Rythmik hasn't seemed willing to play the review game lately. That, and with their marketing about the magical servo tech has earned them some questions about whether their gear really stands up. That said, users frequently report satisfaction and good experiences. But are the servos really anything special?
data-bass.com
Shady reviewed the Monolith 15" here:
At last! It's here! Our review of Monoprice's monster subwoofer, the Monolith 15" THX Ultra! This 130 lb. beast might look like it's all muscle, but there's at least as much brains as there is brawn.
www.audioholics.com
By all accounts, this is a monster sub and worth it. The THX rating is a rigorous standard that pretty much guarantees very good performance within it's parameters. A good comparison with this is the Outlaw Ultra X-13, also reviewed by Shady here:
Outlaw Audio recently released their new Ultra-X13: a 1,000 watt, ported beast of a subwoofer that uses a long-throw 13" driver and has a THX 'Ultra' certification. Read on to find out more.
www.audioholics.com
If I recall correctly, this Sub earned the THX rating as a single sub. Uncertain about the Monolith, but many of these rated subs earn that rating in pairs as I understand it.
I'd keep the x-13s in your mind, especially if they go on holiday sale like they usually do ($1000, shipped).
Both the Monolith series of Subs, and the X-13 are designed by Claridy Audio for Monoprice and Outlaw respectively. Claridy does nice work.
Regardless, to your original question, I would lean towards the Monolith.
