Phono Stage upgrade to complement Dohmann Helix One Mk 2

I've read some comments on a subwoofer thread about how the user preferred Class A/AB amplifier for the subwoofers, as the class D truncated notes too quickly, and the like.  Consquently, currently, I'm leaning towrards favoring passive subwoofers driven by a Class A or AB amplifier(s) (which I already have).  I think I'll give Duke a call at Audiokinesis sometime soon to see what he has to offer, as I think the "swarm" can be purchased with only passive subwoofers. . . but I'll still have address LPF, HPF, etc. with that option.   

@drbond , The best bass I have heard comes from monster class A amps with exceedingly low output impedance, vanishingly low. I agree that passive subwoofers are the way to go. The problem is getting them, ones that fit your spec. AudioKinesis swarms do have outboard electronics and Duke might sell you a set without the electronics. The swarm system is a great, high value subwoofer array for people with small to intermediate size rooms and systems in the $20,000 or so price range. To play around and get used to subs and not spend to much money doing it I suppose they are fine. In the end they are not up to the quality of the rest of your system and even with four 10" woofers they are really not enough for your rather large room. My current system uses four 12" subs in a room 16 feet wide. There is no back wall as it is an open concept house. The room was designed to avoid standing waves. The system I am working on now will include eight 12" drivers in 4 enclosures. 

The best way to get passive sub is to make them. There are great kits available at Parts Express with SOTA drivers. They are as good as 90% of the commercial subs on the market and very easy to build. The only fly in the ointment is putting a fine finish on them. You can give them to a Piano restorer and they can put an excellent black finish on them. Many people cover them in equipment carpet. 

@lewm, not at all. I can AB straight analog with full bore processing by pressing a button. I have to assume you know what you are listening to and in that context it is a no brainer.  I know you don't think so which makes it more fun. 

@mijostyn 

I spoke with Duke LeJeune at Audiokinesis, and he agreed with you that the "Swarm" would not suffice in my room, due to its size.  He mentioned that he could make some custom subwoofers with either 12" drivers or possibly with s 10" drivers per box.  His set up would have the potential to be sealed, vented, or double vented.  He also mentioned that his subwoofers are passive, but he recommends a amplifier that can be set to a 4th or 5th order LPF.  Presently, I'm going to investigate and pursue this option for the next few weeks. 

Ask Duke if he can do two 12” drivers per enclosure in a balanced force arrangement. Sealed enclosures only please. 

If you really wanna go crazy, and if you have a big room, ask Sound Labs about their B1 ESL subwoofer.