Sealed Loudspeakers?

One reason I would never get rid of my gorgeous Avalon Ascent MKII's.Sealed 175 lb box,with two outboard 55lb crossovers.Very easy load(6 ohm),and amazing detail retrieval and timbres.Yes,I have added a big REL sub,as I have these speakers 8-9 feet out into room,and can use a drop of low end slam/depth,but the integration is flawless.
I truly believe the partnering electronics of the day was not up to this "classic" speakers performance match.Even the A/C power conditions are dramatically revealed with this wonderful design,which sounds a bit like a big Magico Mini.Every bit as revealing as the new(very nice,btw)Avalons,but better midbass,and lower midrange.It's the BIG external crossovers that proved to not have the best WAF,but the speakers(and crossovers,to me,anyway)are absolutely gorgeous in my tropical olivewood.
These appear once in a long while on the used market,and are a steal,at the usual asking price.Build quality is in the "heirloom" range.
Best!

You buy the New NSR Sonic Research with their patented
APL lens which is a sealed system that refocuses the soundwave for incredible tight Bass that is at least in the mid to low 20hz region cleanly for a speaker under $5k to do that and sound so cohesive on top is a breakthrough IMHO and many others at the shows including reviewers agreed.

Esp speakers are some of the best sounding speakers. The smaller models were some of the best at the RMAF.
As Glide3 said, they are sealed.

The entire range from Manger employs sealed enclosures.

the NSR Sonic Research D-3 was the best by far in any sealed enclosure I have ever heard,for a loudspeaker under 4ft tall to play cleanly below the range of any insrument which is a grand piano I believe around 27hz that is saying a lot, Hyperior,von SCH vr4mk2 are muddy in compare, with the patented APL system and this speaker is 93db efficient and disappears in the room.
On the east cost you can get a listen at http://hifidelityaudio.com I have mine on order this is the best loudspeaker I have ever heard in the $5k range
and I have heard a lot.