was just playing this frequency file from the internet and i couldn't hear anything because it's like 20,000hz or something and my hearing doesn't pick up anything under 22:
Thing is; i kept wacking up the volume and had it on repeat whilst trying to pick it up (lolz) - forgot and left my room. I came back from the shop and my landlord was just leaving my door as I saw him.
I asked him what was wrong and he told me my housemate upstairs was ringing him about noise from my room which when he turned up at my door, he couldn't hear.
I didn't say anything further and just unplugged my laptop and made my housemate look like a crazy fool.