Intermitant screatch/scream

[CJ_Derv]

Hey guys,

Just wondering if anyone can help, ive recently been getting a screatch/ scream like sound mid range - mid boost,

Now my general thinking is if turbo was on way it would do it throughout boost.... right?

other possibilities im thinking could be slight boost leak maybe nicked pipe or cracked plastic boost pipe (off 406)

or maybe a pulley or something

any ideas