Check out the SVS 3000SB , or SVS 3000 micro depending on your needs and room size. They have a great user adjustable interface on the App which you can download for phone or tablet , the have a 45 day return ,they pay for shipping
and a 5 year transferrable warranty. The app alone is great I have the 3000SB-sealed box in true music the grand piano can ho down to around 27 hz which btw is below hearing more vibration low frequency ,30 hz is typically the limits of hearing actual musical tones , the sub can do below 20 hz great fior movies and electronic music ,and settings for movies , and music can be stored settings.