Hello,
I have Yamaha N12 and try to record interview using wireless Sennheiser lapel mics BUT in my office I can hear some noises form outside. My question: is there any way I can set-up N12 so it would be less "sensitive" or cut out sound below some level? Is there built in compressor in N12. Any suggestions are welcome. Thanks in advance.

You first need to set up the Sennheiser radio system properly.

Put the microphone in the correct place on the person and address the cable properly to avoid handling noise.

Set up the sensitivity of the transmitter correctly (the problem you are having is more likely here than in the mixer) - 0 for quiet speech, -10 for normal speech, -20 for loud speech/singing, -30 for loud singing.

Set the receiver to line out and put it into the line input of the mixer.

Hello,
I have Yamaha N12 and try to record interview using wireless Sennheiser lapel mics BUT in my office I can hear some noises form outside. My question: is there any way I can set-up N12 so it would be less "sensitive" or cut out sound below some level? Is there built in compressor in N12. Any suggestions are welcome. Thanks in advance. Neither one would solve your problem of sounds leaking in from outside the set. Lower sensitivity would just mean turning down the trim on the input channel with your mic. But that lowers the level of both the voice (desired sound) and the background (undesired sound) leaving their ratio to each other unchanged. Compression isn't likely to help much either, in fact it would probably RAISE the level of noise between the words, just the opposite of what you want. Compression reduces the difference between high and low sounds, making the soft sounds louder in proportion to the louder sounds. You might want to try applying a noise gate in post - it's sort of like an "un-compressor," further lowering the level of sounds (the background) that are below a certain level.

There's no need for a wireless mic for a sit-down interview in an office. Instead, use a hypercardioid mic on a boom positioned just out of frame and close the subject. The hyper is very directional and by experimenting with its position you may be able to put the source of the interfering sound in the pattern nulls. Making sure it is as close to the subject as you can get it without intruding the frame so the level of his voice (desired sound) hitting the mic is as high as possible in relation to the low background noise.