How do you make the volume of air pots louder?

Hi, a friend of mine found air pots (we don't keep them, we just freshen them up). We've already put something up for the person they belong to, so don't worry. The air pots are very quiet. I think they're first or second generation. Are they generally that quiet or what is it? I have the third generation and mine are a lot louder. If you know how to make them louder, please let me know. I don't mean that you have to turn it up on your phone. We're not that blonde, but they're very quiet even when they're on full volume.

LG maluuuu