D-weighting

Okay, so imagine you have two bags of toys. In one bag, there are a bunch of small toys, like marbles and legos. In the other bag, there are bigger toys, like teddy bears and action figures. If you were to count the number of toys in each bag, you might think that the bags have the same amount of toys in them. But, if you were to weigh each bag, you would notice that the bag with the bigger toys weighs more.

Similarly, when we talk about sound, some frequencies (or pitches) of sound are "bigger" or louder than others. When we want to represent the loudness of a sound in a way that matches how the human ear perceives it, we use something called a weighting filter.

One common weighting filter is the A-scale or "dBA" weighting. This means that the loudness of a sound is measured not just by how much sound energy it has, but also by how much our ears are likely to pick up on those specific frequencies. The A-scale emphasizes the frequencies that our ears are most sensitive to, and downplays the ones we don't hear as well.

So, in a way, the A-weighting filter is like weighing the bag of big toys more than the bag of small toys, because the big toys take up more space (or, in this case, have more sound energy) and are more noticeable to our ears (or, in this case, have a higher frequency).