From Top Quarks to the Blues

[Dave Monroe]

April 16, 2004
 
>From Top Quarks to the Blues

Berkeley Lab physicists develop way to digitally
restore and preserve 
audio recordings 
Contact: Dan Krotz (510) 486-4019, dakrotz at lbl.gov 
 
The 1995 discovery of the top quark and singer Marian
Anderson’s 1947 rendition of Nobody Knows the Trouble
I’ve Seen may seem unrelated. But through an
interagency agreement with the Library of Congress,
the same technology used to study subatomic particles
is helping to restore and preserve the sounds of
yesteryear.
  
Library of Congress-sponsored research will help
Berkeley Lab physicists digitize audio data encoded in
the hill-and-valley surface of Edison wax cylinders.
This three-dimensional scan of a portion of a cylinder
was acquired with a non-contact confocal optical
probe, and provided by STIL SA of Aix-en-Provence,
France.   
  
“We developed a way to image the grooves in a
recording that is similar to measuring tracks in a
particle detector,” says Carl Haber, a senior
scientist in Lawrence Berkeley National Laboratory’s
Physics Division who developed the technology along
with fellow Physics Division scientist Vitaliy
Fadeyev. 

Their work could ultimately enable the Library of
Congress to digitize the thousands of blues,
classical, Dixie, jazz, and spoken word recordings in
its archives. The mass digitization of these aging
discs and cylinders will both preserve the nation’s
musical history and make it accessible to a wide
audience. 

The collaboration, which is rooted in a February 23rd
agreement between the Library of Congress and Berkeley
Lab to conduct media preservation research, takes
advantage of Berkeley Lab’s decades of experience
developing ways to analyze the flood of data generated
by high energy physics experiments. This work,
conducted at accelerators located at Fermilab and the
European Center for Particle Physics in Geneva,
requires the ability to image the tracks made by
elementary particles as they hit detectors, and find
these tracks amid a jumble of meaningless noise. 

“We thought these methods, which demand pattern
recognition and noise suppression, could also analyze
the grooved shapes in mechanical recordings,” says
Haber. 

To test their hunch, Fadeyev and Haber turned to a
precision optical metrology system used by Berkeley
Lab physicists to inspect silicon detectors destined
for the upcoming ATLAS experiment, which will search
for a theorized but never observed particle called the
Higgs Boson. Instead of measuring silicon detectors,
however, they programmed the system to map the
undulating grooves etched in shellac phonograph discs.
The images were then processed to remove scratches and
blemishes, and modeled to determine how a stylus
courses through the undulations. Lastly, the stylus
motion was converted to a digital sound format. 

The result is a digital reproduction of a mechanical
recording, with each wiggle, bump and ridge in the
recording’s grooves faithfully captured, and each
scratch ironed out. In this way, The Weavers’ 1950
rendition of the classic Huddie Ledbetter (a.k.a.
Leadbelly) song, Goodnight Irene, is closely mirrored
— minus the hisses, pops, and scratches. The same goes
for Nobody Knows the Trouble I’ve Seen. The nearly
60-year-old mechanical recording sounds worn and
scratchy, but the digital rendition rings clear, just
as Anderson sang it in 1947.
  
“We had to use the metrology system in a new way, and
measure a groove before we even knew its shape,” says
Fadeyev. “This enabled us to develop a non-contact way
to measure delicate samples without the need for much
operator intervention. It also has the potential to
digitally reassemble broken discs.”

Next, Fadeyev and Haber will advance the study of ways
to recover damaged and worn cylinders, as well as
study the entire three-dimensional profile of a disc’s
grooves. Although still under development, the
technology could eventually give the Library’s staff a
better method to restore some of the 500,000 items it
provides preservation treatments to each year, from a
collection of nearly 128 million items in all formats.


"The groundbreaking research that our colleagues at
Berkeley Lab are undertaking signals an important new
direction for preservation of collections of this
type, which we hope will be of benefit to libraries
and archives everywhere,” says Mark Roosa, the
Library's Director for Preservation. 

In addition to preserving the past, mass digitization
gives the public greater access to thousands of old
recordings, some so fragile that even the touch of a
stylus could damage them. Of course, mass digitization
hinges on shepherding the technology far beyond its
current research-and-development stage, which is
familiar work to Berkeley Lab physicists who have
designed and built detectors that have gone on to
observe elementary particles like the top quark. 
 
http://www.lbl.gov/Science-Articles/Archive/Phys-quarks-to-blues.html


And see as well ...


Sound Reproduction R & D Home Page

http://www-cdf.lbl.gov/%7Eav/


Atomic Scientists Bring New Life to Old Vinyl LPs 
	
June 10, 2004

NPR's Madeleine Brand talks with NPR's Ira Flatow,
host of Talk of the Nation Science Friday, about new
techniques that can make old, scratchy vinyl
recordings sound like new. The process was developed
by scientists who usually work to understand the
nature of subatomic particles.

http://www.npr.org/features/feature.php?wfId=1952722


		
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