Omnidirectional speakers. The future?

The "Walsh Series" of Ohm loudspeakers are not omni-directional in any aspect of operation. This is specifically covered on their website. They simply present a diffuse presentation, which may confuse some folks into thinking that they are omni's due to the lack of focus. Sean
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The amount of misleading "science" thrown around by "audiophiles" sometimes drives me nuts!

Some people obviously like the "sound" of omni-directional speakers - but what they are liking is a form of increased phase and time alignment distortion from having the original signal bouncing around the listening area. There used to be all sorts of electronic "spatializers", or "spacial enhancement" boxes in the 70's and 80's that did exactly what omni's do - introduce controlled phase and time distortion. Why? - because some people found it pleasant or fun. "Distortion", which is simply a deviation from the original source's output, isn't necessarily unpleasant but let's be real about what it is.

1. Your ears are not able to discern the broad "shape" of the "front" of a soundwave. A change in the air pressure in your ear canal moves your eardrum either in or out, which in turn vibrates some bones, which then vibrate fluid in your inner ear, and finally - at the back of your inner ear that is converted to an electrical impulse. In addition, the "cleanest" wave you can incite will come from a smooth "point" source.

2. The idea that somehow bouncing recorded output around at random is more accurate than directing back, from a "point source", what stereo microphones have already picked up is nonsense and/or marketing hype. You only have two ears - and they do exactly the same thing as microphones. You don't need 6 or 8 ears to receive spatial information. The most accurate thing a speaker can do is create in reverse EXACTLY what occured at the diaphragm of the microphone. It's extremely delicate information, and the more it bounces around the room, the more of it is lost, period! Of course it's not perfect reproduction - everything ELSE a speaker does may sound good to some people and bad to others, but it's "distortion". The spatial information of the original sounds' environment is ALREADY IN THE SIGNAL - you don't need to somehow alter or re-recreate it to make it more "real".

3. I have owned many types and brands of speakers, sometimes 8 or 10 pairs at once, and have a very nice A/B testing set-up where I can swap from one pair to another using only a foot switch. I personally prefer minimum baffle speakers***. But for example, even in A/B testing the Dahlquist DQ20i (minimum baffle) against the Alon V (which is an extremely similar design but has a 90% OPEN baffle mid and tweet) it is becomes apparent how much distortion the rear waves from the Alon's sets up. By itself, it sounds "open" and "spacious" - in A/B it sounds open, spacious, and MUDDY!

*** Of course, minimum baffle design is also a trade-off of where you like your distortion, too. Instead of output reflecting immediately off the baffle, there'll be more "escaping" to reflect from surrounding walls, etc. Apparently, my ears prefer that.

Some early Ohm/Walsh's I believe, were omni. They decided to un-omni the consumer line (starting with the Ohm/Walsh 2, I think) to make room placement easier simply by placing a baffle inside the mesh canister which absorbed/deflected the "rear" output from the Walsh cone.

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.