Short answer: the Harbinger V2218S for better sound quality, the Rythmik F18 for the lower price. The Harbinger V2218S ranks #15 of 110 subwoofers at $3495. The Rythmik F18 ranks #69 at $2344, $1151 cheaper.
What the Rythmik F18 offers: Independent CEA-2010 testing records 106.2 dB at 20 Hz and 119.5 dB through 40-80 Hz. The sealed enclosure with 18” (457mm) driver has the headroom for demanding film bass in a large room. Watch for: The 520.7H x 520.7W x 533.4D mm cabinet and 52.2 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks.
What the Harbinger V2218S offers: Independent CEA-2010 testing records 81.7 dB at 20 Hz and 128.9 dB through 40-80 Hz. The ported, front enclosure with 18” (457mm) driver delivers formidable 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 825.5H x 673.1W x 754.4D mm cabinet and 40.8 kg mass still require deliberate placement and calibration.
Buy the Rythmik F18 if the price matters more than sound quality. Buy the Harbinger V2218S if sound quality matters more than the price.
Still deciding? The full Subwoofers rankings cover every ranked option.
Specifications Side By Side
| Rythmik F18 | Harbinger V2218S | |
|---|---|---|
| Price | $1,850 | $3495 |
| Ranked | #69 of 110 in Large Home Subwoofers (Over 75 lbs) | #15 of 110 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | sealed | ported, front |
| 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 | 81.7 dB |
| Output SPL at 25 Hz | 110.9 dB | 99.7 dB |
| Output SPL at 31.5 Hz | 114.3 dB | 118.0 dB |
| Output SPL at 40 Hz | 117.1 dB | 122.8 dB |
| Output SPL at 50 Hz | 119.1 dB | 129.0 dB |
| Output SPL at 63 Hz | 120.5 dB | 132.2 dB |
| Output SPL at 80 Hz | 121.2 dB | 131.7 dB |
| Output SPL at 100 Hz | 121.4 dB | - |
| Output SPL at 125 Hz | 121.4 dB | - |
| CEA-2010-A Average (40-80Hz) | 119.5 dB | 128.9 dB |
| Dimensions | 20.5"H x 20.5"W x 21"D (520.7 x 520.7 x 533.4 mm) | 32.5"H x 26.5"W x 29.7"D (825.5 x 673.1 x 754.4 mm) |
| Weight | 115.1 lbs (52.2 kg) | 89.9 lbs (40.8 kg) |
| Warranty | 5/3 | - |
| Cabinet Color | black | black |
| Country | United States | United States |
| Measurement Source | Data-bass | Brent Butterworth |
| Drivers | 18" (457mm) driver | 18" (457mm) driver |
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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 F18: $1,850 Rythmik Audio eBay
Pros: Independent CEA-2010 testing records 106.2 dB at 20 Hz and 119.5 dB through 40-80 Hz. The sealed enclosure with 18” (457mm) driver has the headroom for demanding film bass in a large room.
Cons: The 520.7H x 520.7W x 533.4D mm cabinet and 52.2 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks.
Full Rythmik F18 review and specifications →
| 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"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) |
- 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 F18 vs Perlisten Audio R212s
- 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
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Harbinger V2218S: $3495 eBay
Pros: Independent CEA-2010 testing records 81.7 dB at 20 Hz and 128.9 dB through 40-80 Hz. The ported, front enclosure with 18” (457mm) driver delivers formidable 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 825.5H x 673.1W x 754.4D mm cabinet and 40.8 kg mass still require deliberate placement and calibration.
Notes: Looks like “PA sub”
Full Harbinger V2218S review and specifications →
| CEA-2010-A Average (40-80Hz) | 128.9 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 32.5"H x 26.5"W x 29.7"D (825.5 x 673.1 x 754.4 mm) |
| Drivers | 18" (457mm) driver |
| Enclosure | ported, front |
| Measurement Source | Brent Butterworth |
| Output SPL at 20 Hz | 81.7 dB |
| Output SPL at 25 Hz | 99.7 dB |
| Output SPL at 31.5 Hz | 118.0 dB |
| Output SPL at 40 Hz | 122.8 dB |
| Output SPL at 50 Hz | 129.0 dB |
| Output SPL at 63 Hz | 132.2 dB |
| Output SPL at 80 Hz | 131.7 dB |
| Weight | 89.9 lbs (40.8 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by Brent Butterworth; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
- Harbinger V2218S vs Funk Audio Classic 18.0
- Harbinger V2218S vs JTR Speakers Growler (2015)
- Harbinger V2218S vs Monoprice Monolith 16 THX Ultra
- Harbinger V2218S vs Funk Audio Ultra 24.0
- Harbinger V2218S vs Rythmik FV25HP
- Harbinger V2218S vs Monoprice Monolith M-215
- Harbinger V2218S vs JTR Speakers Captivator 1400
- Harbinger V2218S vs JTR Speakers Captivator 2400ULF
- See all 14 comparisons