Need Help With Mates Exhaust

Hello all

my mate owns an EK civic also and he has a 2" system with hi flow cat and sports muffler on the back....

there seems to be a HOLLOW NOISE coming from the exhaust ???

you can hear the deep exhaust noise but in that noise there is a HOLLOW noise as well...

i took it to work put it on the host and i could see nothing wrong..
i tightended the gear shifter and the noise is still there ???

does anyone know what it is ??????

could it be a problem with the tip ?? seeing he has dual exhaust tips on it ??

Hole in the system somewhere or a cracked weld.

mmmm he has checked it out for holes or cracks

Was it a cat and back or full exhaust?
DId you put a flexi on the exhuast? the donut joins can give way if you change your exhuast and do not use a flexi. Othewise you should take it back to the shop and ask them