This study was designed to evaluate the
voice quality of VoIP referring to packet loss
rates of 0%, 2%, 6%, 10% and 20%
approximately, with G.729 codec and G.711
(A-law) codec. Therefore, there were ten
conditions to test. Following [25], each
condition has been conducted with at least 24
inexperienced subjects/participants or at least
240 inexperience subjects/participants
totally, who were science and technology
students, Thai native speakers, in KMUTNB
They had few criteria of homogeneity which
only consisted of the range of age
nationality, and the background of education
(based on science and technology in the
same university).