Short answer: the Rythmik FV25HP. It ranks #22 of 110 subwoofers by sound quality at $2499; the BK Electronics Monolith-DF ranks #107 and costs $8995, so there is not much of a tradeoff to weigh.
What the Rythmik FV25HP offers: Independent CEA-2010 testing records 116.6 dB at 20 Hz and 126.2 dB through 40-80 Hz. The ported, front enclosure with 2x 15” (381mm) driver has the headroom for demanding film bass in a large room. Watch for: The 1054.1H x 533.4W x 558.8D mm cabinet and 95.3 kg mass make this a serious placement and moving commitment. Ported output does not solve room modes, so careful placement and calibration remain essential.
What the BK Electronics Monolith-DF offers: Independent CEA-2010 testing records 102.0 dB at 20 Hz and 108.4 dB through 40-80 Hz. The ported, bottom enclosure with 12” (305mm) driver with ported design delivers substantial upper-bass output for movie effects and music. Watch for: Deep-bass output is more limited than the strong 40-80 Hz result suggests, so it is not the right choice when the lowest movie effects are the priority. The 603.8H x 539.8W x 419.9D mm cabinet and 46.8 kg mass still require deliberate placement and calibration.
Buy the Rythmik FV25HP. It ranks higher for sound quality than the BK Electronics Monolith-DF and costs less, so there is no real case for the other one.
Skip the BK Electronics Monolith-DF if sound quality matters to you. It ranks near the bottom of the 110 subwoofers.
Looking for alternatives? See the complete Subwoofers rankings.
Specifications Side By Side
| Rythmik FV25HP | BK Electronics Monolith-DF | |
|---|---|---|
| Price | $2499 | $8995 |
| Ranked | #22 of 110 in Large Home Subwoofers (Over 75 lbs) | #107 of 110 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | ported, bottom |
| Output SPL at 10 Hz | 99.7 dB | - |
| Output SPL at 12.5 Hz | 108.4 dB | - |
| Output SPL at 15 Hz | 113.2 dB | 91.3 dB |
| Output SPL at 20 Hz | 116.6 dB | 102.0 dB |
| Output SPL at 25 Hz | 119.1 dB | 106.4 dB |
| Output SPL at 31.5 Hz | 122.4 dB | 108.3 dB |
| Output SPL at 40 Hz | 124.7 dB | 108.6 dB |
| Output SPL at 50 Hz | 126.1 dB | 108.7 dB |
| Output SPL at 63 Hz | 126.7 dB | 108.6 dB |
| Output SPL at 80 Hz | 127.3 dB | 107.7 dB |
| Output SPL at 100 Hz | 127.9 dB | - |
| Output SPL at 125 Hz | 127.8 dB | - |
| CEA-2010-A Average (40-80Hz) | 126.2 dB | 108.4 dB |
| Dimensions | 41.5"H x 21"W x 22"D (1054.1 x 533.4 x 558.8 mm) | 23.8"H x 21.3"W x 16.5"D (603.8 x 539.8 x 419.9 mm) |
| Weight | 210.1 lbs (95.3 kg) | 103.2 lbs (46.8 kg) |
| Warranty | 5/3 | 2 |
| Cabinet Color | black | black, wood |
| Country | United States | United Kingdom |
| Measurement Source | Data-bass | Ilkka Rissanen |
| Drivers | 2x 15" (381mm) driver | 12" (305mm) driver with ported design |
Related Speaker Comparisons
How Rythmik FV25HP compares with other leading options:
- Rythmik FV25HP vs Funk Audio Ultra 24.0
- Rythmik FV25HP vs JTR Speakers Growler (2015)
- Rythmik FV25HP vs Harbinger V2218S
- Rythmik FV25HP vs Funk Audio Classic 18.0
- Monoprice Monolith 16 THX Ultra vs Rythmik FV25HP
Prices on this page were last checked September 16, 2026 at 12:41 AM 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
Rythmik FV25HP: $2499 eBay
Pros: Independent CEA-2010 testing records 116.6 dB at 20 Hz and 126.2 dB through 40-80 Hz. The ported, front enclosure with 2x 15” (381mm) driver has the headroom for demanding film bass in a large room.
Cons: The 1054.1H x 533.4W x 558.8D mm cabinet and 95.3 kg mass make this a serious placement and moving commitment. Ported output does not solve room modes, so careful placement and calibration remain essential.
Full Rythmik FV25HP review and specifications →
| CEA-2010-A Average (40-80Hz) | 126.2 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 41.5"H x 21"W x 22"D (1054.1 x 533.4 x 558.8 mm) |
| Drivers | 2x 15" (381mm) driver |
| Enclosure | ported, front |
| Measurement Source | Data-bass |
| Output SPL at 10 Hz | 99.7 dB |
| Output SPL at 12.5 Hz | 108.4 dB |
| Output SPL at 15 Hz | 113.2 dB |
| Output SPL at 20 Hz | 116.6 dB |
| Output SPL at 25 Hz | 119.1 dB |
| Output SPL at 31.5 Hz | 122.4 dB |
| Output SPL at 40 Hz | 124.7 dB |
| Output SPL at 50 Hz | 126.1 dB |
| Output SPL at 63 Hz | 126.7 dB |
| Output SPL at 80 Hz | 127.3 dB |
| Output SPL at 100 Hz | 127.9 dB |
| Output SPL at 125 Hz | 127.8 dB |
| Warranty | 5/3 |
| Weight | 210.1 lbs (95.3 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by Data-bass; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
- Rythmik FV25HP vs Monoprice Monolith M-215
- Rythmik FV25HP vs Monoprice Monolith 16 THX Ultra
- Rythmik FV25HP vs JTR Speakers Captivator 1400
- Rythmik FV25HP vs Funk Audio Classic 18.0
- Rythmik FV25HP vs Harbinger V2218S
- Rythmik FV25HP vs JTR Speakers Growler (2015)
- Rythmik FV25HP vs Funk Audio Ultra 24.0
- Rythmik FV25HP vs Rythmik FV15HP
- See all 13 comparisons
BK Electronics Monolith-DF: $8995 eBay
Pros: Independent CEA-2010 testing records 102.0 dB at 20 Hz and 108.4 dB through 40-80 Hz. The ported, bottom enclosure with 12” (305mm) driver with ported design delivers substantial upper-bass output for movie effects and music.
Cons: Deep-bass output is more limited than the strong 40-80 Hz result suggests, so it is not the right choice when the lowest movie effects are the priority. The 603.8H x 539.8W x 419.9D mm cabinet and 46.8 kg mass still require deliberate placement and calibration.
Full BK Electronics Monolith-DF review and specifications →
| CEA-2010-A Average (40-80Hz) | 108.4 dB |
|---|---|
| Cabinet Color | black, wood |
| Country | United Kingdom |
| Dimensions | 23.8"H x 21.3"W x 16.5"D (603.8 x 539.8 x 419.9 mm) |
| Drivers | 12" (305mm) driver with ported design |
| Enclosure | ported, bottom |
| Measurement Source | Ilkka Rissanen |
| Output SPL at 15 Hz | 91.3 dB |
| Output SPL at 20 Hz | 102.0 dB |
| Output SPL at 25 Hz | 106.4 dB |
| Output SPL at 31.5 Hz | 108.3 dB |
| Output SPL at 40 Hz | 108.6 dB |
| Output SPL at 50 Hz | 108.7 dB |
| Output SPL at 63 Hz | 108.6 dB |
| Output SPL at 80 Hz | 107.7 dB |
| Warranty | 2 |
| Weight | 103.2 lbs (46.8 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by Ilkka Rissanen; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
- BK Electronics Monolith-DF vs SVS SB13-Plus
- BK Electronics Monolith-DF vs Genelec HTS4B
- BK Electronics Monolith-DF vs RSL (Rogersound Labs) Speedwoofer 12S
- BK Electronics Monolith-DF vs HSU Research VTF-3 MK3
- BK Electronics Monolith-DF vs Rythmik F18
- BK Electronics Monolith-DF vs SVS PB-4000
- BK Electronics Monolith-DF vs HSU Research VTF-3 MK5 HP
- BK Electronics Monolith-DF vs Rythmik FV15HP
- See all 16 comparisons