what type of subwoofer is good for ribbons

I am looking to buy a new set of speakers I am very interested in some magnepan ribbon speakers but they dont have enough bass i also heard that you need a special subwoofer for these in order for them to sound right what would make a good subwoofer for ribbon speakers
Duke (Audiokinesis) is too honorable to blow his own horn. However, nothing prevents me from doing it for him. His SWARM system is outstanding, if:

1) it's in your price range
2) you have the space to place 4 small-footprint subs
3) you can deal with the cabling for #2

I own his Planetarium Betas, of which the SWARM is an integral part. If, however, I were an owner of Maggies, Quads, or the notoriously bassy-shy M-L 'stat, I'd be all over these.
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try to find a panel subwoofer, such as the enigma or sound lab b2.

if you want to optimize coherence, a panel sub is the way to go.

unfortunately there are very few of them, and they may not extend low enough to satisfy some bass enthusiasts.

I don't know how I found it.......and can't read it. My eyes are watering so bad from this cold I can hardly see.

Somebody read it and summarize, please.
Also, please note in your answer how well your listening space conforms to the test space....mine? It couldn't.....I have an 8 sided asymmetric room with a vaulted ceiling.....a largish LR / DR in the California fashion.
> all the placement recommendations mentioned in the multisub paper on the Harman web site were very symmetrical not asymmetrical. Whether 2 subs or 4 subs, they are always in the same position on opposing walls.

The idea behind asymmetrical placement is to minimize standing waves by decreasing constructive interference i.e. each sub has a different interaction with its respective room boundary or boundaries, which smooths the overall response.

I have placed my four SWARM subs in many, many different locations, including a symmetrical setup. Trust me, you do not want to do this.