Principles of Multitrack Mixing: The Phantom Image
By Dave Moulton, with Alex Case and Peter Alhadeff
December 1992
The quirky natures of phantom images.
The view from 2005:
This was an early article (1992) I wrote for Recording Magazine (Home and Studio Recording then). Thinking about the quirky natures of phantom images and applying what I’ve found has led to many things in my professional career, including the principles behind Sausalito Audio Works’ Acoustic Lens Technology, a great deal about room design, and an immense amount about human hearing. Just so you know, I expanded this article into a section in my book, Total Recording. The Phantom Image
Stereo sound has proven to be a fabulously successful and effective way to present recorded music to listeners. The sense of spaciousness, realism and you-are-there ambience that come with a good stereo recording (as opposed to a monaural recording, consisting of a single signal) are powerful and exciting supports for good musical materials and performances.
The foundation for the stereo effect is the “phantom image,” a life-like apparent source of sound hovering in the space between the two loudspeakers of a stereophonic system. Creatively and effectively controlling the quality and placement of that image really improves the quality of a recording. One of the real benefits of this particular element of recording craft is that the listener doesn’t know
why the recording with well-crafted and convincing phantom images sound better, he or she simply
likes it more, finding the music more realistic and more enjoyable. It is one of the “magical” aspects of the craft.
The product of some rather elaborate mental operations by the auditory mechanism and brain, it comes in
two versions: monaural and stereo. The monaural (mono) version is the result of an identical signal sent to both loudspeakers. It is interesting that
we don’t sense the two loudspeakers as separate sources of energy that they are, but instead as only one imaginary source somewhere in
between the two real sources. Visualize two light bulbs in a dark room, situated in front of you, but off to the left and right. Imagine that when they are switched on, instead of seeing each of them, instead you only see one light bulb coming from a point between the two actual bulbs. That, friends, is the mono phantom image. Amazing!
The stereo phantom is quite similar to the monaural one, but is based on two signals that are not quite identical. Usually from
and in the same room.
, although it is possible to simulate it, as we will discuss later on.
