Speaker Imaging - Do you hear a line, or do you hear an arc??

First...THANKS Eric....for so darn many thought provoking threads that you have started!

I agree with the hemisphere/half bubble description.  No doubt that often the slightest change in speaker positioning will affect the overall sound...sometimes significantly. 


And, the straight line, arc, hemisphere soundstage is maybe most significantly influenced by what the recording engineer did with ambience, echo, reverb and delay....and then how your speakers and room interpret/project what he intended.

For a long time, I was obsessed with the soundstage...but realizing that perfection is probably an illusion in this area, once I had a good stage, I turned my attention to tone...especially piano, drums, horns and voices.

Interesting topic & something I once played around with quite extensively.

Oftentimes what we hear is an amalgam of various separately tracked & mixed instruments/voices, not necessarily recorded in the same acoustic space - so the soundstage can be somewhat artificial.

Soundstage depth (could be called an ’arc’) is ’correctly’ represented when the original recording & mastering contains it, speakers are fully time coherent & the room changes very little of what they produce ....In my experience, a very rare occurrence in domestic situations.

I have an accurately time and phase coherent setup in a heavily acoustically treated room. Many recordings do contain a holographic soundstage with considerable depth & most times instruments or voices are layered within that soundstage. Many other (2 channel) recordings sound artificial and ’flat’ to varying degrees and I guess this is just a true representation of the original source.

However; & this is the interesting bit... if I adjust time delay of one channel by varying degrees (DSP), say only 0.2ms (a tiny amount!) then the soundstage changes quite dramatically. Imaging is slightly less precise but the feeling of depth (& now width) increases very noticeably - almost as if in a larger more cavenous space. The ’arc’ becomes deeper & wider.

Playing around with increasing levels of time delay, even between different drivers creates all sorts of phasey ’soundstage’ effects, almost to the point where the whole room becomes an ill defined soundstage - impressively 3D but not natural. I once played part of a live album to a friend where I had deliberately delayed the entire left channel by 1.7ms and he couldn’t believe how we seemed to be inside the venue - diffuse but all around us (something I would never do other than as a demonstration of just what timing incoherence can do).

I concluded that prior to using DSP & room acoustics, much of the ’soundstage’ I used to believe existed was actually a function of the inherent inaccuracies created by the system/speakers & room. Often impressive but actually rather artificial.

With my system as it is now, I accept that what I hear is a truer representation of the original even if that means some recordings are no longer flattered by various phase and timing effects.

However; & this is the interesting bit... if I adjust time delay of one channel by varying degrees (DSP), say only 0.2ms (a tiny amount!) then the soundstage changes quite dramatically.

poppycock. Time delay will shift the image to one side.