Fictional electronic instrument of the future in Chapter 17 of Foundation and Empire by Isaac Asimov (1952). It produces holographic visual effects as well as musical ones, and is difficult to play well.
It was the inspiration for another fictional instrument, Futurama's holophonor.
Foundation and Empire was a "fix-up" novel, patched together by the author from previous works, so the Visi-Sonor first appeared in print in the short story "The Mule (Part I)" in the November 1945 issue of Astounding Science Fiction:
Mis shrugged, and turned again to Magnifico. He unwrapped the package, "Know what this is, boy?"
Magnifico fairly hurled himself out of his seat and caught the multi-keyed instrument. He fingered the myriad knobby contacts and threw a sudden back somersault of joy, to the imminent destruction of the nearby furniture.
He croaked, "A Visi-Sonor — and of a make to distil joy out of a dead man’s heart." His long fingers caressed softly and slowly, pressing lightly on contacts with a rippling motion, resting momentarily on one key then another — and in the air before them there was a soft glowing rosiness, just inside the range of vision.
Ebling Mis said, "All right, boy, you said you could pound on one of those gadgets, and there's your chance. You’d better tune it, though. It’s out of a museum." Then, in an aside to Bayta, “Near as I can make it, no one on the Foundation can make it talk right."
He leaned closer and said quickly, "The clown won't talk without you. Will you help?"
"Good!" he said. "His state of fear is almost fixed, and I doubt that his mental strength would possibly stand a psychic probe. If I’m to get anything out of him otherwise, he’s got to feel absolutely at ease. You understand?”
She nodded again.
“This Visi-Sonor is the first step in the process. He says he can play it; and his reaction now makes it pretty certain that it’s one of the great joys of his life. So whether the playing is good or bad, be interested and appreciative. Then exhibit friendliness and confidence in me. Above all, follow my lead in everything.” There was a swift glance at Magnifico, huddled in a corner of the sofa, making rapid adjustments in the interior of the instrument. He was completely absorbed.
Mis said in a conversational tone to Bayta, “Ever hear a Visi-Sonor ?”
“Once,” said Bayta, equally casually, “at a concert of rare instruments. I wasn’t impressed.”
“Well, I doubt that you came across good playing. There are very few really good players. It’s not so much that it requires physical co-ordination — a multi-bank piano requires more, for instance — as a certain type of free-wheeling mentality.” In a lower voice, “That’s why our living skeleton there might be better than we think. More often than not, good players are idiots otherwise. It’s one of those queer setups that makes psychology interesting.”
He added, in a patent effort to manufacture light conversation. “You know how the beblistered thing works? I looked it up for this purpose, and all I’ve made out so far is that its radiations stimulate the optic center of the brain directly, without ever touching the optic nerve. It’s actually the utilization of a sense never met with in ordinary nature. Remarkable, when you -come to think of it. What you hear is all right. That’s ordinary. Eardrum, cochlea, all that. But — Shh He’s ready. Will you kick that switch. It works better in the dark."
In the darkness, Magnifico was a mere blob, Ebling Mis a heavy-breathing mass. Bayta found herself straining her eyes anxiously, and at first with no effect. There was a thin, reedy quaver in the air, that wavered raggedly up the scale. It hovered, dropped and caught itself, gained in body, and swooped into a booming crash that had the effect of a thunderous split in a veiling curtain.
A little globe of pulsing color grew in rhythmic spurts and burst in midair into formless gouts that swirled high and came down as curving streamers in interlacing patterns. They coalesced into little spheres, no two alike in color — and Bayta began discovering things.
She noticed that closing her eyes made the color pattern all the clearer; that each little movement of color had its own little pattern of sound; that she could not identify the colors; and, lastly, that the the globes were not globes but little figures.
Little figures ; little shifting flames, that danced and flickered in their myriads; that dropped out of sight and returned from nowhere; that whipped about one another and coalesced then into a new color.
Incongruously, Bayta thought of the little blobs of color that come at night when you close your eyelids till they hurt, and stare patiently. There was the old familiar effect of the marching polka dots of shifting color, of the contracting concentric circles, of the shapeless masses that quiver momentarily. All that, larger, multivaried— and each little dot of color a tiny figure.
They darted at her in pairs, and she lifted her hands with a sudden gasp, but they tumbled and for an instant she was the center of a brilliant snowstorm, while cold light slipped off her shoulders and down her arm is a luminous ski-slide, shooting off her stiff fingers and meeting slowly in a shining midair focus. Beneath it all, the sound of a hundred instruments flowed in liquid streams until she could not tell it from the light.
She wondered if Ebling Mis were seeing the same thing, and if not, what he did see. The wonder passed, and then —
She was watching again. The little figures — were they little figures? little tiny women with burning hair that turned and bent too quickly for the mind to focus? — seized one another in star-shaped groups that turned — and the music was faint laughter — girl's laughter that began inside the ear.
The stars drew together, sparked toward one another, grew slowly into structure — and from below, a palace shot upward in rapid evolution. Each brick a tiny color, each color a tiny spark, each spark a stabbing light that shifted patterns and led the eye skyward to twenty jeweled minarets.
A glittering carpet shot out and about, whirling, spinning an insubstantial web that engulfed all space, and from it luminous shoots stabbed upward and branched into trees that sang with a music all their own.
Bayta sat inclosed in it. The music welled about her in rapid, lyrical flights. She reached out to touch a fragile tree and blossoming spicules floated downwards and faded, each with its clear, tiny tinkle.
The music crashed in twenty cymbals, and before her an area flamed up in a spout and cascaded down invisible steps into Bayta's lap, where it spilled over and flowed in rapid current, raising the fiery sparkle to her waist, while across her lap was a rainbow bridge and upon it the little figures —
A place, and a garden, and tiny men and women on a bridge, stretching out as far as she could see, swimming through the stately swells of stringed music converging in upon her —
And then — there seemed a frightened pause, a hesitant, indrawn motion, a swift collapse. The colors fled, spun into a globe that shrank, and rose, and disappeared.
And it was merely dark again.
A heavy foot scratched for the pedal, reached it, and the light flooded in; the flat light of a prosy sun. Bayta blinked until the tears came, as though for the longing of what was gone. Ebling Mis was a podgy inertness with his eyes still round and his mouth still open.
Only Magnifico himself was alive, and he fondled his Visi-Sonor in a crooning ecstasy.
"My lady," he gasped, "it is indeed of an effect the most magical. It is of balance and response almost beyond hope in its delicacy and stability. On this, it would seem I could work wonders. How liked you my composition, my lady ?"
"Was it yours ?" breathed Bayta. "Your own?"
At her awe, his thin face turned a glowing red to the tip of his mighty nose. "My very own, my lady. The Mule liked it not, but often and often I have played it for my own amusement. It was once, in my youth, that I saw the palace — a gigantic place of jeweled riches that I saw from a distance at a time of high carnival. There were people of a splendor undreamed of — and magnificence more than ever I saw afterwards, even in the Mule’s service. It is but a poor makeshift I have created, but my mind’s poverty precludes more. I call it, 'The Memory of Heaven.'"
The visi-sonor also appears in Asimov's short story "Tyrann" published in the January 1951 issue of Galaxy Science Fiction magazine, but the musical aspect of the instrument is downplayed somewhat. In this story it is the invention of Gillbret, who demonstrates it for protagonist Biron Farrill:
Biron looked it over slowly. "And you build gadgets here? What kind of gadgets?"
"Well, special sounding devices to spy out the Tyranni spy-beams, in a brand-new way. Nothing they can detect. That's how I found out about you, when the first word came through from Aratap. And I have other amusing trinkets. My visi-sonor, for instance. Do you like music?"
"•Good. I invented an instrument, only I don't know if you can properly call it music." A shelf of book-films slid out and aside at a touch. "This is not really much of a hiding-place, but nobody takes me seriously, so they don't look. Amusing, don't you think? But I forget, you're the unamused one."
It was a clumsy, boxlike affair, with that singular lack of gloss and polish that marks the home-made object. One side of it was studded with little gleaming knobs. He put it down with that side upward.
"It isn't pretty," Gillbret said, "but who in Time cares? Put the lights out. No, no! No switches or contacts. Just wish the lights were out. Wish hard! Decide you want them out."
And the lights dimmed with the exception of the faint pearly luster of the ceiling that made them two ghostly faces in the dark. Gillbret laughed lightly at Biron's exclamation.
"Just one of the tricks of my visi-sonor. It's keyed to the mind just as personal message capsules are. Do you know what I mean?"
"No, I don't, if you want a plain answer."
"Well," Gillbret said, "look at it this way. The electric field of your brain cells sets up an induced one in the instrument. Mathematically, it's fairly simple, but as far as I know, no one has ever jammed all the necessary circuits into a box this size before. Usually, it takes a five-story generating plant to do it. It works the other way, too. I can close circuits here and impress them directly upon your brain, so that you'll see and hear without any intervention of eyes and ears. Watch!"
There was nothing to watch at first, and then something fuzzy scratched faintly at the corner of Biron's eyes. It became a faint blue-violet ball hovering in mid-air. It followed him as he turned away, remained unchanged when he closed his eyes. And a clear, musical tone accompanied it, was part of it, was it.
It was growing and expanding and Biron became disturbingly aware that it existed inside his skull. It wasn't really a color, but rather a colored sound, though without noise. It was tactile, yet without feeling.
It spun and took on an iridescence while the musical tone rose in pitch till it hovered above him like falling silk. Then it exploded so that gouts of color splattered at him in touches that burnt momentarily and left no pain.
Bubbles of rain-drenched green rose again with a quiet, soft moaning. Biron thrust at them in con- fusion and became aware that he could not see his hands or feel them move. There was nothing, only the little bubbles filling his mind to the exclusion of all else.
He cried out soundlessly and the fantasy ceased. Gillbret was standing before him once again in a lighted room, laughing. Biron felt an acute dizziness and wiped shakily at a chilled, moist forehead. He sat down abruptly.
"What happened?" he demanded, in as stiff a tone as he could manage.
Gillbret said, "I don't know. I stayed out of it. You don't understand? It was something your brain had lacked previous experience with. Your brain Was sensing directly -and it had no method of interpretation for such a phenom- enon. So as long as you concentrated on the sensation, your brain could only attempt, futilely, to force the effect into the old, familiar pathways. It attempts separately and simultaneously to interpret it as sight and sound and touch. Were you conscious of an odor, by the way? Sometimes it seemed to me that I smelled the stuff. With dogs I imagine the sensation would be forced almost entirely into odor. I'd like to try it on animals some day.
"On the other hand, if you ignore it, make no attack upon it, it fades away. It's what I do when I want to observe its effects on others, and it isn't difficult."
He placed a little veined hand upon the instrument, fingering the knobs aimlessly. "Sometimes I think that if one could really study this thing, one could compose symphonies in a new medium; do things one could never do with simple sound or sight. I lack the capacity for it, I'm afraid. How- ever, just a light touch, not enough to confuse the established mental patterns, is sometimes rather interesting. It heightens perception,, releases the psychological censor, accentuates wishful thinking... or expectant dread."
He moved the knobs minutely before Biron could object. The moaning now was sweet cerebral music, which, for an. instant, threatened to become, hollowly menacing before Biron thought of Arta. He thought of her and she was real against the background of the room and Gillbret with the box of dreams in his hand. The music rose to hungry longing more intense than any emotion Biron had ever experienced. She was beautiful and he wanted her....
IT ended and she was gone; he still stood with his fists tight and his heart beating in race rhythm. Gillbret looked hastily down at the sono-visor, as though embarrassed by the intensity of Biron's visible yearning. He should have been amused, yet he was not, and Biron, relaxing unhappily, was grateful for that.
"I suppose it could have great therapeutic value," said Gillbret, "by revealing to us our suppressed wishes and fears — "
"I'd like to ask you a question," Biron said, abruptly.
"By all means."
"Why don't you put your scientific ability to worthwhile use instead of — "
"Wasting it on useless toys? I don't know. It may not be entirely useless. This is against the law, you know."
"The visi-sonor. Also my spy devices. If the Tyranni knew, it could easily mean a death sentence."
"Surely, you're joking."
"Not at all."
- "The Mule" (part I), Astounding Science Fiction, November 1945.
- "The Mule" (part II), Astounding Science Fiction, December 1945.
- "Tyrann (part I)", Galaxy Science Fiction, January 1951.
- Chapter 17 of Foundation and Empire, 1952.