Open Baffle loudspeakers.

i built a pair of the wild burro audio labs using their full range betsy driver. cost under 150 dollars and was a fun project to get into full range, single driver, no crossover speakers. very effecient also and i drive them with a 25 watt fatman hybrid integrated. sound quality is pretty good. but like with most audio there is more to the story. read about open baffle on wickipedia and many other sites on dyi forums. you can get real involved in this with fostex and tannoy drivers which are expensive compared to how i went. also type into "pictures of open baffle speakers" for lots of creative ways some people have built theirs. some people are into open baffle because they do get lots of things right in the midrange and soundstage image. i enjoy mine and may build another pair some day. good luck with this. btw there are companies like hawthorne audio and others that will make some very nice speakers for you if you don't want to build your own.

There is a speaker designer in eastern Iowa that is designing some open-baffle speakers that sound promising while being inexpensive. He is talking about having it in kit form and also in finished trim. The guy's name is Jack Caldwell and he has a company named Holistic Audio Arts. Do a search on the name and it will pull up his info.
Best of luck.

There are numerous production speakers that use little or no baffle. Here is a partial list:
Vandersteen 1C, 2Ce, 3a
Most electrostatics
Most magnetic ribbon speakers
MBL Radialstradters
Walsh models from Ohm, HHR, Decware, & Audio Physics

...and many more.

I have heard and/or owned a handful of the speakers listed above, and I have always preferred the sound of baffle-less speakers to other designs, especially in the lower price categories. When the budget is bigger, more inert cabinets that pricier speakers have can narrow the gap between baffle and baffle-less speakers considerably, IMHO.

The problem with open baffle speakers is the bass. The rear energy can wrap around and null the front energy. To overcome this, you need either wide baffles or U or H frames. Still, many OB speakers use 12 or 15", high Q drivers. Too high and they get sloppy. (ie. Carver Amazings)

Seems to be more popular among the DIY'ers and kit builders (GR Research) than commercially, not just because a decent box can be a PITA to build. The size and placement (at least 3' from back wall) are factors. Part of the reason for OB resurgence is the availability of subwoofers. Personally, I wouldn't tackle an OB project without DSP because what works for 50Hz might not work for 200Hz.

A popular choice of driver, including coax, is Eminence (particularly Alphas) but AE Speakers' dipole series look good.

As with any kind of dipole, what you lose in vocal "focus" you gain elsewhere.

The trick to OB's as Ngjockey said is DSP!!

I started out with a set of stock Hawthorne's...really good...kinda felt like I had my Maggies back but without that super small sweet spot!!

Then I bi-amped them with a Behringer DCX2496 and added subs...improved greatly!!

Next step...removed the Behringer for a DEQX...best move I have ever made in my audio swapping days...that thing is amazing...I'll never be without one!!! So simple with such great results, I just don't understand why people aren't eating them up!!

You can take a good speaker and make it really good or a really good speaker and make it great!!!

And mine are mounted on a 18" x 28" board 2' from the back wall with a slight tilt up...love it!! You don't have to be fancy but you now have the option to if you want...

Anyhoo...I betcha heard this before...once you go to an OB, you'll never go back to a box!! You'll always hear a box!!

My 2 cents :)

Nola speakers are open baffle in the mids and highs with a sealed box on the woofer only. Great sounding speakers!

I have Salk SoundScapes that have an open baffle midrange. Box speakers don’t reproduce the liveliness that is often heard on the musical stage. Open baffle and panel speakers are attempt to solve the problem. The bass issue mentioned previously is something that needs to be addressed by the speaker designer.

Advantages:

1. Liveliness is added(restored?) to the music
2. Freedom from box resonances

Disadvantages:

1. The image is larger than life
2. Bass frequencies are a difficult problem to address
3. There is the back wave of music coming out behind the speaker that reflects off of the wall. These reflections need to be managed.

FWIW, Dennis Murphy solved the image problem by putting the open baffle midrange in an partially fiber filled open backed box.

Bob

One more advantage of open baffle speaker is that the image can be deeper and wider. One more disadvantage is that the added ambiance makes the image less clear and vocals less distinct. Proponents of open baffles say that the extra clarity is from artificial recording studios and opponents of open baffles say that the ambiance generated by open baffle speakers is artificial.

Bob

You can add Emerald Physics to the list. I have the CS2.3's in a tri-amped configuration and they are just amazing. The 2.3's have two 15" woofers per side to deal with the OB bass issue. DSP/active crossovers are the way to go. My DEQX will be here in two weeks. Can't wait!

Sideways: Any chance that you're using the upgrade transformer balanced output boards on the DEQX?

Good news Cdente...you'll love it!!!

As for me...I'm cheap LOL!!! I found a great buy on a 2.6P...like I said...best move I've ever made in my audio career :)

To you Ngjockey...no...stock unit using stock rca outputs!!

I'm sure I could go balls out but in all honesty, I don't feel the need too...the experience I am having\getting is fantastic in it's own right...I know it can be improved but I'm enjoying it that much that I don't feel the need to tinker at the moment!!!

Maybe some day I'll spring and go higher up the food chain...my buddy has an Express and a 3...he's waiting for the 4...he's a dedicated 110% DEQX man!!! I am too but have to save the pennies first ROFL!!!

Funny thing is, when you have a chance to experience the DEQX first hand, you kinda lose interest in the For Sale Ads after that...oops!!!

I attached an exciter to a 2x2 foot, 1" thick piece of solid, pink insulation.  Using the positioning '2/5  3/5 rule', I heard a perfectly clear, quick and well balanced sound:  well balanced for a certain upper level of frequencies.  Having not tried it, I'd assume a much larger piece would offer more bass, but uncontrolled bass....blurry, without texture.  I guess you'd just have to use traditional boxes to get good mid bass down to bass, but still, wouldn't it be worth it for the air and clarity?  Acoustic guitars, the shimmer of drums and the air in 'wind' instruments sounds amazingly real.  Has anyone experimented with the larger exciters?  What other baffle mediums have you used?

+1 @grannyring on Nola.  In my experience, open-baffle cone drivers are a great compromise between completely closed-box speakers and planar or electrostatic designs.  Done well, I find open-baffle dynamic cone speakers in general to be more open sounding than box speakers but with greater tonal density and "oompf" than flat panel designs along with fewer bass production and integration issues.  Nola in particular has got me rethinking what my own end-game speakers may end up being precisely because of this issue.  Hearing their Grand Reference towers at a show in NYC years ago continues to be the single most impressive audio reproduction experience I've had. 

Spatial is another brand not mentioned previously that embraces an open-baffle architecture. 

I have a pair of Spatial Audio X1 Turbos.  They're wonderful, with tight, solid bass and a good presentation all the way up through the high end.

Then, last Christmas, I decided that I deserved a pair of Spatial X2s.  Even more wonderful, with fabulous bass down to 18Hz, and an air motion transformer handling the high end.  They image like crazy, and are utterly non fatiguing.  I listen to them for hours at a time.

I put the old Spatials in my system in my finished basement apartment.  They, and I, like their new home.