It’s clear that you have to adapt your expectations to the price. This is a low end of the line subwoofer and as long as you stay in the first half of the amplification range, you get kind of a decent bass, the louder it gets, and at least I get the feeling that the sound gets mushier.
My use case is a multifunctional studio in the penthouse of our house. I use it for music and movies. It complements my two loudspeakers which lack the deep side of the bass spectrum. And honestly, the sound range is now more complete and especially when I don’t turn up too loud, there’s now this pleasing deep bass my installation lacked before. But the bass is not of very good quality, it’s just ok, but no comparison with a nice high end hifi sound.
As I didn’t want to spend more, I arranged myself with the compromise. I think that it’s useful for rooms up to 50 square meters.