Preserving Tapes
Audio recording is an essential part of most
ministry's outreach. It is also a means for
documenting business meetings and sermons. Most
churches that record sermons have used cassette tape
recorders for decades. Cassette tapes were "the
standard." The average full time pastor might have as
many as 150 tapes per year going into the archives.
Today cars come with CD players and DVD players. To
reach the people today with audio, CD's are standard.
"Does it matter how we store tape?"
Tape is nothing more than a strip of mylar with glue
on it. On that glue are millions of metallic
particles. Think of these particles as mini-magnets.
As this strip of mylar is ripped across the head of
the tape deck, a circuit (bias) causes a magnetic
field to turn the magnetic particles. The higher the
bias, the more particles turned, and the better the
sound quality will be. This is why we have levels of
bias to match the types of tape. Normal tape is Low
Bias, Chrome is considered High Bias, etc.
In storage there are many things that happen to the
tape. The most obvious is that over time, the tape
gets brittle, the glue looses it's grip, and the
particles come off. This degrades audio quality
severely. Every time a tape is played (new or old),
particles are left behind on the head and the pinch
rollers. Eventually there is signal loss, mechanical
noise and distortion. There is no solution. Always
try to maintain your tape libraries in a temperature
and humidity controlled environment. It is not so
much the temperature, but the humidity that does tape
in.
The next unavoidable thing is "bleed through" or
"print through." If a tape is stored tightly rewound,
the sound from the under lying layers of tape bleed
through to the top. This is why you might hear a
faint ghost of a song, before the song actually
begins. This is really annoying when the spoken word
is recorded, and it sounds like two people are talking
at the same time. This is why you should never store
tapes tightly rewound. Always make sure that cassette
tapes are stored, loosely forwarded to the end. This
way the print through will happen after the song and
not before. For the spoken word...well it will help a
little.
Another problem that I see is that cassette tape
recorders may have gone years without cleaning,
deguassing (demagnetizing the transport) or alignment.
There may have been hundreds of tapes recorded with
the azimuth (alignment of the head to the tape) off.
So you may have to find a pro that can align the tapes
to your machine.
Why is this an issue? Well, I had been receiving
tapes from a friend's church near Nashville. I love
the pastor. He says it like it is, and I like that.
I was getting cassette albums from years past. I
noticed that the quality was iffy. After talking to
my friend there, I called the pastor to offer my help.
I told him that I would transfer his library to CD
for him. The library would take up less space, and
would have an increased life span. CD-R copies would
cost less than cassette copies, and there would be
virtually no preventive maintenance expenses for CD
burners. So, that is another service that I will
offer now, I guess.
"What should a church record to?"
I would recommend an Alesis Masterlink ML-9600.
Retail is $1700, street price is $700. I will not
give a full review of one here. I will tell you that
I have one myself, and they are great for church
recording. The Masterlink appears to be a dedicated
audio master recorder, that prints to CD-R. Well, it
is in a way. Unlike any other device, it has a hard
drive. The new models come with a drive that allows
for 30+ hours of recording time to the hard drive.
After recording to the drive, a Red-Book CD's may be
burned. Red Book means that it has a Table of
Contents (TOC), and is the same standard as all
commercial music CD's. It will play in any CD player.
A CD-R does not have a Table of Contents, and relies
on a computer, or a player with software to access the
files. The Masterlink would allow the average pastor
to record 30 sermons on the drive before having to
burn a disc. Go to www.alesis.com to learn more, or
contact me and I'll give you more info.
The other options are a Digital Audio Workstation
(DAW) or a CD-R unit. A DAW would allow you to
maximize your resources and provide multitrack
recording and mixing functions. The DAW would allow
for editing, adding intros, outros, etc. A DAW can
also allow for time compression and expansion. If
your pastor is long winded by a 5 minutes, that 5
minutes can be compressed to fit in to the limits of
the CD, without affecting the pitch of his voice.
Boy, if only we could do that in our brains.
Should you decide not to begin recording onto a
Masterlink, DAW, CD-R, please consider how and where
your tape is stored. Tape has a life span of about 10
years. The cheaper the tape, the less life it will
have. If your tapes are playing fine after that
amount of time, that is great. I would recommend
playing it safe, and transferring the most important
tapes onto CD.
"But there's hundreds of tapes!"
I had a question asked of me. "Is it possible to play
a cassette tape at double speed, and record it
digitally at double speed, to save time?" The big
answer is, "NO!" Why not? It sounds logical.
In the cassette machine there are filters that operate
to ensure that there is fidelity at the normal speed.
There is also a phenomenon called "head bump." Head
bump is an physically induced EQ curve, which affects
the low end. By speeding the tape up, frequencies are
lost. All frequencies on the tape double, exceeding
the limits of the circuitry. The head bump also moves
up.
In digital land we have the Nyquist theory. Mr.
Nyquist decided that the sample rate of the recording
had to be twice that of the highest frequency to be
produced. If you were to record at 16-bit/44.1kHz,
(CD quality resolution) that means all frequencies
above 22kHz are limited/filtered. It is even worse if
you were to try MP3's. In MP3 world, the drop off
starts at 8kHz. In addition, it uses pseudo stereo.
That means that one of two like signals is disguarded
to save space, and then a DSP trick is done to make it
appear as stereo when played back. Not a good idea in
my opinion. I have a Pro Tools HD rig that records
at 24-bit, 192kHz, so that means I can record 96kHz.
Big deal. If the cassette player could reproduce it
at double speed, what good is the recording? As you
can see it does not work. You have to do it the old
fashioned way, REAL time.
"That tape is noisy and has drop out!"
If you do not have the time for this, consider a
transfer service. Look for a service that can do
Forensic Audio work, to repair tapes, clean up the
noise, bring out the vocals, do editing, etc. What
good is a prestine reproduction of a bad tape? The
goal is to preserve it in the best condition that it
can be. If you cannot find one in your area, contact
me and I will refer you.
Good luck on your preservation of your ministry's
work. This is not fun. It is not easy. It is
essential. You may meet people in heaven that
benefited from your labor. I know that I have
benefited from the work of Rev. Ralph in Tennessee.
Brent Handy
HA! LLC, Tulsa, OK
P.O. Box 54641, Tulsa, OK 74155
lowdbrent@sbcglobal.net
Preserving Tapes
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