Quote from: voltronic on July 19, 2013, 12:53:54 AM
Hmm, I guess I need to go study the SZ paper again. I was under the assumption that ORTF would actually pickup less room sound becuase while the mic angle is widest of the 3 arrangements, its SRA is narrowest. This is the part of the SZ paper that took me the longest to wrap my head around, and maybe I still don't quite get it. 
It's not intuitive. I still get confused about it and have to think it though at times, but this is how I think about a basic dichotomy going on with mic configurations- there are two separate primary aspects: The
combined polar pattern of the mic pair and the stereo playback imaging it produces. The Stereo Zoom addresses the playback imaging part directly, what it doesn't address directly but one of the important things which changes when selecting between different Stereo Zoom configurations with equivalent SRAs, is the combined directional sensitivity of the two microphone patterns which effects sound arriving from outside the SRA. It's not the polar plot for a single mic, but the combination of two in that specific arrangement, covering the region where the two patterns overlap enough to produce stereo imaging (the stereo zoom region), but also including large areas of sensitivity outside of the SRA 'frame' which crops the playback image window between speakers. And it's that region where much of the sonic reflections, audience reaction, cooks in the kitchen, and reverberant information is coming from.
There are also other aspects that change when switching between different configurations which produce same SRA, such as the specifics of the distribution of individual sound sources within the SRA window- whether they are spaced evenly across the playback window in the same relationship as they were at the recording session or clumped towards either speaker towards the edges, but that is of secondary importance to how the combined polar pattern effects the ambient pickup of sound arriving from outside to the SRA window.