Muffler vibration

[4D56]

Just got my old muffler replaced with a new one. Pero nao-obserbahan ko na nagba-vibrate ito at around 2,000 to 2,200 rpm. Nawawala naman ang vibration kapag ibang engine speed. Ano po kaya ang cause nito and what should I do to minimize or totally eliminate the vibrations?

Thanks =)

Try nyo po pakabitan ng flexible pipe. kinakabit po youn between exhaust ng engine and tambutso. Dati lagi ako napuputulan ng tambutso sa sobrang vibration pro nong nagpalagay ako ng flex pipe, ok n..