This should be the case. You can probably find performances that do localize well. My experience is that this is not generally true. I have played in large bands and orchestras (flute, BTW), and I now play in a recorder consort. Localization WITHIN the ensemble is not good. Music stands, risers, you name it. The whole acoustic environment is dirty. If the performers are lined up is a single line at the front of the stage, localization should be good. Not the normal arrangement for an acoustic group, though. Sorry for rambling, but.... Within an acoustic group, it is important that all of the musicians hear each other. This leads to a semi-circular seating arrangement. I did a church performance recently where our recorder consort was lined up across the stage. I was playing bass recorder at one end and I could not hear the soprano at the other end. The performance was terrible. Finally (I promise), It is getting increasingly difficult to find unamplified performances. Even the Met opera is now amplified.

>>Based on the above discussion, perhaps imaging is good to create the illusion of a live umaplified performance, even if it were not really that way. That's probably one of the reasons why so many folk like single driverspeakers that image so much better (beaming etc) when listening to small arrangements (like one singer and 4-5 instruments).

Certainly. As you said in your original post, creating an illusion is everything. I will take exception to the the statement that "we" like single driver speakers because of the imaging. IMO, the draw of single driver speakers is the lack of cross-over phasing problems in the 300-3000 Hz range where our ears are most sensitive to phasing. With the phase rotation in the cross-over region, our poor little brains become confused and don't properly reproduce the sound stage. This is why a single driver speaker is clearer and has more "life". IMO-YMMV

>>Keeping the room treatment constant, it makes intuitivie sense that speakers with higher directivity will image better. What do you & Wayne think?

Exactly. A highly directive speaker will image even in a poor room. Of course, nothing is free. The sweet spot may only be an inch wide.

Bob

Localization is different. Two point sources with uniform directivity can create an illusion of localization, and the apparent sound source can easily be made to sound as though it were coming from anywhere along the range between the two, and even outside them. But I don't think that's what people are referring to as "imaging." I think they're hearing the effects of complex dense interference. Just a hunch.

thnaks!
-akhilesh

Anything that causes multiple sound sources a half wavelength apart or more will cause interference. This can be two adjacent drivers in a multi-way speaker, in the overlap region where both drivers are playing. It can be two drivers in an array. It can be two loudspeakers, not in an array but placed where this occurs. It can be sound produced from a single driver coming from two edges of the cone. Or it can be from a single source and its reflection from a boundary or another outside object.

Where there is cancellation at a specific frequency, it causes a notch in response. It's easy to see on a response graph, having the tell-tale notched downward spike. Naturally, what most speaker manufacturers do is to strive to minimize these kinds of interactions. But another approach is sometimes taken, and that is to make the interactions so dense that they tend to average out. If there are lots of nulls spaced close together, that's called dense interference. If dense enough, it sort of averages the sound field.

http://www.prosoundweb.com/sr/tech_corner/

• Link!

"But if the room is good" - a BIG if. How do you make a typical room in your home not have early reflections except to make it anechoic, and that sound terrible. The only way to avoid early refections is with directivity.

About the sweet spot - if the directional device has a smooth coverage pattern it will have a larger sweet spot. To wit see my web site and the white paper.

Not all sound recordings are individually miked, but thats beside the point. On playback the image should be where the producer placed it, no matter what kind of music you listen to. he's the artistic director and he has the control - thats his job.

Yes there is a huge amount of disconnect in imaging discussions because people don't all see things the same way and they certainly don't use a consitent set of terminology. In the psychoacoustics world the terminology is well defined so I suggest using that. In pschoacoustics localization is imaging - same thing.

And the concept of "presnce" came up, which I call by the acoustician term of spatiousness (also well defined both subjectively and mathematically). People definately like spatiousness which is why we don't like anechoic chambers for listening even though they always have good imaging, and its one of the biggest factors in concert hall evaluation.

I totally disagree that all speakers can image well. Thats because the speaker itself has diffraction and diffraction smears the image. A diffraction-less speaker will always image well in an anechoic chamber - this I agree to.

So now comes the $60,000.00 question: How does one get good spatiousness and good imaging at the same time. Well rather than rewrite a long disertation I will direct you to the white paper on my web site which explains how this can be done.

My rooms have spationness because they are live, and they image well if you use my speakers - best of both worlds.