October 14, 2019 - Robert John Hadfield
Audiotape Skid Marks
The Friction of Sound
Like most kids, I loved riding a bike when I was young. And for most of the young boys I spent time with, riding the bike was all about speed. And as we developed the skill of riding fast, we also developed a parallel skill, braking.
At first braking was just about stopping the bike effectively, but over time it was more about stopping the bike with style. It was a big accomplishment when we could stop the bike and leave a big skid mark. That long black mark on the asphalt was a true accomplishment.
Of course that black line on the road came with a price. We were literally scraping the rubber off the tires and leaving the residue there on the ground. Over time this would literally weaken the tire.
I doubt many people ever really thought about it, but a similar thing happens when you play a cassette tape. When you play a cassette it is literally dragging across something called a play head. And there is a something called a pressure pad built into every cassette that presses the tape firmly against the play head as it passes along. Next time you see a cassette, look closely under the tape, you will see a little piece of felt that is mounted on a very thin piece of metal, usually copper. If you want to learn a little more about that, watch this video we made about the pressure pad.
Similar to a tire skidding across the road like we did as kids, the tape will leave residue on the play head. Cassette tape is made of a very thin piece of plastic coated with iron oxide. When the oxide becomes magnetized it “records” sound. But as that oxide rubs along the play head on a cassette deck, it leaves a tiny bit of residue. And although it certainly causes damage to the tape, much like a skid damages a tire, most of the time the amount of residue that comes off the tape is so minimal that it’s not worth noting.
The problem it causes is not on the tape itself, but on the play head.
Because tape needs to have solid contact with the play head as it passes by, it leaves a tiny bit of residue. Over time that oxide residue builds up on the play head, and eventually it will prevent the tape from making a solid connection to the play head. At first this will diminish the high frequencies in your tapes. In other words, tapes will sound muffled. Eventually the quality of the sound will diminish to the point that you can barely hear anything.
You might think your tapes are bad or that your deck has an insurmountable problem, when the truth is, a simple cleaning will bring that cassette deck back to sounding like new.
Although you can buy tape-head cleaner, you can also use 100% alcohol. Put a little alcohol on a q-tip and rub it across the play head in the cassette deck. If you play tapes frequently, and if you rarely clean the head, you will see a brown residue on the q-tip. Just repeat the process a couple of times until you no longer see brown on the q-tips.
As tapes age the oxide wears off more easily, and eventually old cassettes will begin to lose significant quality each time they are played. Do yourself a favor and don’t wait another minute. If you have cassette tapes or video tapes you need to preserve, send them to us and let us help you make that permanent archive of your audio.