about the noisy sound
you know I just want to describe the micro is a little noisy.so could I say it like this:
1:I heard a noisy cacophony in your microphone.
2:I heard an intermittent noisy sound in your microphone.
so I want to know how I can give a correct description of it very natively just like people in English speaking countries.

Question

about the noisy sound 
you know I just want to describe the micro is a little noisy.so could I say it like this:
1:I heard a noisy cacophony in your microphone.
2:I heard an intermittent noisy sound in your microphone.
so I want to know how I can give a correct description of it very natively just like people in English speaking countries.

Answer

I think Deep Blue's answer is spot on - if you're speaking and it is not clear, too noisy, then you call that distortion.

If you're not speaking and you hear noise, you call it "static" (if it is constant), or "crackle" (if it is intermittent). If you're not sure, just say "there is noise".

A couple of extra notes:
- "cacophony" is a rather formal word which means noise.  I can tell you looked in a dictionary. ;-) It literally means "bad-sound" and refers to bad music or unorganised sounds (eg. busy traffic).
- beware of using too many adjectives! "Intermittent noisy sound" is unnecessary.  Just use "noise".  Same for "noisy cacophony" - we already know cacophony is noisy.  Start with the noun - if it makes sense, then no need for an adjective.

Answer

There is distortion in your microphone.