Tuesday, November 17, 2009

Fun with Damaged Tapes

Damaged materials are fun. Looks weird, right? But it’s true. We in the audio staff naturally focus on the conservation and preservation of naturally decaying and obsolete materials. Every so often, however, we come across a very badly damaged item, at which time it can be fun to concentrate on such a freak and fix it.

A recent anomaly was a damaged microcassette. Its shell sides had begun to come apart where they were originally molded together, and somehow the tape got stuck in this space. Although the content is always important, this particular tape included an interview with a recently deceased personage. For any one to hear him again, I had to take drastic measures.

The tape would not budge from the crack. More important, no microcassette machine had been designed to baby the tape, and it would be irresponsible to play it on a regular machine, even if I were able to wind it back inside the shell. Instead, the plan was to transfer the tape to a cassette shell and digitize the interview using our cassette machine, which has far superior tape-handling and output electronics than the standard microcassette machine.

The first step was to house the tape in a new shell. Breaking apart the original shell revealed severely crinkled and very thin tape. With the tape free, I could wind it off the microcassette hubs (the wheels) and onto a standard cassette hub, as illustrated below by manually coaxing the tape off the original hub and onto the new one. It’s not the most glamorous task, but needed to be done.

Preparing for winding. The beginning of the original tape was attached to a new cassette-size hub and leader on a cassette splicing block. The old microcassette hub is on the left.

End of winding: attaching the new cassette-size tail leader and hub. Note the broken, original shell at left.

Ready for transfer.

This, however, is only the first, though hardest, step. The next part is digitizing and manipulating the audio. Because I just created Frankenstein’s tape monster, things didn’t run exactly as one might expect. First, the microcassette format moved the tape in the opposite direction from that of the cassette format, so the interview played in reverse.

Second, the microcassette format plays at roughly 15/16 inches of tape per second, whereas the normal cassette runs at twice that speed; thus the interview played back twice as fast as it should, making it sound like Alvin and the Chipmunks in reverse. I then employed some digital trickery to return the interview to its proper pitch and direction, making it ready for the researcher.

To conclude, this is a good example of the importance of digitizing our audio materials before researchers can use the recordings. Both microcassettes and normal cassettes are often problematic; this includes the far more common split or broken tape. With open-reel tape, we see even worse problems: sticking, shedding, stretching, squealing, etc. (No, not all problems start with the letter “s.”) Discs are worse yet. It would be a shame to have a problem with the original occur during research and permanently damage a recording. This is why access copies are digital.

1 comment:

  1. This sounds similar in some ways to my project of transferring old reel-to-reel tapes to digital audio, with of course, the digital slight of hand needed to correct the speed. The original recordings were at 1-7/8 ips, my tape machines's slowest setting is 3-3/4 ips. Did I mention there are 4 separate archived tracks? ~whew~