Have you ever tuned a piano? For 18 years I thought piano tuning was something that was impossible and never under consideration of things to learn, but that changed this month. Not only did I learn to tune a piano, but even more, I gained a deeper understanding of patience and sanctification.

### A quick overview of how piano tuning works:

Pianos are percussion instruments - when a key is pressed, this pivots the corresponding hammer to strike the strings, which vibrate to produce a sound. The length and tightness of each string affects its frequency (or pitch).

The most common tuning system since the 18th century has been 12 equal temperament (12-TET). This divides the octave into 12 logarithmically-equal parts, one per semitone. Thus, the frequency ratio between each semitone is $e^{\frac{1}{12}\ln{2}}$. This tells us the difference between each semitone, but we need a point of reference: 12-TET is tuned relative to a standard pitch of 440 Hz (A440).

But there’s more! Uprights have 88 notes, but did you know that they have around 230 strings? For the tenor and treble notes, three strings are strung for each key, and for bass notes, the number of strings per note decreases from three, to two, then to one as pitch decreases.

Why are multiple strings used? Even though the strings are hit by one hammer and make the same pitch (hopefully), the point at which the hammer makes contact and the slight difference in supports results in different oscillations of each of the strings. This brings a rich quality to the sound.

#### Implications:

So for each key, there are two things that need to occur:

1. Tuning one string to be the right pitch within the tuning system.
2. Tuning the other strings for the same pitch to be in unison with that string.

Step 1 is historically done using a tuning fork, which will make the A440 pitch. However, modern technology enables us to be lazy and use digital tuners to match pitch.

Step 2 takes more nuanced effort. The ‘ensemble model’ technique - tuning each string one by one - does not work in this case. Ensemble models are a method in machine learning where multiple models are run independently, and the output from multiple models is aggregated. If we tuned the strings one by one, (most) human ears do not do well enough to find the exact pitch. Instead, we tune the strings two by two.

Why does this help? To understand, we need to take a quick tangent into Physics: Sound travels in waves. Waves are defined by their amplitude and their wavelength, where wavelength is the inverse of frequency. When two waves of different wavelengths interfere, the waveforms are effectively “added”. Constructive and destructive interference work together to form beats.

Coming back from our tangent: when two strings have different pitches, this will produce sound waves of different frequencies, and one will hear beats. To tune, one tightens and/or loosens the non-reference string until the sound is clear and without beats.

So given this bit of context on pianos and tuning (maybe more than you ever wanted to know?), here’s the more surprising lessons I learned through tuning:

### Lesson 1: Patience and perseverance

Tuning for unison is a very arduous process. Sometimes a single adjustment will suffice. But sometimes, it will seem to take ages. A tiny adjustment will shift the note from being sharp to flat, and an adjustment the other way will do the other. Most horrifying is when I adjust the wrong string… and then need to re-tune more notes. In these moments of frustration, a word of encouragement is a tremendous help in persevering and continuing to tune. Hebrews 10:24-25!

### Lesson 2: A picture of sanctification

Each string has a very good memory of where it was before, and a tendency to slip back to their former tendencies. A week after tuning, we found ourselves re-tuning some of the notes that had slipped. This time, more attention was given to hammering the keys to make sure the strings hold fast and stay in place. This is actually a great picture of our sanctification: God is our tuner and works for our sanctification – although it is so easy for us to slip into the patterns of the old man (Colossian 3:9-10), God tunes us, so that we are renewed and walking “in tune/unison” with the Spirit (Galatians 5). Just as the tuner hammers on the notes to make sure that the strings stay in their new pitch, God gives us trials to test and strengthen our faith (James 1:2-3), and help us to hold fast (Hebrews 10:23).

Praise God that He works in us what is pleasing to Him (Hebrews 13:21), so that our lives can sing out in melody to Him who loves us so!