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WifeLeaver 14.8K Views
Apr 30, 2026 12:48 PM

Monoprice Monolith M12 v2 subwoofer $300

$300

$1,000

70% off
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Community Reviews

The Monolith M12 v2 is a huge, heavy subwoofer that delivers serious bass and looks like a standout value for the output. Setup reports describe clean, punchy low end, strong performance in surround systems, and enough headroom to get loud once calibrated correctly. The main catch is power, since this EU and UK version is 220 to 240 volt and needs a transformer, dedicated 240 volt wiring, or a hardware conversion to run on US power. It is a bargain if you can handle the electrical side and the size.

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94 Comments

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Apr 30, 2026 5:32 PM
144 Comments
Joined Apr 2008
sweetnamjaApr 30, 2026 5:32 PM
144 Comments
Bought one! What wattage converter would we need for this?
Last edited by sweetnamja April 30, 2026 at 10:35 AM.
Apr 30, 2026 5:39 PM
4K Comments
Joined May 2013
MoisesA7010Apr 30, 2026 5:39 PM
4K Comments
new tech discussion on this
https://www.audiosciencereview.co...own.71065/

This will be sub deal of the year
Apr 30, 2026 5:57 PM
4K Comments
Joined May 2013
MoisesA7010Apr 30, 2026 5:57 PM
4K Comments
I called Monoprice product support, they said this sub works at either 220 or 240 and 50 or 60 hz... US is 60 hz so you can step up the voltage only and should be fine. 3000 watts transformer should ensure the sub is always getting enough power. Transformers are approx 100.00. 400 total + tax is a great deal for this sub. Ordered.
Apr 30, 2026 5:57 PM
4.6K Comments
Joined Mar 2006
tqlla3kApr 30, 2026 5:57 PM
4.6K Comments
Quote from MoisesA7010 View quoted comment :
a lot of the converters support 50/60hz
The ones that I see in the $100 range only convert the voltage. I am not sure how 60hz would affect the subwoofer.

https://www.amazon.com/dp/B0DJ27SNYB/

I dont know much about these converters, so please let me know what will work.
Apr 30, 2026 6:00 PM
4K Comments
Joined May 2013
MoisesA7010Apr 30, 2026 6:00 PM
4K Comments
Quote from IDAnonymous View quoted comment :
Can you send me links for converters that work for this subwoofer use case. If link is blocked, just give me names to search on amazon. I am seeing $1000 converters
Any that does 1000watt. Should be no more than $100 on amazon
Apr 30, 2026 6:01 PM
4K Comments
Joined May 2013
MoisesA7010Apr 30, 2026 6:01 PM
4K Comments
Quote from tqlla3k View quoted comment :
The ones that I see in the $100 range only convert the voltage. I am not sure how 60hz would affect the subwoofer.

https://www.amazon.com/dp/B0DJ27SNYB/

I dont know much about these converters, so please let me know what will work.
no need to worry about 50/60hz conversion.

Right on the question section, monprice said:

BEST ANSWER: Hi, thank you for your inquiry. Since this is EU/UK version, this requires 220‑240 V, 50/60 Hz. I hope this helps.

so it does 50/60. All you need is the transformer which is no more than $100 on amazon
Apr 30, 2026 6:26 PM
649 Comments
Joined Oct 2007
TheMasterApr 30, 2026 6:26 PM
649 Comments
Or wire up a 240v outlet and use this:

https://a.co/d/0gaOAgM9

EDIT: Some receptacles will not play nice with that plug. Some common 240V receptacles have a rejection style ground that will not allow a round ground pin to enter the receptacle. Below is a link to a $4 Amazon plug you can use on a typical home depot 240V receptacle. Just cut off the end of one of the provided Monprice cables and attach this plug. This is definitely the low-cost solution to make the subwoofer work in the US without the eyesore of a transformer (provided you have access to rewire one of the outlets in your room for 240V from your panelboard.

https://www.amazon.com/dp/B0F5Q1X...title&th=1

Note that there is no ground connection on this subwoofer, so don't be surprised if you don't see a ground conductor in the cutoff end of the Monoprice cable!
Last edited by TheMaster May 11, 2026 at 06:42 AM.

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Apr 30, 2026 8:04 PM
874 Comments
Joined Apr 2016
He-ManApr 30, 2026 8:04 PM
874 Comments
Quote from lilbabykenny View quoted comment :
Is the female end of the plug different than the us? Because if it's the same, would it not be as simple as buying a US cord? I've bought longer cords 3rd party for my 15" v1's instead of using an extension cord.
Its not simply swapping cords. The circuit board is designed to operate only at 220v and not at 120v for US. And no, there is no option onboard to switch the voltage to 120v.
Apr 30, 2026 9:12 PM
1.4K Comments
Joined Jun 2010
IDAnonymousApr 30, 2026 9:12 PM
1.4K Comments
I have a Monolith 15 V1, so I'd only be adding one Monolith 12 to pair with it. I know they don't match in size, but I'm hoping Dirac ART can make it work well...
Last edited by IDAnonymous April 30, 2026 at 04:13 PM.
Apr 30, 2026 10:12 PM
164 Comments
Joined Mar 2008
ryanmackApr 30, 2026 10:12 PM
164 Comments

Our community has rated this post as helpful. If you agree, why not thank

The whole conversation is regarding the conversion. Poster should add (EU/UK PLUG) to the title.
2
Apr 30, 2026 10:28 PM
1.2K Comments
Joined Nov 2006
benedictApr 30, 2026 10:28 PM
1.2K Comments
ordered this along with the voltage step up converter. thanks op!
Apr 30, 2026 11:08 PM
221 Comments
Joined Dec 2019
MemorableBorder5484Apr 30, 2026 11:08 PM
221 Comments
I saw screenshots on Reddit showing the amp only supports 50hz. Meaning a $100 Amazon step up transformer will not work
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Apr 30, 2026 11:27 PM
1.9K Comments
Joined Apr 2014
WifeLeaverApr 30, 2026 11:27 PM
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1.9K Comments
Quote from ryanmack View quoted comment :
The whole conversation is regarding the conversion. Poster should add (EU/UK PLUG) to the title.
Done. Hope the sub works out well with voltage transformers. Usually 50/60hz frequency is not a big deal
Its been a good while we had a Monolith sub deal, enjoy
Apr 30, 2026 11:32 PM
1.2K Comments
Joined Nov 2006
benedictApr 30, 2026 11:32 PM
1.2K Comments

Our community has rated this post as helpful. If you agree, why not thank

Quote from MemorableBorder5484 View quoted comment :
I saw screenshots on Reddit showing the amp only supports 50hz. Meaning a $100 Amazon step up transformer will not work
i plugged it into an AI tool and bottom line, it should be fine even if the amp only supports 50hz.

fwiw

What to watch for
Frequency (Hz) — the bigger concern
  • US power is 60Hz, EU/UK is 50Hz
  • A step-up transformer outputs 240V but still at 60Hz
  • For a subwoofer with a switching power supply (SMPS) — which most modern powered subs use — this is a non-issue. SMPS designs are frequency-agnostic
  • For a sub with a linear/toroidal power supply, 60Hz instead of 50Hz is actually better — transformers run cooler and more efficiently at higher frequency
The Monoprice Monolith THX subs are sold in the US at 120V, so if this is a different brand's 240V unit, check the manual or back panel for the power supply type.
Transformer sizing
  • The Monolith THX 12" draws around 300-400W at peaks
  • Get a transformer rated for at least 2× the device's wattage — so minimum 800VA, ideally 1000VA+ for headroom
  • Undersized transformers will run hot, clip, and potentially damage the sub or themselves
Plug/socket adapter
You'll also need an IEC or plug adapter to match the EU/UK plug to your transformer's outlet — just a mechanical fit issue, no electrical concern.
Bottom line

Yes, it'll work fine. Just size the transformer generously (1000VA+) and you're good.
You said: so i don't need to worry about frequency?

so i don't need to worry about frequency?
4:30 PM
Claude responded: Correct — don't worry about it.

Correct — don't worry about it.
The Monolith THX 12" uses a switching power supply, and SMPS units internally convert AC to DC immediately and regulate from there. They don't care whether the incoming AC is 50Hz or 60Hz — they work fine anywhere from 50–60Hz (many are even rated 47–63Hz).
The 50/60Hz sensitivity issue really only matters for:
  • Old motors (turntables, tape decks) where speed is tied to AC frequency
  • Older linear power supplies with large toroidal transformers that are tuned to a specific frequency
A powered subwoofer amp in 2024 is almost certainly switching supply. You're fine.
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Apr 30, 2026 11:49 PM
3.7K Comments
Joined Mar 2006
eduardmcApr 30, 2026 11:49 PM
3.7K Comments
I have the 10" v2 version. Got it a few years refurbished for $240 on monoprice. Is a monster. To much for me since I live in an apartment. Had to tone it down. It comes with port plugs to run it sealed. Havent had any amps problem. Beware.. this is big, my 10" was close to 100lbs and enclosure seems to be made for a 12- 15" on how big it is.

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