Short answer: the Monoprice Monolith M-215 for the higher ranking, the Rythmik F18 for the lower price. The Monoprice Monolith M-215 ranks #18 of 97 subwoofers at $2500. The Rythmik F18 ranks #60 at $1850, $650 cheaper.
Buy the Monoprice Monolith M-215 if the ranking matters more than the price. Buy the Rythmik F18 if the price matters more than the ranking.
Specifications Side By Side
| Monoprice Monolith M-215 | Rythmik F18 | |
|---|---|---|
| Price | $2,500 | $1,850 |
| Ranked | #18 of 97 in Large Powered Home Subwoofers (Over 75 lbs) | #60 of 97 in Large Powered Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | sealed |
| Output SPL at 12.5 Hz | 103.9 dB | 97.4 dB |
| Output SPL at 15 Hz | 113.1 dB | 102.0 dB |
| Output SPL at 20 Hz | 118.9 dB | 106.2 dB |
| Output SPL at 25 Hz | 122.6 dB | 110.9 dB |
| Output SPL at 31.5 Hz | 125.2 dB | 114.3 dB |
| Output SPL at 40 Hz | 126.4 dB | 117.1 dB |
| Output SPL at 50 Hz | 126.1 dB | 119.1 dB |
| Output SPL at 63 Hz | 125.6 dB | 120.5 dB |
| Output SPL at 80 Hz | 125.6 dB | 121.2 dB |
| Output SPL at 100 Hz | 125.7 dB | 121.4 dB |
| Output SPL at 125 Hz | 126.3 dB | 121.4 dB |
| CEA-2010-A Average (40-80Hz) | 125.9 dB | 119.5 dB |
| Dimensions | 42.3"H x 20.0"W x 27.6"D (1074.4 x 508.0 x 701.0 mm) | 20.5"H x 20.5"W x 21.0"D (520.7 x 520.7 x 533.4 mm) |
| Weight | 216.1 lbs / 98.0 kg | 115.1 lbs / 52.2 kg |
| Warranty | 5 | 5/3 |
| Cabinet Color | black | black |
| Country | United States | United States |
| Measurement Source | Brent Butterworth | Data-bass |
| Drivers | 2x 15" (381mm) drivers | 18" (457mm) driver |
| Output SPL at 10 Hz | - | 93.7 dB |
The Two Speakers In Full
Monoprice Monolith M-215: $2,500
Notes: Product # 38543
| CEA-2010-A Average (40-80Hz) | 125.9 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 42.3"H x 20.0"W x 27.6"D (1074.4 x 508.0 x 701.0 mm) |
| Drivers | 2x 15" (381mm) drivers |
| Enclosure | ported, front |
| Measurement Source | Brent Butterworth |
| Output SPL at 12.5 Hz | 103.9 dB |
| Output SPL at 15 Hz | 113.1 dB |
| Output SPL at 20 Hz | 118.9 dB |
| Output SPL at 25 Hz | 122.6 dB |
| Output SPL at 31.5 Hz | 125.2 dB |
| Output SPL at 40 Hz | 126.4 dB |
| Output SPL at 50 Hz | 126.1 dB |
| Output SPL at 63 Hz | 125.6 dB |
| Output SPL at 80 Hz | 125.6 dB |
| Output SPL at 100 Hz | 125.7 dB |
| Output SPL at 125 Hz | 126.3 dB |
| Warranty | 5 |
| Weight | 216.1 lbs / 98.0 kg |
- Head-to-Head Comparisons
- Monoprice Monolith M-215 vs Reaction Audio PV-15X
- Monoprice Monolith M-215 vs Monoprice Monolith 16 THX Ultra
- Monoprice Monolith M-215 vs JTR Speakers Captivator S2
- Monoprice Monolith M-215 vs JTR Speakers Captivator 4000ULF
- Monoprice Monolith M-215 vs Power Sound Audio (PSA) TRIAX
- Monoprice Monolith M-215 vs JTR Speakers Orbit Shifter LFU
- Monoprice Monolith M-215 vs JTR Speakers Orbit Shifter PRO
- Monoprice Monolith M-215 vs Rythmik FV15HP
- See all 14 comparisons
- Links
Rythmik F18: $1,850
| CEA-2010-A Average (40-80Hz) | 119.5 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 20.5"H x 20.5"W x 21.0"D (520.7 x 520.7 x 533.4 mm) |
| Drivers | 18" (457mm) driver |
| Enclosure | sealed |
| Measurement Source | Data-bass |
| Output SPL at 10 Hz | 93.7 dB |
| Output SPL at 12.5 Hz | 97.4 dB |
| Output SPL at 15 Hz | 102.0 dB |
| Output SPL at 20 Hz | 106.2 dB |
| Output SPL at 25 Hz | 110.9 dB |
| Output SPL at 31.5 Hz | 114.3 dB |
| Output SPL at 40 Hz | 117.1 dB |
| Output SPL at 50 Hz | 119.1 dB |
| Output SPL at 63 Hz | 120.5 dB |
| Output SPL at 80 Hz | 121.2 dB |
| Output SPL at 100 Hz | 121.4 dB |
| Output SPL at 125 Hz | 121.4 dB |
| Warranty | 5/3 |
| Weight | 115.1 lbs / 52.2 kg |
- Head-to-Head Comparisons
- Rythmik F18 vs Monoprice Monolith M15-S
- Rythmik F18 vs Monoprice Monolith M-15 V2
- Rythmik F18 vs SVS PB-4000
- Rythmik F18 vs HSU Research VTF-3 MK5 HP
- Rythmik F18 vs HSU Research VTF-15H MK2
- Rythmik F18 vs Rythmik FV15HP
- Rythmik F18 vs Reaction Audio PV-15X
- Rythmik F18 vs Monoprice Monolith 16 THX Ultra
- See all 13 comparisons
- Links
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Product prices and availability were last checked August 9, 2026 at 6:57 AM UTC 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.