Short answer: both are discontinued, so this only matters if you are buying used. Used, the MartinLogan Dynamo 1600X is the better pick: it ranks #3 of 212 subwoofers by sound quality (rated 4.2/5), against #206 (rated 2.9/5) for the JBL SUB 550P.
The MartinLogan Dynamo 1600X is the better-sounding choice. A sealed 15 inch subwoofer with forceful, tight bass, front or down firing setup, and app based room correction, now discontinued. The tradeoff: Output falls to 86.2dB at 15Hz, so the very lowest effects are weaker than the strong midbass numbers suggest.
What the JBL SUB 550P does well: A discontinued sealed 10 inch subwoofer with a 300 watt amp, multiple line inputs and an adjustable crossover. The tradeoff: Bass is strong to about 30Hz but 10dB down there against the 60 to 80Hz range.
Buy the MartinLogan Dynamo 1600X only if you find one used in good condition; both are discontinued, and it is the better rated of the two.
Want more options? Browse the full Subwoofers rankings.
A sealed 15 inch subwoofer with forceful, tight bass, front or down firing setup, and app based room correction, now discontinued.
A discontinued sealed 10 inch subwoofer with a 300 watt amp, multiple line inputs and an adjustable crossover.
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Specifications Side By Side
| MartinLogan Dynamo 1600X | JBL SUB 550P | |
|---|---|---|
| Price | $1,606.77 Discontinued | $600 Discontinued |
| Ranked | #3 of 212 in Medium Home Subwoofers (30-75 lbs) | #206 of 212 in Medium Home Subwoofers (30-75 lbs) |
| Enclosure | sealed | sealed |
| Output SPL at 15 Hz | 86.2 dB | - |
| Output SPL at 20 Hz | 99.4 dB | 84.7 dB |
| Output SPL at 25 Hz | 103.9 dB | 89.8 dB |
| Output SPL at 31.5 Hz | 111.7 dB | 98.1 dB |
| Output SPL at 40 Hz | 118.4 dB | 101.5 dB |
| Output SPL at 50 Hz | 121.0 dB | 103.2 dB |
| Output SPL at 63 Hz | 121.8 dB | 103.3 dB |
| Output SPL at 80 Hz | 121.0 dB | 103.7 dB |
| Output SPL at 100 Hz | 120.2 dB | 104.2 dB |
| Output SPL at 125 Hz | 119.0 dB | - |
| CEA-2010-A Average (40-80Hz) | 120.5 dB | 102.9 dB |
| Dimensions | 20.1”H x 17.9”W x 19.1”D (510.5 x 454.7 x 485.1 mm) | 17.5”H x 14.9”W x 15”D (444 x 379 x 380 mm) |
| Weight | 56 lbs (25.4 kg) | 50 lbs (22.7 kg) |
| Warranty | 3 | 1 |
| Cabinet Color | black | black |
| Country | United States | United States |
| Measurement Source | Audioholics | ErinsAudioCorner |
| Frequency Response | 20-200Hz, ±3dB | 27-150Hz |
| Amplifier Power | 900W RMS / 1800W peak | 300W RMS |
| Inputs | RCA (stereo and LFE), XLR (LFE), speaker-level (banana) | - |
| Drivers | 15” (381mm) driver | 10” (254mm) driver |
| XLR Input | Yes | - |
| RCA Input | Yes | - |
| TRS Input | No | - |
| Optical Input | No | - |
| Coaxial Input | No | - |
| USB Input | No | - |
| HDMI Input | No | - |
| AES Input | No | - |
| Aux Input | No | - |
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