The Secret of Fresh Strings

We continue our intermittent study of the sonic properties of instruments with a look into how much the sound is effected by changing your guitar strings! It’s pretty fascinating (to me at least!)

For me, changing your strings is a bit of a chore, and at the end of the day does it make it sound really that much better? Well today let’s put that to the test.

We go a lot of guitar re-stringing in the shop so I took a moment to measure the sounds of a guitar with pretty old, corroded strings. New strings should be brilliant silvery nickel, but these were pretty black with corrosion.

Corroded strings

Now for some spectral analysis. We went for the extremes and recorded the top E and the low E:

Low E (Old)
High E (Old)

But what does this strange wiggly line mean exactly? Here’s a quick run-down: Every sound we hear can be broken up into the different frequencies that combine to produce it. The purest sound we can hear is a simple sine wave:

We can keep adding sine waves together to make any note we like. The different combinations of these will produce a different timbre, or texture of the sound. A flute is a very ‘pure’ sound with only a few sine waves needed to reproduce it, the human voice is much more complex, with many sine waves combining to add greater ‘texture.’

On the graphs we’re looking at today the low frequencies are on the left, going all the way up to the nearly inaudible high frequencies on the right. The higher the peak, the stronger that particular frequency is resonating.

A musical note is going to be a combination of it’s lowest pitch, which is usually the one we hear it as (the fundamental) and the harmonic overtones, the extra notes taken from the harmonic series, most strongly at an octave and a fifth. It these overtones that give the sound most of its character.

Strong peaks near the fundamental give us an impression of ‘deepness,’ the first dozen or so give more ‘richness’ and the upper section gives a feeling of ‘brightness.’ The shape of the peaks matter too, the more concentrated the peak are the clearer each note, and harmonic will sound.

Now it’s time to change the strings. One thing is certain: they look and feel a lot nicer!

Back to the spectrograph:

Low E (New)
High E (New)

This is where is gets a bit tricky. From a side-by-side comparison there seems to be little in it. Let’s superimpose them, and see if the differences become more apparent.

Low E (Combined)

Now the differences can be seen a bit more clearly. The old string is in white and the new string is in blue. For the low E there is a stronger fundamental note at 172HZ, as well as stronger harmonics between 500-1000. This will certainly explain a greater depth and richness of tone. There is also less of a drop off after around 4Hz, adding a little more brightness.

High E (Combined)

Again the old string is in white, and the new string is in blue. The differences in the high E are a bit more subtle. The two main points of interest seem to be a much higher peak around 750Hz and higher peaks at each harmonic from 2K upwards. These suggest the fresh string has more ‘brightness’ than the old one, which matches what we seem to perceive.

So that settles it! Changing your strings really does change the sound. Helping people understand how the condition of an instrument effects the sound is a big part of work here at Ackerman Music. If you’re near one of our shops and would like a free tune-up and some free advice on the condition of your guitar you’re always welcome!

I’d like to thank everyone who stuck around to read my interpretation of these strange looking graphs, and hopefully gained a little insight into how fresh strings make a difference.