Not many modern stereo amps on the market offer adjustable bass management in a 2.1 system - such as the Meridian 251, Parasound, PS Audio, NAD Masters, Lyngdorf, and Yamaha network receivers.
Some brands have pre-out and sub out (without bass management), while others have a dual pre/sub out (you choose one or the other). Dealers inform me that this allows you to run your speakers at full range while running your sub at its own max crossover setting.
My Mac can go all the way to XI - Mac user since 1988 - Meridian owner since 1993.
M6, 218, 504, 506.2, AC12, SBT, Mac Mini Server, Amarra4, Loewe Bild7.55/Klang1 Sub/Sats, ATV4K.
In storage: Meridian 551, 555, A500, Director. VDH Teatrack, Mission Elegante e82, e81, e8c, B&W PV-1, Yamaha 5.1 Receiver, Yamaha DVD Player.