Omnidirectional speakers. The future?

Opalchip, interesting points you bring up. I can't help but have a question come to mind: When you listen to a grand piano in a recital hall, the vast majority of the sound power that reaches your ears from the piano is reverberant energy, not direct energy. Would you consider this reverberant energy (which cannot possibly be time and phase coherent with the original signal) to also be "distortion"?

You see, the ear treats sounds arriving at different times in different ways. Different cues are extracted from reflections than are extracted from the first-arrival sounds. I believe the correct approach is to see them as two separate events, and to try to get them both right.

Twilo, I didn't hear the Hsu bipolar setup, but believe your description. However, note that the back-to-back speaker pair will probably have a deep notch in the response centered on the frequency where the path length difference from the two sets of drivers to the listening position is equal to 1/2 wavelength. Assuming the back-to-back speakers were each 8" wide and 6" deep the on-axis path length difference is 6 + 6 + (8/2) = 16 inches, so at approximately 420 Hz you'd have severe cancellation, along with partial cancellation at nearby frequencies. So back-to-back speakers may not be the ideal solution.

If I recall correctly, Mirage used a single bass driver on the front of a wide cabinet, and a rear-firing midrange and tweeter on the back of the cabinet crossed over higher than that 1/2 wavelength notch frequency. Definitive Technology patented a technique for using side-firing woofers along with forward and rearward facing mid/tweet arrays, once again to avoid that 1/2 wavelength cancellation notch.

The microphone "samples" one point of a planar wavefront generated during the performance. A planar loudspeaker recreates the planar wavefront, and what happens after that, regardless of what kind of loudspeaker is used, is at the mercy of room acoustics.

Can you give some examples of point sources? Every instrument I can think of, with the exception of a human vocalist, has a sounding board larger than the typical cone driver.

Hi AudioKinesis - IMHO the reverberant energy in a hall is either a fortunate or unfortunate attribute of that hall - depending on one's tastes and location. I would call it distortion, as compared to the piano in an anechoic chamber. Except that, to get philosophical about it, certain genres, forms, and specific pieces of music were developed/composed with certain assumptions about the acoustical properties of the places or media where they were likely to be heard - especially with regards to classical music, e.g. Russian church choral music wouldn't sound right in a jazz club.

But my point is that the best a speaker can do is re-create what you would have heard at the point where you were sitting - and a microphone has ALREADY picked up all those reflections, time-delayed, and out-of-phase sounds.

As far as the ear's diaphragm is concerned, there are never "sounds arriving at different times in different ways" - there is only one complex waveform which already IS the net sum of all those primary and secondary elements hitting you at any point in time. (That's why there is only one groove necessary in a record). This is what the microphone records, and is all that needs to be re-amplified. Adding omni-directional characteristics to speakers is simply like changing the acoustics of the hall that the piano was recorded in. Some will like it, others won't - but it's not what was there in the first place.

I'm not a purist in the sense of maintaining the original if something else is more pleasing or fun, but personally, I'd rather have a Yamaha DSP that gives all sorts of acoustic playback options - including the option of turning it off. And I'm a big fan of the DBX 5bx dynamic range expander (which actually DOES restore the signal to more like the original.)

I just think that if you want to alter the signal that's on that CD or LP, having your speakers bouncing sound off the walls and ceiling is really not the best way do it.

Opalchip, I agree with most of what you had to say about hearing what is on the recording unedited by the design of certain speakers types. And it was well said. BUT a Yamaha DSP or a DBX5bx? Boy, did you lose some ground there! :-)

Just give me my hair shirt thank you......

Opalchip,
Come listen to my Shahinian Diapasons. Then you might change your mind. I think of sound like light. Direct light in the eyes is irritating. Reflected and diffused light is pleasant. The word distortion does not come to mind when listening to the Shahinians. The word real does.

If reflections are distortion then you must think the ideal listening room is an anechoic chamber. I can assure you that it is not. The most experienced acoustic engineers use both diffusion and absorption in room design.