The Ken Slater Tapes
In the mid 1990’s, I opened a transfer business that was closed at the end of 2021.
The purpose of the transfer business was to provide services for those who found
old media. Before then, I generally avoided consumer formats because almost no
one adhered to the standards. However, that changed when I got into archival
formats and realized that there was a lot of family history that needed to be
transferred. I structured the fees to be affordable for the average person as long
those fees covered the cost of equipment maintenance and supplies. Others that
provided transfer services, said that my hourly rate was too low. Then, institutions
discovered my services. I was hesitant to turn the business away because they too
are always searching for funding.
The Ken Slater Tapes was a project that I transferred in 2020 and 2021, for
Chippewa Historical Society
For this project, I was
initially contacted by Charles Taylor who knew Ken Slater through his father and was
familiar with the collection of audio tapes.
The tapes were in the possession of Beth
Acker and her husband. Charles Taylor helped to assess the importance of the
tapes and Beth built a spreadsheet to document everything.
Ken Slater documented the history and folk lore of the state of upper Michigan
(known locally as the upper peninsula) by recording interviews with the people who
had lived and worked there, including several interviews with representatives of the
Chippewa and Ojibwa Native American tribes. The recordings spanned about 20
years, beginning in the late 1940’s (the dawn of consumer tape recording in the US)
to the late 1960’s. Some of the tribal elders did not speak English and had to have
an interpreter. Most of the people interviewed were elderly and recounted their
experiences from the late 19
century and the early 20
century. Besides peoples’
homes, the interviews were conducted in
homes and hospitals, wherever the
interview needed to be held.
On one particular tape, I could hear the pump of an iron lung in the background.
Although the majority of the recordings were about the upper peninsula area of
there were a couple of recordings about the Pacific Coast of the US,
which included the migration from Michigan in the 1800
Ken Slater started this project when the Brush tape recorder first became available.
A Wollensack T-1500 is still with the family. However, there must have been another
tape recorder used because many tapes were recorded in
T-1500 was available. There were three recording formats involved. Most of the
tapes were recorded
1/2TR. mono. There were five paper base tapes recorded in
the Brush mono format (a unique full track format). Additionally, there were, at least,
two tapes that were recorded full track mono. The full track mono tapes were
recorded externally and sent to Ken. I asked about previous recordings or
technologies and apparently there were none.
I feel that I got to know Ken Slater through his work. Overall, he was a good
recordist and paid attention to the details, as the vast majority of the tapes were well
recorded and, except for the earliest recordings, were voice slated. The interviews
were typically recorded at 3-3/4 IPS. When more fidelity was needed, 7.5 IPS was
used. The stories told by his subjects were interesting, and I found myself listening
to them while transferring the tapes.
The tapes consisted of one hundred eighty-one reel-to-reel tapes. One hundred
sixty-eight were on 7” reels and there were thirteen, 5” reels. One hundred twenty-
four of the transferred tapes were sent to The Chippewa Historical Society, twenty-
one were family recordings of interest and thirty-six were not wanted or blank.
One hundred thirty-one were acetate base tapes. All were recorded 1/2TR. mono.
The brands included Irish (all types), Permo and Scotch. There were approximately
twenty-one acetate base tapes in plain boxes. I suspect that this tape was
purchased in bulk (or, in the bargain bin) as almost all were poorly slit and some
were spliced. This particular tape did not fare well with the mold remediation
process. Of the acetate base tapes, thirty-six were moldy and thirty-three were
There were thirty-three paper base tapes (Permo brand, T-88R). Since the majority
of the paper base tapes were 1/2TR. mono, I suspect that they were reused.
There were seventeen polyester base tapes of various brands and all were recorded
1/2TR. mono. Four were moldy when received and all were isolated. Most of the
polyester tapes were 1mil (1800 feet) and played for 1.5 hours at 3-3/4 IPS.
A few were .5mil (2400 feet) which played for 2.5 hours at 3-3/4 IPS.
In 1925 Ken Slater was married to Ada Giles, according to his niece, Beth Acker.
Ken originally stored the tapes in a metal storage cabinet in a woodshed attached to
their house in Hulbert, Michigan. The woodshed had no heat, had some gaps in the
wood and snow would blow into the shed in the winter. The tapes were exposed to
heat in the summer as well. Being in the middle of the woods in the North of
Michigan, the temperatures would never be hot by most standards, although there
might be one or two hot days in the summer. The woodshed was also plagued with
mice, squirrels and insects. The metal storage cabinet helped protect the tapes from
the larger critters.
Ken remarried in 1966 and moved the tapes to a house he had built in Traverse City,
Michigan. Unfortunately, he stored the tapes in cardboard boxes in the attic area
which was not insulated. It got very cold in the winter and hot in the summer, as the
side where he stored them faced the West. Winds and lake effects from Lake
Michigan and the West Bay didn't help either. So, the tapes were, once again,
exposed to harsh conditions.
The tapes had been tossed out in 1987, the a result of a house cleaning, and were
rescued from a dumpster by Beth and her husband. When the tapes were rescued
from the dumpster, they were moved to Clarkston, Michigan and stored in an air
conditioned basement in that same metal storage cabinet. The tapes were moved to
Irons, Michigan in 2016, to a finished, air conditioned basement. The tapes were
shipped from Michigan to Southern California in 2020 and 2021 where my studio
Thirty-six of the acetate base and four of the polyester tapes base tapes were moldy
when received and had to be separated for treatment. I’m not sure if it was mold or
fungus because I observed both light and dark spots. For the sake of simplicity, I’ll
refer to the problem as mold. Some spots appeared on a few of the tapes
(apparently) as a result of the tapes adjusting to a dryer climate.
Those tapes were
judged as low to moderate and not removed and placed with the other moldy tapes.
However, they were treated for mold.
The mold remediation process that was used
I chose white vinegar because of the acetate base tapes. I normally use denatured
alcohol on polyester base, but any kind of alcohol will damage acetate. I could have
used hydrogen peroxide, but you can’ft mix it with vinegar and I felt that white
vinegar would work best on the boxes which were to be saved.
The remediation process was completed outdoors. While wearing a surgical mask
and rubber gloves, I sprayed the tapes and their associated boxes with white
vinegar and set them in the sun to dry. The reels of tape were turned at least once
while drying in the sun. This was done about four times over the course of a week.
Then, while suited up completely in personal protective equipment (PPE) and
wearing an N95 respirator, I wound the tapes from one reel to another, one at a
time, using an 8mm film editor that had been modified by yours truly. While being
transferred, the tape was wiped, on both sides, with a cloth soaked in white vinegar.
The original reel was then soaked in denatured alcohol, dried and the tape was
rewound while being wiped (a second time) with a vinegar cloth. The tape box was
sprayed again with vinegar, before the reel was placed in it, and the whole thing was
set indoors to dry. After about 2 days, the tapes were checked for any signs of mold.
There was none. The tapes that were judged as low to moderate received the same
treatment as those that were isolated except that they were not treated using the
8mm film editor. Instead, they were wiped with a vinegar cloth in both directions,
while being leadered by me. At the end of the day, all equipment, including the work
surfaces, was sprayed with 91% isopropyl alcohol.
Of the twenty-nine paper base tapes, seventeen were stuck to one side of the reel.
and six of those were judged as high priority.
Fused may be a better term for this, as there was some kind of process that
happened over time. Apparently, a chemical (or chemicals) that was used in the
oxide or perhaps to bind the oxide to the backing reacted with the plastic used in the
reel. Some reels were worse than others, indicating that storage conditions were a
factor. There was no budget for chemical analysis, so I moved on to inventing a
process for un-sticking the tapes:
I selected a piece of ¾” plywood, slightly larger than a 7” reel, and covered the work
area with strips of 2” masking tape. I traced the circumference of an empty 7” reel in
the area where I added the masking tape and placed two padded screws
strategically on the edge of the tracing. I then screwed my homemade jig to the
edge of the workbench so that I could push against the reel to be operated on.
I started by using the thinnest blade possible. After several tools, I discovered that a
commercial pastry knife, I had bought at a yard sale, worked the best because I
could use both hands to apply pressure. I wore a pair of cutting gloves (the kind that
chefs use), since one hand was on the blade of the knife. The tape pack stayed
intact during the process. For the un-spooling process, I used the Shuttle Mode of a
tape deck as slow as it would go. The reels that were stuck the worst had the most
breaks. Paper base audio tape is very, very fragile and sometimes the breaks
involved every wrap.
For getting the end of the tape out of the ¼” reel, I sharpened the end of a wooden
stir stick. Obviously, I wound up with a reel of audio tape that had many splices.
Some of the splices were very long because the tape had torn longitudinally. In the
end, it was worth it because all twenty-nine of the paper base tapes played just fine,
although some of them had several splices.
All tapes were leadered on both ends and checked for recorded format and integrity.
Leader on both ends of the tape will protect the outer layers of the recorded material
and provide some isolation at the hub from the threading slots. Plus, having leader
on both ends provides the ability to transfer the entire recording, because some
consumer tape recorders were very good at recording right to the end of the tape.
The paper base tapes were primarily leadered with paper leader. The exceptions
were those paper tapes that were over full. Those tapes were leadered with plastic
leader. The acetate and polyester tapes were leadered with plastic leader.
Some of the acetate tapes had the original factory tab that had to be cut off in order
to add the leader. In those instances, the original tab was placed in the box. The rest
were secured with masking tape. Masking tape was also used as markers on some
of the tapes and had to be removed before the tape was transferred.
The tapes were transferred and shipped in two groups:
For the 1
group, the audio signal was split into 2 RME Multiface A/D converters.
Each converter was controlled by its own computer, one running at 44.1kHz and one
running at 96kHz and neither computer was connected to the Internet.
After digitizing about half of the 1
group, I realized that it would be better if the
tapes were played only once because of age and fragility so, I changed my workflow
for the 2
For the 2
group, the tape decks were played into a MOTU M2, A/D converter that
was controlled by a computer running recording software at 96kHz. The1/2TR.
mono, tapes were transferred as two channels (one pass). All of the those files were
then edited to one channel each (mono), The backwards channel** was reversed,
and then both channels were re-sampled to 44.1 kHz. All of the original files
(transfers) were saved. The editing for listening was done on a copy of the 44.1 files,
which became part of the deliverables. For the listening files, the blank space was
shortened to about 3 seconds, some of the recorded hum was removed, and the
files were adjusted for gain so that they will all be the about same volume. This was
done for both groups. Sides 1 and 2, of the transfers (tapes) were not joined.
All tapes in the #2 group were played heads out, (from the beginning) regardless of
the reel designation or recorded material. Thus, on the tapes that were 1/2TR.
Mono, Side 1 may have not been the beginning of the recording. On those tapes,
Side 1 is the Left channel and Side 2 is the Right channel. However, when
separating the files, every effort was made to put things in the proper perspective for
Of the thirty-six tapes that were not wanted, those that had been recorded were
transferred at 48kHz.
The recording software used was iZotope RX. The editing of the digital files was
done with iZotope RX and Sound Forge.
Frequency analysis of the supplied material showed an average frequency response
from 50Hz to about 10kHz. The full-track mono tapes, recorded at 7.5 IPS, showed
a slightly higher frequency response of 12kHz or so.
The 1/2TR. mono tapes were transferred using an Otari MTR-15.
The full-track mono tapes were transferred using a Nagra 4-L.
The Brush format tapes were transferred using a Pioneer 1020Q (a 4 channel,
Quarter track), using channels 2 and 3.
Ken Slater (1900–1983) always said that he lived during the best years.
He got to see people go from horse and buggy to landing a man on the moon.
Ken could talk to anybody, king or pauper. From a genius to the mentally
**In the analog era, I used to make copies of master tapes backwards because
the copy comes out sounding better. Both tape decks have to be carefully aligned
(which should done anyhow). I used to use the analogy of a cymbal crash when
explaining the process; A cymbal crash (sonically) has a vary steep leading edge
(Rise Time), then trails off into infinity. A tape head is a coil that is wound around a
piece of steel that is shaped somewhat like a horse shoe. Thus, it does not have a
steep rise time. So, playing a cymbal crash backwards provides a better analog
copy because the tape head can track the rise time better.
I would like to thank all of those who helped to edit this document, especially my
daughter: Megan R. Bailey, Ph.D.
© Corey Bailey Audio Engineering
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