How to determine cause of white noise with new microphone/preamp?

Question

I've been meaning to start making videos of covers of songs with vocals and acoustic guitar, so i purchased a Shure M58 microphone with a blue icicle XLR-USB. My Laptop is a macbookpro with touchbar and i have a lenovo adapter for the usb-usbc. I am constantly hearing a white noise kind of sound but I can't determine if it is just the blue icicle itself, or maybe some other cause that i wouldn't know about as a novice ?

I'ved tried: repositioning/moving microphone, unplugging charger from laptop, plugging icicle directly to microphone, tightening the cables.

So at this point I am not even sure what the problem is, between the microphone, icicle, and could it be the usb-usbc lenovo adapter ? Would i have made a better choice purchasing the X2U preamp ? (I can still return icicle)

Here is a soundbyte with my tests, the first clip is from the Voice Memos app, the second clip was recorded on GarageBand and exported to Final cut Pro, not sure why it is so weirdly distorted... Any help is appreciated ! And it seems i need a lot of help ! lol

Answer 1

The text in your video states "no noise gate" but there very very much is a noise gate involved here at some point of the processing since the background noise most certainly is being gated. It would appear that the gain of the M58 (don't you mean SM58?) in your example use does not mesh well with the quality of the icicle adapter. If the adapter is the one I think it is after cursory search, it is intended for condenser mics with phantom power. You might get a bit less noise by switching off the phantom power but if I read it correctly, that isn't possible.

Some older dynamic microphones (like typical ribbons) will work in nominal operating conditions but are not protected from getting fried when anything goes wrong in the wiring (like a short between ground and one of the signal wires).

Signal levels of condenser microphones will lead to best results: be sure to turn the analog volume control up as far as it will go in your use case without causing distortion.

However, quiet speech and singing are quite different levels. Maybe the signal-to-noise level for singing will work out for you. If not, equipment with better preamps and/or conversion noise levels may be called for.