[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [ARSCLIST] 78 rpm fragments in archaeological contexts
----- Original Message -----
From: "Oliver Mueller-Heubach" <ommuel@xxxxxx>
I’m an historical archaeology Ph.D. student at the College of William and
Mary
working on a paper for a material culture class. My goal is to create a
methodology for using the 78 rpm record fragments commonly found on early
20th century archaeological sites to help look at issues of class, race,
ethnicity,
and gender. Since it is very rare to find fragments with portions of the
label
surviving, the paper will focus on things like material composition,
thickness,
edge-type, etc. I would like to produce a typology of characteristics that
might
correlate with different economy and deluxe labels, series, and date
ranges.
Ideally, I would like to find a way to read the grooves on the fragments
to help
identify the type of music. Unfortunately, the fragments found are
generally
only1-4 cm. in size. The analog method that occurs to me is to cut a
section out
of a poor condition, non-archaeological 78 with a Dremel-type tool and
then
patch in the fragment and play, listening for the deviation from the
surrounding
song. This would probably prove difficult in terms of aligning grooves and
identifying such a minute section of music, but I will be giving it a try.
I have
seen some reports of digital scanning and reconstruction of broken 78s and
cylinders, but apparently these techniques are being applied to restore
mostly
complete recordings. Is there a way that single record fragments could be
read
digitally to interpret the style of music (or even compare it to graphs
generated
by the practice of re-mastering old recordings and thus match the actual
song)?
I realize this is probably a long shot, but if there is a chance, it would
be a great
archaeological tool.
Thanks in advance
Oliver Mueller-Heubach
What I would suggest is:
1) Determine the groove pitch (number of grooves per inch (or wotever) of
disc
radius. This can be done by measuring the radial length (i.e. at 90 degrees
to the
visible grooves) of the fragment, and counting the more-or-less concentric
grooves
included on the fragment.
2) Have a "blank" (no audio content) vinyl disc containing a content-free
groove area
using the identified pitch.
3) Excise an area matching the fragment from the "sonically-empty) disc,
into which your
fragment can be inserted.
4) Play the result...this should provide excerpts of the original
phonorecord, which may or
may not provide information as to what disc the fragment was part of...?!
Keep in mind that, on the outermost grooves of a 10" 78, a length of .52333
inches of groove
will provide a second of sonic content. As the groove diameter decreases
(and the centre is
approached...), a second's worth of sound is contained on .21 inches of
groove. Since the
groove area is c. 3 inches (radially) wide...if we assume 3-mil (.003")
groove width and
groove spacing (groove + land = .006"), that means the 3" area contains 500
turns of the
spiral. (probably high, since this would result in 6.4 minute 78/'s...?!).
So, let's estimate
240 grooves/radial inch. This figure means that each radial inch contains
about 80 grooves...
and would take very close to a minute to play. Therefore, a 1" x 1" fragment
of a 78, if
played as described above, would provide 80 short excerpts of the recording
lasting
somewhere between two (an outside fragment) to five (inside) seconds each.
Thus, for "inside" fragments, the five-second segment might prove adequate
to establish
the song...possibly the artist...and, when compared with early catalogs or
the "Abrams
Files," the phonorecord itself. Two-second segments? I'm not sure...
Steven C. Barr