Short answer: the Funk Audio Custom 21.0 if sound quality matters most, the Monoprice Monolith 16 THX Ultra if price matters most. The Funk Audio Custom 21.0 ranks #12 of 110 subwoofers at $6061.91. The Monoprice Monolith 16 THX Ultra ranks #18 at $2300, $3761.91 cheaper.
What the Monoprice Monolith 16 THX Ultra offers: 16-inch ported driver and THX Ultra certification deliver 126.5dB CEA-2010-A average at a fraction of the price of the subwoofers ranked above it. Watch for: Heavy at 78 kg and ported design can interact with room acoustics.
What the Funk Audio Custom 21.0 offers: Independent CEA-2010 testing records 109.8 dB at 20 Hz and 127.7 dB through 40-80 Hz. The sealed enclosure with 21” (533mm) driver has the headroom for demanding film bass in a large room. Watch for: The 577.9H x 565.1W x 520.7D mm cabinet and 65.8 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks.
Buy the Monoprice Monolith 16 THX Ultra when the price outweighs sound quality for you, and the Funk Audio Custom 21.0 when sound quality outweighs the price instead.
Want more options? Browse the full Subwoofers rankings.
Specifications Side By Side
| Monoprice Monolith 16 THX Ultra | Funk Audio Custom 21.0 | |
|---|---|---|
| Price | $2,300 | $6,061.91 |
| Ranked | #18 of 110 in Large Home Subwoofers (Over 75 lbs) | #12 of 110 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | sealed |
| Output SPL at 15 Hz | 107.3 dB | 105.7 dB |
| Output SPL at 20 Hz | 118.4 dB | 109.8 dB |
| Output SPL at 25 Hz | 123.3 dB | 114.2 dB |
| Output SPL at 31.5 Hz | 125.1 dB | 120.4 dB |
| Output SPL at 40 Hz | 126.3 dB | 124.1 dB |
| Output SPL at 50 Hz | 126.5 dB | 126.8 dB |
| Output SPL at 63 Hz | 126.6 dB | 129.0 dB |
| Output SPL at 80 Hz | 126.8 dB | 131.0 dB |
| Output SPL at 100 Hz | 127.2 dB | 132.6 dB |
| Output SPL at 125 Hz | 127.6 dB | 133.0 dB |
| CEA-2010-A Average (40-80Hz) | 126.5 dB | 127.7 dB |
| Dimensions | 25.6"H x 22"W x 28.1"D (650.2 x 558.8 x 713.7 mm) | 22.8"H x 22.2"W x 20.5"D (577.9 x 565.1 x 520.7 mm) |
| Weight | 171.5 lbs (77.8 kg) | 145.1 lbs (65.8 kg) |
| Warranty | 5 | 3 |
| Cabinet Color | black | wood, custom |
| Country | United States | Canada |
| Measurement Source | Audioholics | Data-bass |
| Drivers | 16" (406mm) driver | 21" (533mm) driver |
| Output SPL at 10 Hz | - | 97.4 dB |
| Output SPL at 12.5 Hz | - | 101.1 dB |
Related Speaker Comparisons
How Funk Audio Custom 21.0 compares with other leading options:
- Funk Audio Custom 21.0 vs Power Sound Audio (PSA) V3600I
- Funk Audio Custom 21.0 vs Funk Audio Ultra 24.0
- Funk Audio Classic 18.0 vs Funk Audio Custom 21.0
- Funk Audio Custom 21.0 vs Harbottle Audio C24 L2
- Monoprice Monolith 16 THX Ultra vs Power Sound Audio (PSA) S3600i
Prices on this page were last checked September 14, 2026 at 1:47 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
Monoprice Monolith 16 THX Ultra: $2,300 eBay
Pros: 16-inch ported driver and THX Ultra certification deliver 126.5dB CEA-2010-A average at a fraction of the price of the subwoofers ranked above it.
Cons: Heavy at 78 kg and ported design can interact with room acoustics.
Notes: Product # 42031
Full Monoprice Monolith 16 THX Ultra review and specifications →
| CEA-2010-A Average (40-80Hz) | 126.5 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 25.6"H x 22"W x 28.1"D (650.2 x 558.8 x 713.7 mm) |
| Drivers | 16" (406mm) driver |
| Enclosure | ported, front |
| Measurement Source | Audioholics |
| Output SPL at 15 Hz | 107.3 dB |
| Output SPL at 20 Hz | 118.4 dB |
| Output SPL at 25 Hz | 123.3 dB |
| Output SPL at 31.5 Hz | 125.1 dB |
| Output SPL at 40 Hz | 126.3 dB |
| Output SPL at 50 Hz | 126.5 dB |
| Output SPL at 63 Hz | 126.6 dB |
| Output SPL at 80 Hz | 126.8 dB |
| Output SPL at 100 Hz | 127.2 dB |
| Output SPL at 125 Hz | 127.6 dB |
| Warranty | 5 |
| Weight | 171.5 lbs (77.8 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by Audioholics; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
- Monoprice Monolith 16 THX Ultra vs Harbottle Audio C24 L2
- Monoprice Monolith 16 THX Ultra vs Funk Audio Ultra 21.0LX
- Monoprice Monolith 16 THX Ultra vs Funk Audio Classic 18.0
- Monoprice Monolith 16 THX Ultra vs JTR Speakers Captivator 2400
- Monoprice Monolith 16 THX Ultra vs Reaction Audio PV-15X
- Monoprice Monolith 16 THX Ultra vs Harbinger V2218S
- Monoprice Monolith 16 THX Ultra vs Danley Sound Labs DTS10
- Monoprice Monolith 16 THX Ultra vs Rythmik FV25HP
- See all 54 comparisons
Funk Audio Custom 21.0: $6,061.91 eBay
Pros: Independent CEA-2010 testing records 109.8 dB at 20 Hz and 127.7 dB through 40-80 Hz. The sealed enclosure with 21” (533mm) driver has the headroom for demanding film bass in a large room.
Cons: The 577.9H x 565.1W x 520.7D mm cabinet and 65.8 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks.
Notes: Data-bass labeled this sub as ‘FW21.0’, but original name is 21.0
Full Funk Audio Custom 21.0 review and specifications →
| CEA-2010-A Average (40-80Hz) | 127.7 dB |
|---|---|
| Cabinet Color | wood, custom |
| Country | Canada |
| Dimensions | 22.8"H x 22.2"W x 20.5"D (577.9 x 565.1 x 520.7 mm) |
| Drivers | 21" (533mm) driver |
| Enclosure | sealed |
| Measurement Source | Data-bass |
| Output SPL at 10 Hz | 97.4 dB |
| Output SPL at 12.5 Hz | 101.1 dB |
| Output SPL at 15 Hz | 105.7 dB |
| Output SPL at 20 Hz | 109.8 dB |
| Output SPL at 25 Hz | 114.2 dB |
| Output SPL at 31.5 Hz | 120.4 dB |
| Output SPL at 40 Hz | 124.1 dB |
| Output SPL at 50 Hz | 126.8 dB |
| Output SPL at 63 Hz | 129.0 dB |
| Output SPL at 80 Hz | 131.0 dB |
| Output SPL at 100 Hz | 132.6 dB |
| Output SPL at 125 Hz | 133.0 dB |
| Warranty | 3 |
| Weight | 145.1 lbs (65.8 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