seems to have got very loud above 3k

 my engine seems to have got louder above 3k-3.5k  and also seems to have a rattle to it… i have checked my exhuast as i thought maybe i had caught it as i have now lowered the car and doesnt apear to be blowing… there is plenty of oil in it
im a bit stumped… doesnt soun tapety more just not as it did? if that makes sense… 
 
dont get me wrong the car is running fine… but a new noise in my mind is never good 
 
kris 

Don’t want to sound ridiculous but could it be because the car is lowered and the noise from engine is echoing off road surface and into cabin more?

making the same noise on tarmac, grass and gravel? it sounds like something is buzzing but im having trouble establishing where it is buzzing from other than some where under the bonnet 

it could be the exhaust  erm covers if you can call it that iv got it on mine  its where its clamped around the down pipe and centre pipe like a heat shield bit hard to explain really but on mine they’ve cme apart so there rattleng