Defective Strings

Prior to the invention of nylon, guitar and lute strings were made from gut, typically sheep intestine. In the 1930s DuPont developed nylon and, according to Segovia, nylon strings for guitar were not available until after the Second World War. He said that if it weren't for those strings becoming available, he didn't see how he could continue giving concerts. I have tried gut strings on guitar and lute and they have a wonderful warm sound. Alas, they also tend to wear out pretty quickly and they are quite expensive. Nowadays guitarists have a wealth of fine nylon strings available at a variety of prices.

But it is quite possible for a treble nylon string to be defective and to understand why you have to understand a bit about the physics of vibrating strings. What all those formulas boil down to is that the frequency of the musical note produced by a vibrating string depends on three things:

• the shorter the string, the higher the frequency of the fundamental
• the higher the tension, the higher the frequency of the fundamental
• the lighter the string, the higher the frequency of the fundamental

The first two are pretty obvious; it is the third one where a problem might arise. We know that we can change the pitch with the tuning pegs by changing the tension and as we shorten the string by stopping it on various frets we also change the pitch. The last item refers to the weight of the string, which we can see as the strings get progressively thicker and hence heavier as we move from treble to bass. In order for the note to be pure, the string has to be the same thickness (i.e. weight) throughout. If there is a place where it is thicker or thinner you will get a confused note as the string tries to vibrate in different ways at the same time. These days, with very precise string winding, it only occurs with the treble strings, the ones made just of nylon. The diameter has to be exactly the same throughout.

It took me years before I noticed that not all strings were good. Back in the old days, about one in three Augustine trebles were defective to some degree. I would typically change the bass strings twice as often as the trebles so that I always had extra trebles. You can't actually see or hear the problem until you install the string on the guitar. Here is what to watch for:

• the sound will not be pure and you will have great difficulty tuning the string
• if you watch the string vibrate, you will notice a jerky vibration, not a smooth one

If you keep an ear/eye open for this you will soon learn to identify defective strings. Mind you, they are far less common than they used to be. Augustine in particular has some new string sets that are much better in this respect, though I haven't tried any lately. Companies like Pro Arte and Hannabach will hardly ever have a defective string. But this post is occasioned by my discovering a defective 2nd string in a new set of Savarez Corum Alliance. It was an Alliance treble that was defective. I haven't noticed a problem with the Cristal trebles.

Here is an interesting program by Valeria Galimova: