ISO 226

Louder is better, right?

“Is louder better, right? What is it about loud music that excites us? Why do we feel the need to turn everything up? This month, let’s explore why we enjoy it loud.

According to Mat Leffler-Schulman: ‘When we hear a loud sound, our brains release neurotransmitters such as dopamine and adrenaline, which can create a positive emotional response. This effect is often referred to as the ‘loudness heuristic,’ and it can make us perceive louder music as being more exciting, powerful, and emotionally impactful.’

I remember getting my first boombox in the 80s. I was always reaching for the volume. Turning it up, little by little, trying to find that perfect sweet spot of loudness. Loud enough to enjoy but not so loud that my mom would come tell me to turn it down. There is nothing like that feeling when the music just fills the room with a great song!

What’s the science behind why we like it loud? An important aspect of loudness is our human perception of it. Our ears hear frequencies at different levels, as discovered by Harvey Fletcher and Wilden A. Munson. In 1933, they released a paper titled ‘Loudness, its definition, measurement, and calculation.’ This led to the development of the Fletcher-Munson Curves, which were later used by the International Organization for Standardization (ISO) to develop ISO 226. These curves show how our ears perceive volume as it goes up. To simplify this principle, as the volume goes up, our ears perceive the low and high frequencies going up more than the mid-frequencies. Hence the ‘curve.’

So why does this matter? First, let’s look at human hearing. The human hearing range is generally accepted to be from 20Hz to around 20,000Hz. As we get older, we lose a lot of the higher frequencies. By the age of 40, the high-frequency range has lowered to around 15,000Hz. It should also be noted that our hearing is extra sensitive around 2-5kHz.

For a little fun, put on some headphones and go to https://www.szynalski.com/tone-generator/ if you want to get an understanding of what some of these frequencies sound like. At what frequency do they get uncomfortable? What’s the highest you can hear? As I write this, I am 49 years old. Right around 6,303Hz, the frequencies start to hurt. The highest I can hear is 15,502Hz. To do this, I have to turn the volume all the way up, and even then, I can only faintly hear it.

Whether it’s music, human speech, or any other sounds we hear, these frequencies all come into play. We can use a spectral analyzer to get a visual representation of them. When we turn up the volume and the Fletcher-Munson Curve is in effect, the frequencies don’t change. Only our perception of them changes. The extra low frequencies ‘fill’ the space we are in, and extra higher frequencies provide more perceived clarity and energy. The music sounds bigger, fuller, clearer, and more energetic. Basically, to our ear, louder does mean better!

To compensate for this, in the 70s, many home stereos featured a ‘loudness’ button that would boost the lows and highs to provide that additional perceived energy without the need for turning up the volume. In other words, the loudness button was there to make lower volumes sound better by boosting the lows and highs. Most people didn’t understand this and just kept it on all the time. I know I did!”

To learn more about Fletcher-Munson curves Composing Gloves has a great YouTube Video on it.

Next month we will talk about loudness and EQ.

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