Open baffle speakers

Open baffle speakers have many virtues, very deep bass is NOT one of them because the front and back waves of the drivers are out of phase and bass frequencies wrap around the speaker and cancel each other.  One could use subwoofers or box woofers for the lower frequencies, but, depending on your taste and priorities, the bass without such augmentation can be good enough.  I've heard PureAudio Project open baffle speakers that, for my taste, have enough bass without augmentation.  The "small" version has twin 15" woofers, and the taller version has four 15" woofers.  I consider this brand's speakers to be among the very best for the money.  

I've heard some other open baffle speakers with quite large baffles and some with sides that go backwards to effectively extend the path length for front-back  interaction, but these tricks only reduce cancellation.  

My all time favorite open baffle speaker is really an open back speaker.  It had a Jensen M 10 field coil (13”) driver running full range with a high pass to a tweeter helping way on top.  This was a killer good speaker, but the $30 k for a matched pair of M 10 drivers makes it pretty expensive.

I never even considered that imaging would be a problem with open baffle speakers.  They do a good job when correctly placed, as do most other types of speakers.  In many respects, they are not much different from panel speakers, like Maggies, which also have a dipole radiation pattern that result in bass cancellation and substantial sound coming from the back.  If the back wave is sufficiently delayed in time reaching the listeners ear vis-a-vis the front wave, the ear/brain hears it as reverberation and not a confusing signal about the location of the original sound source.  Added reverb is generally not a bad thing and some people have spent a lot to generate additional reverb to supplement what is in the recording.

Bache,

Which commercial OB speaker did you hear that you found wanting in bass response?  What was it like otherwise?  I am surprised by how decent bass can be even with the dipole cancellation and the lack of reinforcement from bass reflex or sealed box loading.  This is not the case with all OB speakers I heard, but the good ones convince me that it is possible.

Spatial has some quite different views on OB.  They have a model which is open baffle/dipole for the woofers, and claims this is superior to conventional woofers because it reduces room interactions and modes, while it encloses the midrange and tweeter drivers so that the sound going backwards does not then reflect and add confusing information on sound location that would adversely affect imaging and muddle the sound.  The woofer claim is interesting because it is in keeping with what I have noticed with dipole panel speakers.  There is substantial cancellation at the sides that do reduce room interactions one does tend to get less boomy and uneven bass response.  I am less convince about not going OB with the midrange and tweeter because I tend to not mind the mid frequencies and highs from the back wave bouncing around the room adding to the reverberant field of sound, provided that the path length is 10 feet or more so the sound is perceived as an echo and will not be confused with the direct sound.

I like both the OB and the closed model of the Songer speaker.   The OB was a two way system using their field coil driver as a woofer/midrange coupled to an OB tweeter.  The closed box speaker did not have a tweeter so the field coil driver operated full range.  They both sounded very good, which is probably more of a testament to their field coil driver than to other aspects of their design.

There is another OB field coil speaker that I've heard made by Treehaus Audio.  They use huge slabs of wood cut so that the edges of the panel hold the outer bark of the tree.  The speaker can be stunningly beautiful.  One of the drivers is an old Klangfilm field coil driver that has been reconditioned.  I generally like the sound, though not as much as I do PureAudioProject and Songer Audio speakers, and they do look stunningly beautiful.    

I recently heard, and liked, the OB speakers from Cinnamon Audio (Portuguese).  It is a three-way with active amplification and DSP processing for only the bass driver.  The DSP corrects for room acoustics and applies the appropriate bass boost to account for back wave cancellation of the front wave.  This is a very nice dounding system.