Monolith by Monoprice M15-S 15" THX Ultra Certified Sealed 1000-Watt Powered Subwoofer
Product # 35141
$1,299.99
This item has been discontinued
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I've got the 3-ported predecessor to this. Why would I want this one?
Mike E
on Mar 16, 2019

Monolith by Monoprice M15-S 15" THX Ultra Certified Sealed 1000-Watt Powered Subwoofer

Monolith by Monoprice 15in THX Ultra Certified 1000-Watt Subwoofer Amplifier
BEST ANSWER: Sealed subs offer lower Q at the expense of bass extension. For the same output level at a given frequency, they have to be bigger. Arguably, they are more "musical" in the sense that they have a lower Q: they are "tighter". The bass is less "muddy" and less "boomy", desirable qualities for music. Q is a measure of the "resonance" of the sub. A sub that resonates will be "boomy" and "muddy". So, lower Q is good: 0.707 (half of the square root of two) is "critically damped", about as high as you want to go, though more Q will give you more output at lower frequencies. See the dilema? Higher Q means louder but not as clean. A Q of 0.6 is considered good for a "musical" or "accurate" sub, and my preference.
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- Rene H on Jun 19, 2019
BEST ANSWER: Sealed subs offer lower Q at the expense of bass extension. For the same output level at a given frequency, they have to be bigger. Arguably, they are more "musical" in the sense that they have a lower Q: they are "tighter". The bass is less "muddy" and less "boomy", desirable qualities for music. Q is a measure of the "resonance" of the sub. A sub that resonates will be "boomy" and "muddy". So, lower Q is good: 0.707 (half of the square root of two) is "critically damped", about as high as you want to go, though more Q will give you more output at lower frequencies. See the dilema? Higher Q means louder but not as clean. A Q of 0.6 is considered good for a "musical" or "accurate" sub, and my preference.
- Reply
- Inaccurate
- Rene H on Jun 19, 2019
If you have the ported model, like I do, then there is no reason at all. A sealed sub may be better for when you are mainly playing music rather than movies as you don't need the more "tactile" feel of the ports' airflow. Some believe sealed subs are more accurate than ported, though you lose the reproduction of some of the lowest frequencies. Unless you're playing pipe organ music a lot, you may never miss them.
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- Dan H on Mar 16, 2019
Not sure you would. The big debate between ported and non-ported is to do with the type of music/movies and the ratios you listen to them.
I have the 15" THX with two-ports plugged - it rocks our 'great room' - but I have over 11k cubic feet to fill and open to kitchen on one side
I have the 15" THX with two-ports plugged - it rocks our 'great room' - but I have over 11k cubic feet to fill and open to kitchen on one side
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- patrick m on Mar 16, 2019
No, I don’t think specs wise there is any difference. Comparing the two it seems more cosmetic than sound quality difference. I prefer 3 ported than the new one.
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- Ironnerve on Mar 16, 2019
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Is this made in usa like the amps?
A shopper
on Aug 14, 2019
BEST ANSWER: No, it is not. This is designed and engineered in the USA, but manufactured in China.
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- New User U Staff on Aug 14, 2019
BEST ANSWER: No, it is not. This is designed and engineered in the USA, but manufactured in China.
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- New User U Staff on Aug 14, 2019
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Can this Sub be put on its side without issues? Should it be placed on anything or is carpet with padding fine?
FRANK D
on Sep 1, 2019
BEST ANSWER: Thank you for your question.
You can place it on its side on carpet if you would like.
You can place it on its side on carpet if you would like.
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- Tyler C Staff on Oct 3, 2019
BEST ANSWER: Thank you for your question.
You can place it on its side on carpet if you would like.
You can place it on its side on carpet if you would like.
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- Tyler C Staff on Oct 3, 2019
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Regarding the Monolith M15-S, does the 23.5 inch height measurement include
the rubber feet?
the rubber feet?
Toby B
on Jan 13, 2020
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Does monoprice offer any kind of in home trial period (ex: 30 day or 45 day money back) guarantee on their subwoofers similar to others in the subwoofer industry (SVS, PSA, HSU, etc)?
Daniel J
on Feb 24, 2020
BEST ANSWER: Thank you for your question.
All of the non 3rd party products we sell have a 30 day refund policy.
All of the non 3rd party products we sell have a 30 day refund policy.
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- Tyler C Staff on Feb 25, 2020
BEST ANSWER: Thank you for your question.
All of the non 3rd party products we sell have a 30 day refund policy.
All of the non 3rd party products we sell have a 30 day refund policy.
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- Tyler C Staff on Feb 25, 2020
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Can a preamp xlr out and a A/V receiver LFE out both be connected to this sub at the same time without issues? Receiver used for HT and pre used for music.
Todd S
on Jun 13, 2020
When will you have more of these in stock?
A shopper
on Oct 2, 2020
Can the onboard low-pass filter be bypassed? If so, when bypassed, how does the frequency response differ above 200Hz?
Rick J
on Jan 4, 2021

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Reviews
5.0 / 5.0
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Rated 5 out of 5
Monolith THX line makes it easy to create a REAL Home Theater
I started with THX-365C (center channel speaker) and (2) THX-365 T and this subwoofer which sounded fabulous but made me realize that my other speakers couldn't keep up. I didn't want to spend a lot of money on the surrounds with the THX-265 so I tried using less expensive speakers as satellites.
Comparing this speaker line to those from another company that sells speakers direct to consumer really illustrated how phenomenal these speakers are. In a home theater set-up you may not notice much of a difference but for music these really shine. THX-265 complements the setup very well. Music sounds rich, silky, smooth. Listening to Michael Kiwanuka "Solid Ground" was such a moving experience I realized that I just will not be satisfied with anything else.
This is all without using the Atmos speaker features that these have. Instead I opted for the Alpha 8" directional in-ceiling speaker which are awesome and integrates very well into the mix.
Comparing this speaker line to those from another company that sells speakers direct to consumer really illustrated how phenomenal these speakers are. In a home theater set-up you may not notice much of a difference but for music these really shine. THX-265 complements the setup very well. Music sounds rich, silky, smooth. Listening to Michael Kiwanuka "Solid Ground" was such a moving experience I realized that I just will not be satisfied with anything else.
This is all without using the Atmos speaker features that these have. Instead I opted for the Alpha 8" directional in-ceiling speaker which are awesome and integrates very well into the mix.
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Rated 5 out of 5
Incredible
There is not a bad thing I can say about it except that I waited this long to buy it. I've tried to break it but have not succeeded yet. I've even played songs used in car stereo bass competitions at full volume and still sounds great. It works great for my home theater and daily (normal) music listening. I want to buy another but I would like to stay married more.
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Rated 5 out of 5
Very Happy
Excellent Sub. Exceeded expectations.
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