Make sure 48V phantom power is turned on (required for studio condenser microphones). Make sure the pad-switch is off. I
assume the line/instrument switch doesn't do anything with a balanced XLR connection but you might want to try it both ways.
That's a directional side-address mic, so make sure you are speaking/singing into the front
side, not the end or the back.
If you are speaking/singing into the mic you should be close to the mic (maybe 6 inches) and speaking/singing with a strong-confident voice. If you are recording nature-sounds in the forest you will be stuck with low levels.
like -0.1-0.1 ...When I check the sound levels they come out around -12db...
Just for reference, 0.1 (or 10%) is -20dB. -12dB is 25%.
Pros often record around -12 to -18dB (at 24-bits). Then, the levels are boosted after recording. The most important thing is that you don't "try" to go over 0dB (100%) because your analog-to-digital converter will
clip (distort) if you try to go over. Nothing bad happens when you get
close to 0dB. Generally, you just need to leave some headroom for unexpected peaks... And if there are no unexpected peaks you didn't really need the headroom.
So, lower
digital levels are OK. That is, it's OK to turn-down the recording level knob on your interface to leave some headroom. But,
low acoustic or analog levels will give you a worse signal-to-noise ratio... When you boost the volume later, you'll also boost the room noise and any preamp noise, and that can sometimes be a problem.
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One more thing - If you record in stereo with one microphone of course you'll get one silent channel so after recording you'll want to convert to mono, or copy the "good" channel into the silent channel.
If you record in mono with one mic into a stereo interface,
you'll be limited to -6dB (while recording) because it's leaving room for the other unused channel to be mixed-in. The clipping indicators on your interface are correct and they will show clipping at -6dB with one input (or 0dB with two inputs). So in this case, you'll need to boost the levels after recording (which you're doing already since you're only hitting -12dB).