RSL (Rogersound Labs) Speedwoofer 12S vs BK Electronics Monolith-DF

Last updated: September 16, 2026

Short answer: the RSL (Rogersound Labs) Speedwoofer 12S. It ranks #98 of 110 subwoofers by sound quality at $800; the BK Electronics Monolith-DF ranks #107 and costs $8995, which makes this an easy call rather than a real tradeoff.

RSL (Rogersound Labs) Speedwoofer 12S vs BK Electronics Monolith-DF

What the RSL (Rogersound Labs) Speedwoofer 12S offers: Independent CEA-2010 testing records 109.3 dB at 20 Hz and 113.2 dB through 40-80 Hz. The ported, rear enclosure with 12” (305mm) driver has the headroom for demanding film bass in a large room. Watch for: The 565.1H x 479.4W x 562.0D mm cabinet and 37.2 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 RSL (Rogersound Labs) Speedwoofer 12S. It ranks higher for sound quality than the BK Electronics Monolith-DF and costs less, which settles it without a real tradeoff to make.

If sound quality matters at all to you, skip both of these and look higher up the 110 subwoofers instead.

Looking for alternatives? See the complete Subwoofers rankings.

Specifications Side By Side

RSL (Rogersound Labs) Speedwoofer 12S BK Electronics Monolith-DF
Price$800$8995
Ranked#98 of 110 in Large Home Subwoofers (Over 75 lbs)#107 of 110 in Large Home Subwoofers (Over 75 lbs)
Enclosureported, rearported, bottom
Output SPL at 15 Hz104.4 dB91.3 dB
Output SPL at 20 Hz109.3 dB102.0 dB
Output SPL at 25 Hz110.9 dB106.4 dB
Output SPL at 31.5 Hz112.5 dB108.3 dB
Output SPL at 40 Hz113.4 dB108.6 dB
Output SPL at 50 Hz113.4 dB108.7 dB
Output SPL at 63 Hz113.0 dB108.6 dB
Output SPL at 80 Hz113.1 dB107.7 dB
Output SPL at 100 Hz112.2 dB-
CEA-2010-A Average (40-80Hz)113.2 dB108.4 dB
Dimensions22.2"H x 18.9"W x 22.1"D (565.1 x 479.4 x 562.0 mm)23.8"H x 21.3"W x 16.5"D (603.8 x 539.8 x 419.9 mm)
Weight82 lbs (37.2 kg)103.2 lbs (46.8 kg)
Warranty?2
Cabinet Colorblack, whiteblack, wood
CountryUnited StatesUnited Kingdom
Measurement SourceErinsAudioCornerIlkka Rissanen
Drivers12" (305mm) driver12" (305mm) driver with ported design

More top alternatives to RSL (Rogersound Labs) Speedwoofer 12S:

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

RSL (Rogersound Labs) Speedwoofer 12S: $800 eBay

RSL (Rogersound Labs) Speedwoofer 12S ranking card

Pros: Independent CEA-2010 testing records 109.3 dB at 20 Hz and 113.2 dB through 40-80 Hz. The ported, rear enclosure with 12” (305mm) driver has the headroom for demanding film bass in a large room.

Cons: The 565.1H x 479.4W x 562.0D mm cabinet and 37.2 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 RSL (Rogersound Labs) Speedwoofer 12S review and specifications →

CEA-2010-A Average (40-80Hz)113.2 dB
Cabinet Colorblack, white
CountryUnited States
Dimensions22.2"H x 18.9"W x 22.1"D (565.1 x 479.4 x 562.0 mm)
Drivers12" (305mm) driver
Enclosureported, rear
Measurement SourceErinsAudioCorner
Output SPL at 15 Hz104.4 dB
Output SPL at 20 Hz109.3 dB
Output SPL at 25 Hz110.9 dB
Output SPL at 31.5 Hz112.5 dB
Output SPL at 40 Hz113.4 dB
Output SPL at 50 Hz113.4 dB
Output SPL at 63 Hz113.0 dB
Output SPL at 80 Hz113.1 dB
Output SPL at 100 Hz112.2 dB
Warranty?
Weight82 lbs (37.2 kg)
Search eBay for RSL (Rogersound Labs) Speedwoofer 12S →

BK Electronics Monolith-DF: $8995 eBay

BK Electronics Monolith-DF ranking card

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 Colorblack, wood
CountryUnited Kingdom
Dimensions23.8"H x 21.3"W x 16.5"D (603.8 x 539.8 x 419.9 mm)
Drivers12" (305mm) driver with ported design
Enclosureported, bottom
Measurement SourceIlkka Rissanen
Output SPL at 15 Hz91.3 dB
Output SPL at 20 Hz102.0 dB
Output SPL at 25 Hz106.4 dB
Output SPL at 31.5 Hz108.3 dB
Output SPL at 40 Hz108.6 dB
Output SPL at 50 Hz108.7 dB
Output SPL at 63 Hz108.6 dB
Output SPL at 80 Hz107.7 dB
Warranty2
Weight103.2 lbs (46.8 kg)
Search eBay for BK Electronics Monolith-DF →