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The Anechoic Library

The anechoic library is an example of a technology designed by a fictional professor with a terrible business plan, but I liked the concept because of its great potential for unintended consequences. Noise-canceling signals are sent from thousands of speakers built into the walls, the floor, and even the furniture. Unwanted sounds are canceled near the occupants’ ears. Our heroine uses her knowledge of the technology to trick the system into allowing her to listen in on an antagonist’s conversation. 

Referring to the fictional library as anechoic is ironic because the word means echoless and the noise-canceling system sends out intentional echoes to cancel out ambient noise. However, anechoic chambers are quiet rooms, so I thought the name would be appropriate.

The following is a passage from The Spark Anomaly that illustrates this technology:

 

Cathy entered the spacious library and immediately felt overwhelmed by the deafening silence. Although hundreds of students chatted and argued around the large square tables, the only sounds she could hear were her own footsteps and the rustling of her hands in her pockets. The place seemed surreal, as if she was watching a TV show with the volume muted. Floor-to-ceiling bookshelves mostly filled with engineering texts and periodicals towered over the busy students. 


It had been years since she had entered the library, but the absolute silence combined with the obvious chaos brought back a flood of memories. Just after she had turned seven, her father had taken her to the library to show her the new noise suppression system, which he called the NSS. Cathy remembered being humiliated by the outing. Of course, her father had simply been trying to teach her how the system worked, but she was a shy child who just wanted to go home. She smiled. Many of her strongest memories were of times when things had gone horribly wrong. But somehow, they didn’t seem so awful anymore. Now they were cherished memories. She would give anything to feel humiliated by her father’s antics once more. Knowing that he would never embarrass her again left her with a dull ache. 


The NSS had been designed by Frank Spitzer, one of her father’s former graduate students. Her father had been thrilled when it was installed in the library. He had described Frank as brilliant, ambitious, idealistic, and naïve. Spitzer had dreamed of selling the NSS to libraries around the word. But as far as Cathy knew, this was the only library that had installed his system. After graduation, he had taken out advertisements, gone to building construction trade shows, and even managed to get a small business grant. Several magazines wrote articles praising his brilliant invention, but he never got the business off the ground. 


Several years later, a large conglomerate came up with virtually the same design and made a fortune selling it to restaurants. Unfortunately, Frank never thought to protect his intellectual property with patents. But the conglomerate did. They hired a team of corporate lawyers and sued Frank for patent infringement even though he had come up with the design first. Legally, Frank had been in the right, but he couldn’t afford to mount a defense, so in the end he lost everything. 


Hearing a familiar voice behind her, Cathy froze. “Look who’s here,” said Maria in a whisper. Shit, Cathy thought. She knew immediately why Maria’s voice had carried through the NSS sound protection, but that didn’t make her feel any better. Cathy didn’t feel embarrassed, just nauseated and drained from all the emotional encounters. Why did I come to the library? I should have stayed home. It’s all Soona’s fault, Cathy thought wryly. Ignore them, she told herself. Just ignore them. 


Cathy stood up straight, kept her back to them, and walked as bravely as she could to an empty table. I should never have come here, she thought miserably. 


“I’ve never seen her in the library before. I can’t believe that the queen of suck up is actually lowering herself to associate with the rest of us,” Mark said. 


“Quiet, she’ll hear you,” Maria hissed. 
 

“The NSS is operating. She can’t hear a thing,” Mark responded casually. 
 

“I don’t trust that system,” Maria replied. 
 

Cathy smiled to herself, realizing that they didn’t understand how the NSS worked. Well, her father’s boring explanations were useful for some things. Cathy put her book bag on the table and stood, recalling her father’s incredible enthusiasm as he described how the system worked. 
 

“There are thousands of speakers and microphones embedded in the floor, the ceiling, and even the tables,” her father had said, waving his arms about the room as if he owned the place. He pointed at the ceiling. “And dozens of video cameras are watching our every move.” Her father pointed down. “Each speaker emits an inaudible chirp to continually calibrate the system.” 
 

Cathy quietly chuckled to herself, remembering that at the time she had thought that chirping birds were living in the speakers. A chirp was a technical term for a sound or signal that increased its frequency over time. Cathy smiled. Her father had always been enthusiastic about things that most people took for granted. 
 

“Sound waves are tiny little gusts of wind that push the air back and forth, causing vibrations that can be sensed by your ear,” her father had explained. “The noise cancellation system transmits a sound wave that pushes the air in the exact opposite direction so the sound disappears.” Cathy had rolled her eyes. Her father had told her many times how sound waves worked. 
 

Her father raised his finger. “But let me tell you a secret that most people don’t know. The sounds aren’t canceled everywhere — only in your ears.” 


Cathy had been surprised by this. Her father nodded happily. 
 

“It’s like a balloon. You can pinch it in the middle, but it always pops up somewhere else. It’s called sound nulling.” Cathy had shrugged. 
 

“By shifting the sounds coming out of each speaker in time, the ‘nulls’ can be placed at arbitrary locations in the room. Sound takes time to travel from place to place, and there are only certain locations in the room where the sound from the speakers and the sound of your voice arrive together to cancel each other out and create a null. If you could step out of a ‘null,’ you would not only hear the original noise, but you would also hear the noise-canceling echo produced by the speakers. Video cameras figure out where your head is, and the sound nulls are placed in your ears so that you can’t hear the background noise. Students can work in silence even though sound waves are bouncing all around the room. 
“Let me show you how to fool the system,” her father had said, opening a large paper bag that he had brought into the library. “Put this over your head.”

 

“No, Daddy. There are hundreds of people around,” Cathy had said nervously. 
Her father put the bag over her head. Mortified, Cathy remained stationary, feeling like an idiot, knowing that if she fought her dad, she’d look even more foolish. After a few seconds, the noise of the library filled her ears. She could hear at least three radios blasting and dozens of voices overlapping. Her father pulled off the bag, and silence returned almost immediately. 

 

“Daddy, let’s go. Please?” she had begged. 
 

“No, there’s more. Did you know that the NSS can null individual conversations?” Cathy had shaken her head no, to which her father had nodded yes. “Well, it can. It looks at your eyes to see who you are talking to. Let’s run another experiment,” her father said. 
 

“Just tell me, Daddy,” Cathy had begged. 
 

Her father continued. “We can look at each other from across the room, and the system will know that we’re talking because it recognizes our eye contact. You could stand over there.” Her father had pointed across the room. “I could stand here, and we can have a conversation in a whisper while not hearing anybody else in the room. The NSS will cancel out all other sounds in the room, but it will amplify our conversation in our ears.” 
 

“Very interesting,” Cathy had said dryly. “Can we leave now?” she had asked, tugging her father’s shirt. 
Cathy sighed, bringing herself back to the present. Obviously, Mark and Maria had been staring at her while they were talking about her. The NSS had thought that they were talking to her, not about her.