A good way of practicing these exercises is to listen to the isolated frequency (when the band pass filter kicks in) and then listen to the pink noise again.Do so, back and forth, a few times. Now listen to the pink noise only. Can you spot that frequency and “mentally isolate" it as much as possible from the rest?.Can you mentally shift from a frequency to another up and down on the spectrum? Imagine you engage an imaginary peak filter and sweep it up and down very slowly. Can you predict how it will sound?This is easier said than done but this is an incredible exercise for your brain. Let’s be honest. You will not be doing so during an actual session but the fact that you kept practicing will turn your brain into an automatic “frequency radar” even though you are not aware of it.The brain functions as a powerful "magnifying glass" depending on what aspect of the sound you want to analyze. At some point, pink noise starts to sound like it's made up of single "notes" and you will learn to pick the correct frequencies thanks to their relations in terms of octaves or smaller "intervals".What kind of sonic character do you feel each particular frequency has? Try to label them in your mind according to what they sound like to you. I.e "1kHz is honky, 6kHz is somewhat "dry" and sibilant, 16kHz is "Airy", and so on. These characteristics are common to all sounds and all instruments.TIP: Practice these "band pass" exercises with Pink Noise first and then using a couple of songs that you know very well in terms of instruments used, arrangement, and so on. Make sure these songs are in a different key too. You will discover interesting things.