Those who live around train tracks often learn to distinguish the sound of one train vs. another: a passenger train sounds different from a freight train; one railway uses a different sounding engine vs. another, etc. The same is true for connoisseurs of automobiles: experts can tell by the hum of the engine what type of car is passing by. My dogs know that one truck parked in front of the house means a friend is here, while another truck parked there is visiting elsewhere.
My hearing is piqued by the sound of the mail truck. Although the community mail boxes are several houses away, I can tell when the mail truck is pulling up and can distinguish that sound from all the other passing traffic. It is an efficient skill to have!
Whether your ears are tuned to trains, cars or mail trucks, remember that the nuances are not in the hearing of the sound, rather the meaning our mind associates with it. You and I both hear the same traffic in the background and the same noise the postal vehicle makes, only it is in my brain that the distinctive sound of the truck signals it is time to go get the mail.
Be intentional about the meaning you choose to attach to sounds in your world. You may not need to distinguish the mail truck, but perhaps you become attuned to the sound of a client walking in the door, the grumble of a client before they walk out the door, a teapot just before the water boils or a child just before they have a meltdown.
Be intentional about giving meaning to what you hear so you bring the background to the foreground.