Noise Begins to Get on Gus's Nerves

            "This is the guilty party right here, Mr. Adamus." Adamus looked at him with a baleful eye. "If you're going to immerse that in some sort of volatile fluid,the other three have already done so."

            "But - " "It didn't do any good."

            Gus took the lid off anyway, and looked closely at the cleaner. He shook it, and nothing rattled. He dipped it in solvent, and nothing dissolved. Gus shrugged and put it back in position over the carburetor. When he started the engine, the whistling was there as before.

            "Did they look at anything else?"

            "I suppose so, but I don't know anything about engines. I couldn't tell you. All I know is that if this thing goes on much longer, the school board will ask me to resign. They'll let that young upstart of a clarinetist take over ."

            Gus gritted his teeth and stomped over to the Chrysler again. It was getting ridiculous, and that flat sound was beginning to grate on his nerves.

            He tightened up the bolts on the intake manifold and the sound didn't change. He then poured light oil around the intake gasket. None of it was drawn in, removing the possibility of a leak there. Something in the carburetor itself?

            Gus attacked the carburetor with new fervor. Something small and mischievous was causing it all. The noise should have been simple enough for a juvenile Tinker-Toy artist to find. Instead, it was behaving like some sonic will-o'-the-wisp!

            He didn't expect to find anything inside the carburetor, since it wasn't likely that foreign matter would be jammed in there without upsetting the running of the engine. But it never hurt to look and make sure. The net result was nothing.

            "Maybe I'd better go," Adamus suggested hopelessly.

            "No, not yet. Let me fool with it for a while. The darn thing is beginning to grab me by the hair!"

            "Look, Mr. Wilson, I'd be perfectly happy if you'd fix it so it played just plain A-flat. Anything but that quarter-tone. Here, I'll show you - " Like a man possessed, he reached a skinny arm into the car and snatched something from the rear seat. When he straightened, Gus saw that it was a flute. Placing the slender instrument to his lips, Adamus blew one piercing note. "There! That's A-flat! Make it whistle that, and I'll say no more."

            "If I find it at all," Gus returned grimly, "I defy it to make so much as a peep."

            The thing was growing to preposterous proportions, and Gus considered the situation. Sound sometimes performed peculiar antics. A noise could seemingly come from a certain spot, when actually it originated on the other side of the engine.

The Canary Continues to Sing

              Gus took an oilcan and fed a few healthy squirts to the fan-belt pulley, lubricated the rotor in the distributor and searched for loose metal that might be vibrating. Yet the whistle persisted, like a one-note, tone-deaf canary,

            Gus turned in disgust and sat down on the bench beside Adamus.

            "Once a month, sometimes twice, just like clockwork, I get a customer with a bug that defies location - for a while. People have brought me twitters, squeaks, howls and moans, but this is the first time I haven't been able to find it!"

            "Maybe I'd do well to sell the car."

            "No, you don't have to go that far. That noise isn't anything that's going to cause it to stall on you."

  Adamus Explains His Strange Gift 

            "Mr. Wilson - " Adamus no longer looked like a character, but like a serious, saddened little man under a great nervous strain - "Mr. Wilson, it's either fix the car or sell it. Maybe you think I'm odd, like all the rest, and it's probably true. But it isn't artistic temperament that causes me to behave like this over a small noise. I believe I mentioned it before. It's my absolute pitch. I am able to identify notes, or name individually the notes in a complex chord of music, merely by the sound. Therefore, when an instrument or a singer drifts off key by only a hair, I can spot it immediately. Most people with the gift are not overly bothered by a note that's a fraction above or below what it should be. But with me, it's as distressing and painful as an allergy. I become nervous and irritable, and can't concentrate on my job properly. For a minute or two it doesn't bother me, but when I have to listen to it for 40 minutes while I drive to school every morning...Well, how can I make you understand?"

   Gus Gets Back to Work

             "I do understand." Gus smiled sympathetically. "A rough-running engine will get my nerves to hopping after a while, too. But just relax and let me work on it. We're bound to spot the trouble soon."  Gus got up. The words were far more confident than the way he felt, but he couldn't quit yet.  He started the motor again, locked the throttle at an engine speed just sufficient to start it whistling, and began looking.

            Gus went over the engine inch by inch, probing, testing, until as far as he was concerned, it was still the air cleaner. He felt sure now that he had been right in the first place, and that taking other causes and the deceptiveness of noise into consideration had merely led him on a wild-goose chase. The air cleaner had to be it. He removed the suspect without turning off the engine. The whistle stopped.

 The Case of the Baffling Baffle           

            "I don't care what those three mechanics told you. This is what does it, but I don't know why. It's not a complicated gadget. This copper mesh, coated with oil, filters dirt out of the air before it goes into the carburetor. And to deaden the sound made by the carburetor, a couple of resonance chambers inside act as...whoops!" Gus grabbed at the air cleaner as it bobbled in his hands - he had almost dropped it. "They act as a baffle. Not much could happen to it unless some foreign matter got inside somehow, or if it was dropped..."  He stared at Adamus with a sudden light in his eye.

            Gus turned the cleaner over and looked at the bottom. It was coated with a layer of grease and dirt, where the mechanics' rags had not reached. Gus wiped it clean. There were no cracks or holes to catch his eye, but there was one small dent. It was no bigger than the nail of his little finger. He showed it to Adamus.

            "That? I'm only a musician, but how could that little dent cause all that hideous noise?" "I don't know for sure, but let me check." 

 Gus Goes By the Book

            Gus pulled out a manual on the new Chrysler and turned to some diagrams. He studied them for a while and inspected the air cleaner critically. He shook his head. "I don't think I ought to try removing the dent. I don't think we'd get the best results that way. It would be quicker and more certain to try a new air cleaner. I don't have one here, but I can run down to Martin's and pick one up. Won't take long - want to wait?"

            "Oh sure." Adamus' tone was resigned, though not too hopeful. "I'll wait."

            In a quarter of an hour, Gus was back. He unpacked the shiny new air cleaner and installed it on Adamus' car.  "Now we shall see."

            Gus and Adamus listened in breathless suspense as Gus started up the engine and slowly raised the speed. The engine reached close to its peak r.p.m. without a whistle.

            "Thank heavens!" Adamus exulted.

            "That dent was it, all right. I guess someone dropped it while it was being cleaned."

            "Mr. Wilson, I congratulate you. But I still don't understand about the dent."

            "Well, I wasn't too clear on it myself. It was merely a hunch until I looked in the book here." Gus got the original cleaner and showed Adamus how the thing worked.

 Just a Little Dent Did It 

            "Remember before, I told you this thing acts as a baffle? Well, to begin with, you have a felt pad in here, just under the cover, that absorbs the hissing noise produced in the carburetor as air strikes the throttle blade. "Now, there's also quite a bit of noise down here in the intake manifold, and to quiet that down there are two resonator chambers, one of high frequency and one low. These chambers neutralize the noise by reflecting sound waves exactly out of phase with the original sound waves. What I had never considered before is what might happen if a dent changed the shape and volume of one of those chambers. That little dent was enough to cause the frequency of those sound waves to be in phase with the original sound, instead of the opposite as it should be. Just a quirk of chance, I guess.

            "But at any rate, it would be too difficult to remove that dent to the perfection needed. The new unit isn't expensive."

            Johnathan Adamus ran a glad hand through his hair and grinned. "Mr. Wilson, I don't care if that gadget is made of platinum - the noise is gone." He leaped into the driver's seat like a steeplechaser mounting his favorite steed, raced the engine and cocked an ear. "Just listen to that rhythm. Not a whistle or squeal. It's music to my ears!"

 END