exhaust making a tinny,rattly kind of sound

[YBJLS4]

i got a spoon streets muffler on at the moment, now everytime i start up the car, the muffler makes a tinny, rattling kind of sound.

cold start, continually makes this sound here and there for 2second intervals, then when driving, always makes it at 3,000 rpm. the sound then eventually dies away and doesnt occur after 5min of driving.

the muffler was making some other sound, and it would be faster everytime i drove faster, but i went over a bump and now that sound dooesnt happen nemore

but anyway, why is it making this tinny sound

[mnc]

Could be the insulation in the muffler getting old and deteriorating over the years due to the pollution and exhaust gases?

general wear and tear.

[thaizeg]

Yea it could be. Unbolt the axle back and shake it to hear if anythings rattling inside.