreisel IW150 ranks #13, rated 3.6/5, and costs $4,998, so there is little reason to consider the other one.
Why pick the JBL Synthesis SCL-7: Audio Science Review measured a 1.88 directivity-index deviation, among the most consistent off-axis behavior of the JBL Synthesis in-walls, and 0.60 listening-window smoothness. Watch for: The response sits in a wide 4.1dB reference band with 0.43dB average on-axis deviation, so tonal balance is less even than the SCL-6.
Why pick the Miller & Kreisel IW150: 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 tradeoff: 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.
Buy the JBL Synthesis SCL-7. It is rated higher for sound quality than the Miller & Kreisel IW150 and costs less, so it is the default pick unless a specific strength of the other one matters more to you.
Looking for alternatives? See the complete Passive Home rankings.
Specifications Side By Side
| JBL Synthesis SCL-7 | Miller & Kreisel IW150 | |
|---|---|---|
| Price | $2,419.90 per pair | $4,998 per pair |
| Ranked | #11 of 18 in In-Wall & In-Ceiling Speakers | #13 of 18 in In-Wall & In-Ceiling Speakers |
| Drivers | Two 5.25” aluminum matrix cone woofers, 1” 2410H-2 compression driver on HDI horn (2-way) | 2x 5.25” polypropylene bass/midrange drivers, 3x 1” soft fabric dome tweeters |
| Enclosure | In-wall, open back | In-wall |
| Mounting Cutout | 157 x 458mm (6.18 x 18.03 in) | 288W x 331H mm |
| Dimensions | 19.1”H x 7.3”W x 3.9”D (486 x 186 x 99 mm) (93mm mounting depth) | 13.9”H x 12.2”W (354 x 311 mm) baffle (95mm mounting depth) |
| Weight | 12.6 lbs (5.72 kg) | 18.7 lbs (8.5 kg) |
| Sensitivity | 88dB (2.83V/1m, 2pi anechoic) | 90dB |
| Impedance | 4 ohms | 4 ohms |
| Power Handling | 25-150W recommended amplifier power | 25-400W recommended amplifier power |
| Frequency Response | 55Hz-30kHz -6dB (manufacturer, 2pi) | 80Hz-20kHz +/-3dB (manufacturer) |
| Crossover Frequency | 2.0kHz | - |
| Bass Extension (-3dB) | 67.4Hz (measured, spinorama.org ASR data) | 95.2Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | 42.3Hz (measured, spinorama.org ASR data) | 68.7Hz (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 3.46 | 2.88 |
| Spinorama Preference Score with Perfect Sub | 6.21 | 6.32 |
| DIY Kit | No | No |
Related Speaker Comparisons
More worthwhile head-to-heads for JBL Synthesis SCL-7:
- Monolith THX-365IW vs JBL Synthesis SCL-7
- JBL Synthesis SCL-6 vs JBL Synthesis SCL-7
- JBL Synthesis SCL-7 vs KEF CI200RR-THX
- JBL Synthesis SCL-7 vs JBL Synthesis SCL-3
- JBL Synthesis SCL-7 vs Revel W990
Prices on this page were last checked September 26, 2026 at 11:14 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
JBL Synthesis SCL-7: $2,419.90 per pair Audio Advice eBay
Pros: Audio Science Review measured a 1.88 directivity-index deviation, among the most consistent off-axis behavior of the JBL Synthesis in-walls, and 0.60 listening-window smoothness. The preference score rises from 3.46 to 6.21 with a subwoofer. Two 5.25-inch aluminum woofers and a 2410H-2 compression driver on JBL’s imaging horn give bass to 67.4Hz at -3dB and about 42.3Hz at -10dB in free air, and at $1210 each it is the least expensive way into the JBL Synthesis in-wall range. Measured bass extension of 67.4Hz (-3dB).
Cons: The response sits in a wide 4.1dB reference band with 0.43dB average on-axis deviation, so tonal balance is less even than the SCL-6. The 3.46 standard score is low without a subwoofer. At 88dB it is 3dB less sensitive than its siblings, and the 4 ohm load needs a capable amplifier.
Full JBL Synthesis SCL-7 review and specifications →
| Bass Extension (-10dB) | 42.3Hz (measured, spinorama.org ASR data) |
|---|---|
| Bass Extension (-3dB) | 67.4Hz (measured, spinorama.org ASR data) |
| Crossover Frequency | 2.0kHz |
| DIY Kit | No |
| Dimensions | 19.1”H x 7.3”W x 3.9”D (486 x 186 x 99 mm) (93mm mounting depth) |
| Drivers | Two 5.25” aluminum matrix cone woofers, 1” 2410H-2 compression driver on HDI horn (2-way) |
| Enclosure | In-wall, open back |
| Frequency Response | 55Hz-30kHz -6dB (manufacturer, 2pi) |
| Impedance | 4 ohms |
| Mounting Cutout | 157 x 458mm (6.18 x 18.03 in) |
| Power Handling | 25-150W recommended amplifier power |
| Sensitivity | 88dB (2.83V/1m, 2pi anechoic) |
| Spinorama Preference Score | 3.46 |
| Spinorama Preference Score with Perfect Sub | 6.21 |
| Weight | 12.6 lbs (5.72 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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