There are only a few rules to creating a worthwhile subwoofer, but the Pro 55 mk1 doesn't follow all of them.
In terms of looks – nondescript black box with little feet – it's right on the money.
Where sheer volume is concerned, it's up to snuff too: the MJ Acoustics will go louder than any sensible owner will require.
And as for impact, well, there's plenty of it. But it doesn't display much in the way of tonal subtlety, and the Pro 55 Mk1 can't control the trailing edge of bass notes as well as more capable rivals.
It ‘bottoms out' easily, too, meaning all that volume is best left unexplored