The Diorama Effect in Stereo Imaging and Soundstaging

First observed as a visual artifact in 3-D cinematography, does the “diorama effect” also occurs in the world of audio?


By: Ringo Bones


Everyone might have very well underestimated the influence of James Cameron’s Avatar. Not only does it help sell a new generation of wide and flat 3-D capable video displays for the home, but also made everyone yet again notice what’s good and what needed improving about 3-D cinematography. Many 3-D cinematography enthusiasts point the blame at the “diorama effect” even though this visual artifact also occurs in prism-equipped binoculars, but does it have an audio equivalent that could give every hi-fi enthusiast a renewed bout with “audiophilia nervosa”?

Having been fortunate enough to acquire the funds to fully indulge myself in the experimenting and upgrading side of purist two-channel – i.e. stereo – audio during the past twenty-one years, a eureka moment finally dawned on me as I watched the 3-D version of Avatar. Especially the scenes of “near contemporary” military hardware and lush tropical fauna where every visual artifact that is incongruent with how our eyes see real life sticks out like a proverbial sore thumb. Which had me realize that two-channel stereo – like 3-D cinematography – has its very own version of the diorama effect that’s seldom discussed in the wider world of audiophile journalism.

Compared to how we hear an unamplified musical performance in nature, many purist two-channel stereo systems that I’ve encountered – especially those with transistor-based amplification – tend to produce a somewhat artificially structured soundstage. A soundstage that has a narrow listening area with imaging that locates recorded musical instruments and voices with a precision that never occurs in a natural unamplified musical performance. In short, an overwhelming number of two-channel stereo systems have the propensity to create an artificially detailed soundstage that sounds too good to pass muster as natural. The audio equivalent of the diorama effect?

Probably due to the way lithe budget integrated transistor amplifiers that became popular during the late 1980s tend to project acoustic images in a somewhat cubist manner, mainly due to the brightness their added switching distortion creates. Good sounding as these units are, audio enthusiasts who can afford experimented with tube based amplification – especially single-ended triode types – to minimize the cardboard cut-out like imaging producing the acoustic equivalent of the diorama effect of their audio system’s imaging and soundstaging capabilities.

Low power can be an issue, especially if you find the 300B single-ended triodes too dull and the even lower powered 2A3 has difficulty driving the speakers you currently have. But these designs are as good at individual precision images as any high-caliber transistor effort, though without that sharp-edge cut-out effect – i.e. the audio equivalent of that 3-D cinematography imaging artifact called the diorama effect. With good single-ended triode designs, you can as if walk around those individual sonic images. An audio refinement to make your stereo system’s imaging and soundstaging capabilities more akin to real life.