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Topic Name: Recorded Sound from Silence
Category: Advanced Materials
Research persons: Carl Haber and Vitaliy Fadeyev
Location: Lawrence Berkeley Nat. Lab ,1 Cyclotron Rd ,M/S 50R5008 ,Berkeley, CA 94720, United States
Details
The oldest sound supports could be saved by a
revolutionary scanner allowing their numerical retranscription. The unbounded
conservation of the sound inheritance is in sight. It is perhaps a
step of giant towards the conservation unlimited of the audio inheritance
which a team of researchers has just carried out.
It is at the university
of Berkeley that Carl Haber and Vitaliy Fedayev developed a process
allowing to numerically retranscribe the sound contents of the musical
supports oldest, and from which some almost fell into the lapse of memory.
Within this framework, the
invention of the researchers of Berkeley could be the miracle solution for
the safeguarding of these invaluable objects of file. It indeed allows a
perfect numerical transcription without any contact with the weakened
support.
"I had phonograph records as a kid, so I knew sound was stored in a
mechanical profile. I realized that we could use images to figure out in
detail what the groove actually looked like, and use a computer to calculate
the sound. I thought that might be a way to get around the problem of things
being delicate and damaged; you wouldn't have to touch them," Haber says.
Haber already had access to a machine that could make high-resolution
digital scans. Postdoctoral fellow Vitaliy Fadeyev wrote a computer program to
control the turntable and translate the images into sound.
Haber used a narrow beam of light to illuminate the record's surface. The
flat bottoms of the grooves and the spaces between tracks appeared white; the
sloped sides of the grooves, scratches and dirt looked black. The image was
then analyzed by computer. The program found the edges of each groove by
focusing on areas of high contrast. It could correct areas where scratches,
breaks or wear made the groove wider or narrower than normal.
To preserve the phonographic supports most fragile
“Formats” such as the wax cylinder, heritage of very widespread Edison at the
beginning of the XXe century, the disc shellac, or the famous magnetic tape
would be directly concerned with this lucky find. From the nature even of the
materials which compose them, these musical formats are indeed threatened of
destruction. The simple fact of touching them or of trying to read them can
damage them definitively.
The system developed by the two researchers circumvents this problem by
numerically scanning these old audio materials via cameras equipped with
detectors of particles. Combined with a data-processing program conceived to
this end, they succeeded in producing an image of the furrows punctuating
these phonographic supports. This image would allow finally a transcription
the numerical format of the audio contents.
A process in process of improvement
The first test, if it were conclusive, for was as much not shown very
effective. Nearly forty minutes would have thus been necessary for the one
second transcription of sound contents. Solicited by the library of the
American Congress, the group of researchers considered a means of scanner
discs and cylinders more easily. IRENE, a system allowing to re-transcribe in
2D the structure of discs of time, thus was born. It is currently evaluated by
the department files of the library of the Congress. The current 3D scanning
process takes 20 hours to record one minute of sound. But a new version of the
confocal scanner, developed for the dental industry, should reduce that to
about 10 minutes.
A half-dozen physics and engineering undergraduates from UC Berkeley have
been instrumental in speeding the project along. "Students can apply the kinds
of techniques they learn in classes about statistics, mathematical analysis
and signal processing to a project they can really get their arms around,"
Haber says. A Berkeley graduate student in linguistics is poised to join the
project later this summer.
UC Berkeley's Phoebe Hearst Museum and Native Americans are among those who
could benefit the most from IRENE and its sister 3D scanner. In the early
1900s, UC Berkeley anthropologist Alfred Kroeber and colleagues recorded the
legends, songs, customs and voices of dozens of California Indians on some
3,000 one-of-a-kind wax cylinders. Many of these tribes and languages have
since died out or are on the verge of extinction. The LBNL group is now
collaborating with linguist Andrew Garrett and Victoria Bradshaw of the museum
to digitize the Kroeber recordings. Remastering these cylinders could help new
generations of native peoples study their ancestral customs and tongues—and
help carry the sounds of the past into the future.
The group of research works in addition with the development of a
system allowing the scanning of structures in 3D, device necessary to the
transcription of one of the oldest musical supports: the wax cylinder
About Roll of wax
The Gramophone, the speaking machine invented by Edison in 1877, mother of all
the evolutions in the field of the sound reproduction, allows a short vertical
recording on a silver foil sheet placed on a cylinder. In the years 1881-1886,
Chichester A. Bell and Charles Sumner Tainter replace the silver foil sheet
and employ a cylinder out of paperboard covered with wax. It will be again
Edison, in 1888, which will propose a “final” version of the gramophone by
equipping its creation with an electric motor and by producing the cylinders,
initially out of vegetable wax, then out of gum.
Abstract:
For the bulk of the recorded sound history the
audio information was stored in mechanical media, such as a phonograph record
or wax cylinder, via undulated surface incisions (grooves). The grooves shape
and position can be reconstructed without mechanical contact by using
precision optical metrology tools. The surface map thus obtained can be
digitally processed to remove noise artifacts due to damage and wear, and to
convert the groove positional information into audio format. The viability of
this approach was demonstrated on a 78 rpm shellac disk using two dimensional
image capture and analysis methods[1]. The present work expands on these
results. A three dimensional reconstruction of mechanically recorded sound is
reported. The surface of the source material, a wax cylinder, was scanned
using confocal microscopy techniques and resulted in a faithful playback of
the recorded information. The approach holds promise for careful
reconstruction of valuable historical recording, using full surface
information to improve the sound fidelity, as well as means of automated mass
preservation.
Sound Samples
Related Web Sites
About The Researchers:
Carl Haber
ccid: 398516
Tel:72903 (from outside: +41 22 76 72903 )
Office: 40 3-C02 Mailbox: E24910
E-mail: chhaber@lbl.gov
Experiment: ATLAS
Homeinstitute: Lawrence Berkeley National Lab. (LBNL)
Vitaliy Fadeyev
E-mail: VAFadeyev - at - lbl - dot - gov
phone: (510) 486-4169
fax: (510) 486-6738
Address:
Vitaliy Fadeyev
Lawrence Berkeley Nat. Lab
1 Cyclotron Rd
M/S 50R5008
Berkeley, CA 94720
In The Images-
1.A digital scan of phonograph grooves taken by IRENE. The side-to-side
wiggles of the groove contain the audio information. credit: Carl Haber
2.A digital scan of phonograph grooves taken by IRENE. The side-to-side
wiggles of the groove contain the audio information. credit: Carl Haber
3.wax cylinder,
4.The completed digital phonograph scanner, named IRENE, installed at the
Library of Congress. It was developed with funds from the Library of Congress,
the National Endowment for the Humanities, the National Archives, and the
Mellon Foundation. credit: courtesy Carl Haber
5.Researchers Carl Haber and Vitaliy Fadeyev of Lawrence Berkeley
National Laboratories working on IRENE. credit: LBNL
6.Millions of historical sound recordings such as this wax cylinder are in
need of preservation in the United States alone. credit: courtesy Carl Haber.
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