Short answer: both are discontinued, so this only matters if you are buying used. Used, the JTR Speakers Growler (2015) is the better pick: it ranks #13 of 143 subwoofers by sound quality (rated 4.5/5), against #141 (rated 3.3/5) for the BK Electronics Monolith-DF. If you want one new, the JTR Speakers Orbit Shifter PRO ranks #1 at $4,499.
What the BK Electronics Monolith-DF does well: Independent CEA-2010 testing records 102.0 dB at 20 Hz and 108.4 dB through 40-80 Hz. 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 JTR Speakers Growler (2015) is the better-sounding pick. 12-inch ported driver reaches 130.2dB CEA-2010-A average, nearly matching the class leader for about $1,000 less. The tradeoff: Ported design room interaction, 99.2 lbs (45 kg) size, and $2995 cost.
Buy the JTR Speakers Growler (2015) only if you find one used in good condition; both are discontinued, and it is the better rated of the two. For a new speaker, start with the JTR Speakers Orbit Shifter PRO instead.
Still deciding? The full Subwoofers rankings cover every ranked option.
Specifications Side By Side
| BK Electronics Monolith-DF | JTR Speakers Growler (2015) | |
|---|---|---|
| Price | £406.95 Discontinued | $2,995 Passive, Discontinued |
| Ranked | #141 of 143 in Large Home Subwoofers (Over 75 lbs) | #13 of 143 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, bottom | ported, front |
| Output SPL at 15 Hz | 91.3 dB | - |
| Output SPL at 20 Hz | 102.0 dB | 92.8 dB |
| Output SPL at 25 Hz | 106.4 dB | 97.2 dB |
| Output SPL at 31.5 Hz | 108.3 dB | 106.6 dB |
| Output SPL at 40 Hz | 108.6 dB | 122.7 dB |
| Output SPL at 50 Hz | 108.7 dB | 130.0 dB |
| Output SPL at 63 Hz | 108.6 dB | 133.6 dB |
| Output SPL at 80 Hz | 107.7 dB | 134.4 dB |
| CEA-2010-A Average (40-80Hz) | 108.4 dB | 130.2 dB |
| Dimensions | 23.8”H x 21.3”W x 16.5”D (603.8 x 539.8 x 419.9 mm) | 22.5”H x 30”W x 20”D (571.5 x 762.0 x 508.0 mm) |
| Weight | 103.2 lbs (46.8 kg) | 100.1 lbs (45.4 kg) |
| Warranty | 2 | 5 years |
| Cabinet Color | black, wood | - |
| Country | United Kingdom | United States |
| Measurement Source | Ilkka Rissanen | Data-bass |
| Drivers | 12” (305mm) driver with ported design | 12” (305mm) driver |
| Inputs | XLR (balanced), RCA (unbalanced) | - |
| 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 | - |
| Passive | - | Yes |
| Output SPL at 100 Hz | - | 135.5 dB |
| Output SPL at 125 Hz | - | 136.0 dB |
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Prices on this page were last checked October 14, 2026 at 2:38 PM 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
BK Electronics Monolith-DF: £406.95 Discontinued 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. Discontinued.
Full BK Electronics Monolith-DF review and specifications →
| AES Input | No |
|---|---|
| Aux Input | No |
| CEA-2010-A Average (40-80Hz) | 108.4 dB |
| Cabinet Color | black, wood |
| Coaxial Input | No |
| 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 |
| HDMI Input | No |
| Inputs | XLR (balanced), RCA (unbalanced) |
| Measurement Source | Ilkka Rissanen |
| Optical Input | No |
| 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 |
| RCA Input | Yes |
| TRS Input | No |
| USB Input | No |
| Warranty | 2 |
| Weight | 103.2 lbs (46.8 kg) |
| XLR Input | Yes |
- 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
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JTR Speakers Growler (2015): $2,995 Passive Discontinued eBay
Pros: 12-inch ported driver reaches 130.2dB CEA-2010-A average, nearly matching the class leader for about $1,000 less.
Cons: Ported design room interaction, 45 kg size, and $2995 cost. Discontinued.
Notes: Looks like “PA sub”
Full JTR Speakers Growler (2015) review and specifications →
| Released | 2015 (11 years ago) |
|---|---|
| CEA-2010-A Average (40-80Hz) | 130.2 dB |
| Country | United States |
| Dimensions | 22.5”H x 30”W x 20”D (571.5 x 762.0 x 508.0 mm) |
| Drivers | 12” (305mm) driver |
| Enclosure | ported, front |
| Measurement Source | Data-bass |
| Output SPL at 20 Hz | 92.8 dB |
| Output SPL at 25 Hz | 97.2 dB |
| Output SPL at 31.5 Hz | 106.6 dB |
| Output SPL at 40 Hz | 122.7 dB |
| Output SPL at 50 Hz | 130.0 dB |
| Output SPL at 63 Hz | 133.6 dB |
| Output SPL at 80 Hz | 134.4 dB |
| Output SPL at 100 Hz | 135.5 dB |
| Output SPL at 125 Hz | 136.0 dB |
| Passive | Yes |
| Warranty | 5 years |
| Weight | 100.1 lbs (45.4 kg) |
- 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
- JTR Speakers Growler (2015) vs Danley Sound Labs DTS10
- JTR Speakers Growler (2015) vs Harbinger V2218S
- JTR Speakers Growler (2015) vs Funk Audio Ultra 24.0
- JTR Speakers Growler (2015) vs JTR Speakers Captivator S2
- JTR Speakers Growler (2015) vs Funk Audio Classic 18.0
- JTR Speakers Growler (2015) vs Monoprice Monolith 16 THX Ultra
- JTR Speakers Growler (2015) vs Pro Audio Technology LFC-24sm
- JTR Speakers Growler (2015) vs Reaction Audio PV-15X
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