I’m on Windows with a Samson Meteor USB mic. Now I hear this.
There is a sound on this file. You might have to load it to audacity to see it. It’s a very slight quivering from silence to just a notch of sound above the zero level. It sound like a kind of humming wow. I think it’s coming from the microphone. Is this something I just never noticed before? Or am I hearing things? I know I can see this in audacity.
There’s two different forms of interference on that …
#1. The slowly pulsating deep hum at 90Hz, which is probably derived from 60Hz mains electricity.
and #2. the constant whine at 1kHz and multiples thereof, (2kHz, 3kHz, 4kHz, etc),
The pulsating deep tone is fixable with a notch filter to remove 90Hz.
The whine requires several notches at 1kHz intervals, there’s an Audacity plugin designed to do that : Mosquito Killer.
Use the least number of notches to remove the interference as notches also cause collateral-damage to the sound you’re recording, (e.g. maybe use Mosquito-Killer on 4 notches rather than 6 ).
Generally, “this kind” of noise gets into the mic’s analog electronics through the USB power. (The same thing can happen with USB powered audio interfaces.) With a different computer the noise will probably be better, worse, or just different. And, different mics can be more, or less, sensitive to power supply noise.
If you get hiss (white noise), that’s usually generated by the preamp. With USB mics, the preamp is built-into the mic. All amplifiers generate some noise.
The mic was not making this noise for years. I dropped it and now I get this humming. I spose it never helps to drop a mic.
So I put this mic in storage last year until I would have time to get it fixed. I took it out while sorting my stuff and thought to plug it in using a different cable and lo! - it’s working fine! Then I switched to the original cable and still, it’s fine. Is there some kind of Psychology of Electronics going on here? Apparently, if I leave this microphone to itself, it works out it’s own problems!
Wow, a self-healing microphone! You could make serious money if you can make all microphones do that 
Maybe it got religion and it’s a miracle? But seriously, what’s up? This reminds me of when we would give the TV a whack and it worked. But I dropped the mic and that’s when the problem started. Now it’s gone. I wonder if there was just some coincidence? Like, I dropped the mic and then that line got a short in it at the same time? Then I tried it with a different cord and it worked. Then I switched back to the original cord and it just happened to not short out? Could that sound have come from a short in the line?
My guess would be a loose wire / connection. If the earth wire is disconnected, you will get a lot of buzz / hum and very little actual signal.
The mains-hum part could be dependent on the position of the USB cable, (and the user), in relation to sources of mains electricity. Moving/touching the cable could make the mains-hum reappear.
Having said that, I have audio-equipment which for some reason has seasonal mains-hum: it disappears in winter. Maybe humidity ?.
You can do conspiracy theories if you want, but I’m going with a slightly damaged cable connection when you dropped it. Unplug both ends of the USB cable and plug them both in again. Maybe twice. The year in the middle has nothing to do with it.
There was a servicing elf that caught all sorts of abuse and flame by having people unplug USB cables and touch the tips of the connector very slightly to their tongue before replacing them. People wrote learned essays about why this would never work thus missing the point completely. To go through this exercise you have to unplug the cable and plug it back in.
Too many people were just going “yeah, yeah, I replugged the connection,” and doing no such thing.
Koz
That’s right up there with Rory Sutherland’s idea of making the last five pills in a course of antibiotics a different colour. Same pills, but the completion success rate goes way up because of the clear goal.
Koz
Huh. Well, that was a year ago, I posted this. Whatever happened, it was coincidental to dropping the mic. I don’t remember if it was plugged in at the moment. I may want to have someone test that one cable. But can anyone who reviewed the sound file substantiate that hum as a short in the line?