Make sure your USB port is supplying enough power. I have the same interface and on my laptop cannot use Phantom Power from that interface because it gets the power from USB and my laptop doesn't supply enough power for the interface and it's Phantom Power. You may need to try a powered USB hub seeing that the interface doesn't have it's own power supply, you're relying on the USB port alone for your power.
It still sounds like there may be an issue with the phantom power being either low or nonexistent. USB power out of some computers can struggle to keep up if you have several devices plugged in. (mouse, keyboards, memory sticks). A condenser mic with insufficient phantom power will produce a very low signal.
As Ujn Hunter mentioned, try a powered USB hub.
Just to try it out, I plugged it into a powered hub that I had lying around but wasn't using. Not sure if it made a difference.
While searching for answers, I found a reply saying that the loud click noise that happens whenever starting or switching to another program (one that uses audio equipment, anyway, including headphones) may be the interface shutting on and off. Or it shuts off to conserve power, and back on when going into one of those programs, if no audio has been used for like 5 or so minutes. It also said to solve it by shutting off unneeded audio devices in device manager. That worked at first, but then next time I turned on my PC, back to clicks- even with unneeded devices still off.
The powered hub so far has not seemed to solve that. But it's only a minor problem.
I think that something is off here. The MXL 440 should put out a decently strong signal. And while the Xenyx preamp on the UM2 isn't exactly great, it should be more than capable of amplifying the mic input signal to a respectable strength without having to totally crank the input gain.
I suspect a defect with either the mic or the interface. The best way to know if it's a defective component is to be able to test with other similar components. If you've got a friend that has a mic, cable, or interface, I'd try to swap something out and see how it works.
I do have a friend with audio equipment. He lives kinda far but I'll go to his place this weekend with my stuff to see if it works for him. He's been helping me via chat and so far he can't do much when not in person.
Sitting close is how close? For speaking you may want to be around 8"(20cm) to 12"(30cm) and be talking directly into the grill on the side of the mic with the MXL logo. The mic has a sensitivity spec of 15mv/PA which is about middle of the road for condenser mics and should give an OK signal into your interface. With the distance I suggested and a normal speaking voice I would guess the gain knob might be about 12 to 2 o'clock to get the UM2's green signal LED to flicker on peaks of your voice depending on distance. Don't be shy about getting up a bit closer and being closer can reduce room noise and depending on the mic can yield a more 'radio' like voice (bassy) due to proximity effect.
The MXL 440 needs 48 +/- 4 vdc. The MXL 440 manual states the current draw is < 3.0ma which the UM2 'shouldn't' have a hard time supplying.
I do have a Behringer UMC404HD and a few mics that are around 15mv sensitivity. If I get a chance sometime today I may try hooking things up to get an idea of where the gain might be to get a decent signal into Audacity or Reaper.
Your suggestions seemed to have fixed the volume problem (when the mic decides to work, anyway). =)
Also a few more things I just noticed today:
1. Sometimes I'll turn on my PC, everything plugged in as it was when I last shut it off, and the mic won't work on anything. The interface signal lights up as normal, but my PC won't read it. Then I boot up FL Studio. This starts the ASIO codec, and it begins working (on other programs as well). Is there a way to get ASIO to start when I boot up my PC?
2. It will not work on Discord. This program seems to give everybody trouble. But the odd thing is, it works in the mic test in Settings! If I click Let's Check in the Voice & Video tab of Settings, I hear the loud click, it turns on, and shows my mic working. Then I get a call (or make one), and hear the click again, and mic shuts off (for Discord, anyway). I cannot figure out why this happens.
The irony here that my cheap 3.5mm mic and headset worked perfectly fine on everything, yet all this stuff is giving me headaches of trouble and causing me to spend all my free time trying to solve this. I just wanna give up at this point. I'm not going through all of this every time I turn on my PC. I just want one mic I can use for everything.