Left, right, front, back, up and down

Yesterday's post touched on layers of depth and I am thankful so many of you chimed in with your opinions - I learned a lot from your comments. ARQuint writes: "As one of those writers who regularly refers to “layered depth”, I would love to ring in here. When I attend orchestra concerts, my preferred seats are on the ground floor, typically somewhere around Row I to R. This is where my wife and I sit for our Philadelphia Orchestra subscription, and what I ask for when I'm traveling and have a chance to take in a concert in another city. From seats like that, I can close my eyes and, although the “soundfield” is of course continuous, I can usually tell that the second violins are seated inside (further back towards the rear of the stage) the firsts; that the row of woodwinds with the clarinets and bassoons are behind the row with the flutes and oboes; that the brasses are behind the woodwinds; that the timpani and other percussion are along the back wall. This, to me, is different than generic “depth”, which may simply indicate a kind of acoustic spaciousness, or an indication of the recorded perspective (immediate, mid-hall, etc). I can hear layered depth on many choral and opera recordings as well, and even some pop recordings where it's entirely artificial but, nonetheless, a musically valid engineering decision." After reading these comments it's clearer to me how writers use this term "layered depth" to mean the physical separation, from front to back and from side to side of orchestra, choral or band members. Layered, or separated, in distinct "rows" or spaces. When our systems duplicate this layering effect or when we can "see" the positions of the orchestra players, our sense is that everything is just right with the imaging we've setup. I have always referred to this as "separation of instruments" but I rather like the visual I get from this layered depth. And, of course, we've been referring to this layering only in the horizontal plane when, in fact, any good imaging sound system has the added benefit of vertical size and - I am thinking - one could easily suggest these same layers exist in this up and down plane. Why loudspeaker systems reproduce soundstaging in the vertical plane is a bit of a mystery to me, but it certainly happens and it seems to be related to volume - although that really is dependent on the system. Another interesting comments was presented by Bassman23 and I found this of particular interest because he uses one of my all time favorite recordings to explain his point of view. "In terms of finding a way to (try to) create the image of a large hall in a small room, one need go no further than the excellent 1959 recording of Munch and the BSO performing Saint Saens' Symphony #3. Munch had the seats in the entire front half of the hall removed and the orchestra sections spread out over the full area for the purposes of this recording. The separation of the sections in the recording is remarkable – and the performance is one for the ages. By definition, the sound of this recording is surreal, as no live audience will ever hear this symphony with an orchestra arranged in space as this recording affords us. We hear the continuum of sound in this wonderful piece, as the waves approach the recording microphones naturally. However, modern recording techniques, with dozens of channels of discrete recordings being mixed together to achieve the finished product, will produce layers of sound if the recording engineer and record producer want to and have the skill to pull it off. Each individual sound can be treated separately to establish its own psychoacoustic space." I am thankful for all the great dialog on a very interesting subject. Our unofficial "technical editor" Soundminded had a number of great comments as well. Vertical imaging?