Short answer: the JBL Synthesis SCL-6. It ranks #10 of 28 in-wall speakers by sound quality, rated 3.9/5, at $3,629.90; the Miller & Kreisel IW150 ranks #17, rated 3.6/5, and costs $4,998, which makes this an easy call rather than a real tradeoff.
The JBL Synthesis SCL-6 is the more accurate, deeper-bass choice. A high output in-wall speaker with four woofers and a horn tweeter, giving very even, accurate sound across the room. Its measured preference score, a predictor of how neutral it sounds, is 3.92 against 2.88 for the Miller & Kreisel IW150. Its bass reaches about 67.4Hz before falling 3dB, against 95.2Hz for the Miller & Kreisel IW150. The catch: Bass is limited without a subwoofer, and a 3.92 standard score trails the best in-wall speakers here.
Why pick the Miller & Kreisel IW150: An in-wall speaker with three tweeters beside two woofers, designed to spread sound evenly across a room from one opening. Watch for: 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-6. It is rated higher for sound quality than the Miller & Kreisel IW150 and costs less, which makes it the one to get unless you need something the other one does better.
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Specifications Side By Side
| JBL Synthesis SCL-6 | Miller & Kreisel IW150 | |
|---|---|---|
| Price | $3,629.90 per pair | $4,998 per pair |
| Ranked | #10 of 28 in In-Wall & In-Ceiling Speakers | #17 of 28 in In-Wall & In-Ceiling Speakers |
| Drivers | Four 5.25” aluminum matrix cone woofers, 1” 2410H-2 compression driver on HDI horn (2.5-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 766mm (6.18 x 30.18 in) | 288W x 331H mm |
| Dimensions | 31.3”H x 7.3”W x 3.8”D (796 x 185 x 97 mm) (92mm mounting depth) | 13.9”H x 12.2”W (354 x 311 mm) baffle (95mm mounting depth) |
| Weight | 22.2 lbs (10.07 kg) | 18.7 lbs (8.5 kg) |
| Sensitivity | 91dB (2.83V/1m, 2pi anechoic) | 90dB |
| Impedance | 4 ohms | 4 ohms |
| Power Handling | 25-200W recommended amplifier power | 25-400W recommended amplifier power |
| Frequency Response | 50Hz-30kHz -6dB (manufacturer, 2pi) | 80Hz-20kHz +/-3dB (manufacturer) |
| Crossover Frequency | 1.8kHz | - |
| Bass Extension (-3dB) | 67.4Hz (measured, spinorama.org Erin’s Audio Corner data) | 95.2Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | 40.8Hz (measured, spinorama.org Erin’s Audio Corner data) | 68.7Hz (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 3.92 | 2.88 |
| Spinorama Preference Score with Perfect Sub | 6.71 | 6.32 |
| DIY Kit | No | No |
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