Preserving Tapes

By Brent Handy
Contributing Writer
July 22, 2011

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Read more from Brent Handy
How To Preserve You Ministry's Tapes - or Why You Should Pay Someone To Do It For You

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 away. 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









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