Pendergast pulled again, and a voice rumbled from the back. "Non lo voglio. Va' via!"
Pendergast rang again, insistently.
A gray shape materialized behind the glass: an enormous, stooped man in a leather apron with long gray hair and a gray mustache. He waved both hands at Pendergast in a shooing motion. "Che cazz'! Via, ho detto!"
Pendergast took out a business card, wrote a single word on the back, and slipped it through the mail slot in the door. It fluttered to the floor. The man picked it up, read the back, and went very still for a moment. He looked up at Pendergast, looked down at the card-and then began the laborious process of unlocking the door and raising the grate. Within a minute, they had stooped beneath the arch and were standing in his shop.
D'Agosta looked around curiously. The walls of the shop were almost completely covered with the hanging bellies, backplates, and purflings of violins in various stages of carving. It had a pleasant smell of wood, sawdust, varnish, oil, and glue.
The man stared at Pendergast as if he were staring at a ghost. He was wearing a dirty leather apron, and he removed a pair of sawdust-covered glasses in order to peer at the agent more closely.
"So, Aloysius Pendergast, Ph.D.," he said in almost flawless English. "You have gotten my attention. What is it you want?"
"Is there a place where we can talk?"
They followed him through the confines of the narrow shop-perhaps eight feet wide-to a much larger space in the back. Spezi indicated for them to sit on a long bench. He himself perched against the corner of a worktable, folded his hands, and stared.
In the rear wall, D'Agosta could see a stainless-steel door, grossly out of place, with a single small window. On the far side of the window was a gleaming white laboratory, racks of computer equipment and CRTs bathed in unpleasant fluorescent light.
"Thank you for agreeing to see me, Dottor Spezi," Pendergast said. "I know you are a very busy man, and I can assure you we will not waste your time."
The man bowed his head, mollified slightly.
"This is my associate, Sergeant Vincent D'Agosta of the Southampton Police Department, New York."
"Very pleased." The man leaned forward and shook his hand. He had a surprisingly strong grip. Then he sat back again and waited.
"I propose an exchange of information," Pendergast said.
"As you wish."
"You tell me what you know of Stradivari's secret formulas. I will tell you what I know of the existence of the violin mentioned on my card. Naturally, I will keep your information secret. I will write nothing down and speak to no one about it, except to my associate, who is a man of complete discretion."
D'Agosta watched the man's deep pale eyes stare back at them. He appeared to be thinking about, perhaps even struggling with, the proposal. Finally he nodded curtly.
"Very well, then," said Pendergast. "I wonder if you could answer some questions about your work."
"Yes, but first: the violin. How in the world-?"
"First things first. Tell me, Dottore-since I am a man who knows nothing about violins-tell me what makes the sound of a Stradivarius so perfect?"
The man seemed to relax, evidently realizing he was not dealing with a spy or competitor. "This is no secret. I would characterize it as very lively. It is an interesting sound. On top of that, it has a combination of darkness and brilliance, a balance between high and low frequencies-a tone that is rich but as pure and sweet as honey. Of course, each Strad sounds different-some have a fatter tone, others are lean, even harsh; some are thin and quite disappointing. Some have been repaired and rebuilt so many times they can hardly be called original. Only six Strads, for example, retain their original necks. When you drop a violin, it's always the neck that breaks. But there are about ten or twenty that sound almost perfect."
"Why?"
At this, the man smiled. "That, of course, is the question." He rose, went to the steel door, unlocked it, and swung it open, revealing two hard-disk recording workstations and racks of digital samplers, compressors, and limiters. The walls and ceiling were covered with acoustic foam paneling.
They followed him in, and he shut and locked the door behind them. Then he switched on an amplifier, pulled up the faders on a nearby mixing console. A low hum began to sound from the reference speakers set high in the walls.
"The first really scientific test done on a Stradivarius was performed about fifty years ago. They hooked a sound generator to the bridge of a violin and had it vibrate the instrument. Then they measured how the violin vibrated in return. An absurd test, really, because it has nothing to do with the way a violin is played. But even such a crude test showed the Strad gave back an extraordinary response in the two-thousand-to-four-thousand-hertz range-which, not at all coincidentally, happens to be the range of sound that the human ear is most sensitive to. Later, high-speed computers allowed real-time processing of a Strad being played. Let me give you an example."
He turned to one of the digital samplers, used an attached keyboard to select an audio sample, sent the output to the mixer. The sweet sound of a violin filled the room.
"This is Jascha Heifetz playing the cadenza of Beethoven's violin concerto on the Messiah Stradivarius."
A complex series of dancing lines appeared on a monitor sitting behind the mixer. Spezi pointed at them.
"That is a frequency analysis from thirty to thirty thousand hertz. Look at the richness of the low-frequency sounds! They give the violin its darkness, its sonority. And in the two thousand to four thousand range I mentioned, see how lively and robust it is. This is what fills the concert hall with sound."
D'Agosta wondered what any of this had to do with Bullard or the murders. He also wondered what Pendergast had written on the business card the man was still clutching in one fist. Whatever it was, it had clearly made this man remarkably cooperative.
"And these are the high frequencies. Look how they leap and flicker, like the flame of a candle. It's these transients that give the Strad that breathing, trembling tone, so delicate and fleeting."
Pendergast inclined his head. "So, Dottore-what's the secret?"
Spezi reached for the sampler and the music stopped. "There is no one secret. It was a whole catalog of secrets, some of which we've cracked, others we haven't. For example, we know exactly what kind of architecture Stradivari used. With computerized tomography, we can map a Strad perfectly in three dimensions. We know all there is to know about Stradivari's designs for the belly, backplate, purfling, f-holes-everything. We also know just what types of wood he used. We can make a perfect copy."
He turned to one of the computers, typed again, and the image of a beautiful violin appeared on its screen. "There it is. An absolutely perfect copy of the Harrison Strad, down to the very nicks and scratches. It took me almost half a year, back in the early eighties, to complete." He glanced over at them with a mirthless smile. "It sounds dreadful . The real secret, you see, was in the chemistry . Specifically, the recipe for the solution Stradivari soaked his wood in, and the recipe for his varnish. This has been the thrust of my research ever since."
"And?"
The man hesitated. "I don't know why I am inclined to trust you, but I do. The wood Stradivari used was cut in the foothills of the Apennines and dumped green into the Po or Adige Rivers, floated downstream, and stored in brackish lagoons near Venice. This was purely for convenience, but it did something critical to the wood-it opened up its pores. Stradivari purchased the wood wet. He did not season it. Instead, he soaked it further in a solution of his own making-as far as I can deduce, a combination of borax, sea salt, fruit gum, quartz and other minerals, and ground, colored Venetian glass. He soaked it for months, perhaps years, while it absorbed these chemicals. What did they do to the wood? Amazing, complex, miraculous things! First, they preserved it. The borax made the wood tighter, harder, stiffer. The ground quartz and glass prevented the violin from being eaten by woodworms-but it also filled in the air spaces and gave it a brilliance and clarity of tone. The fruit gum caused subtle changes and acted as a fungicide. Of course, the real secret lies in the proportions-and those, Signor Pendergast, I will not tell you."