The muffler with perforated tube produces better
transmission loss result than simple expansion
chamber at all frequencies. So, it can be concluded
that it is required to place a perforated tube inside the
muffler. Newly designed muffler with elliptical
perforated tube is superior to cylindrical perforated
tube muffler for sound attenuation up to frequency
2100 Hz. It is found that for new proposed muffler
transmission loss increases by 7-9 dB .After 2100 Hz
cylindrical perforated tube muffler have higher sound
absorbing capacity.So, conventional cylindrical tube
muffler could be better choice for higher frequencies
but for low to medium frequencies range elliptical
tube muffler could be used.