I test drove all the major contenders and pretenders.
best I’ve heard : ATC
Here’s the one I bought for my 2-channel “A” system. Highly recommended
ATC C1 Sub Mk2
Under that real wood veneer, there's a hand-built, 12-inch ATC bass driver and 3-inch ribbon voice-coil – which is hand pressed and assembled.
and you'll also get ATC’s standard six-year warranty