Did Toole/Olive/Harman measure any omni’s?
No, but there's this guy named Amir who
measured and evaluated an omni on that crazy ASR forum.
It was just an inexpensive little desktop thing, and its calculated Preference Rating was the absolute WORST: -0.1. That's a NEGATIVE score! I didn't know that was even possible.
Now this isn't what we'd call a "serious" speaker, but despite the unbelievably bad Preference Rating, Amir liked it enough to recommend it!
How might a "serious" omnidirectional speaker have scored, and would Amir have recommended it? I hope we find out some day.
Omni’s, I have heard MBLs,Audio Physiks at Munich, Beolab 90 has an omni mode which I found a little disorientating, Shahinians of various hues, although they aren’t true omni’s , are they just toys or do they have any merit.
At the risk of oversimplifying, the primary benefit of a good omni is that it generates an exceptionally well-energized and spectrally correct reverberant field, which can do an excellent job of conveying natural-sounding timbre and effectively presenting the reverberation cues on the recording (which in turn convey a sense of immersion).
The primary drawback of omnis is that they tend to put a lot of energy into the early reflections, which are the ones most likely to degrade imaging precision and clarity.
So, omnis generally sound best positioned well away from the walls in a large room, which is how MBL likes to show their big Radialstrahlers. This pushes those early reflections far enough back in time that they are no longer detrimental. In smaller (inadequately treated) rooms, ime there is an audible "small room signature" with omnis which can be distracting. But well set-up in a nice big room, they can be magnificent.
In my opinion the improvement from "small room - yuck" to "big room - OMG!!" is not adequately explained by simply adding a few milliseconds more time delay to the reflections. Instead, here is what I think is happening:
In the small room, the relative abundance of early reflected energy tells the ear/brain system "you're listening in a small room".
But in the big room, the relative absence of early reflected energy (especially in comparison to the abundance of later-arriving reflected energy) does not convey a strong "small room signature", and at the same time all those late reflections are delivering the ambience clues on the recording from all around, so the recording venue cues dominate. We go from primarily hearing the playback room to primarily hearing the recording venue, and imo that difference is huge.
