wow.. really a great improvement from the 80s...hahaha....
some further correction here....
actually.. a resonator as it sound...it use resonance as tool to cancel out wave length..
so the mid box you guys talk about or the rear box can be a resonator too...
bullet in general is round tubing with pack or un pack, so if pack... it is relying absorption to absorb the sound wavelenght , if is not pack, is actually using resonance theory to lower down the noise, but a perforated pin hole bullet relying on resonance for noise reduction ... well... let just say it wont work right ... a scale hole , or louvred one will work much better...
exhaust, silencer, muffler and bla bla bla... well.. is just the term used in different country, you go to australia, no one know what is a bullet... but they know what is a hotdog... hahaha.... you go to uk , you say muffler they give u a ear muffler, the call them the silencer...... if you go us , you say you wan a silencer... die lor... you get the silence for your gun .... hahhaaa...
japanese vehicle manufacturer hate fiber.... because it cost alot.. and it doesn last long... so 95% of their vehicle , the exhaust system is purely resonance , sound cancelling design.
the europeans in the other hand.. really love their packed muffler.......and seriously.. they do sound much better compare to japanese oem muffler.. but harder to produce and cost alot..... now alot of the european exhaust comes in hybrid mood which combine cancelling and absorption, so that is why their car exhaust sound so little....
the mid muffler, why the oval shape will sound lesser than bullet, is because... they are prettier ? haha.. of course not... given the same size and material, the oval shape will sound lesser because as the sound wave travel it will go back and forward, the oval one give the wave to travel in different direction and back forward in different time.. not like the round one where only uni direction all bound back to center at more or less same time.....
if you pay little more attention... you will seee the european car model muffler is very very weird in shape , with bump here there... well.. these are not just for weird look to make you pay more .. but it custom design to fit in the car and also sound the right pitch.... if you fir an a6 muffler in a4, it will not sound the same.....
true... the american and european exhaust people make million dollar room just to tune the exhaust product to the right pitch, some even hire 3rd party engineering company to create signature sound for specific model of car and also bikes..... but as for the japanese... well.. i don see much coming from there.... maybe i will update myself more... the europeans had been doing this for decades, well before i in automotive line...
regard the catalytic converter ... well is alot of misconception.. the catalytic converter convert , convert harmful gas to less harmful gas so Malaysian, don cut the catalytic converter as soon as you get the car OK ? be more eco friendly please...... and they don filter... what filter in exhaust system is only DPF (Diesel particle Filter) and which is still not enforce in malaysia yet......