  It is well-known that the non-strictly thermal character of the Hawking
radiation spectrum generates a natural correspondence between Hawking radiation
and black hole quasinormal modes. This main issue has been analyzed in the
framework of Schwarzschild black holes, Kerr black holes and nonextremal
Reissner-Nordstrom black holes. In this paper, by introducing the effective
temperature, we reanalysis the non-strictly thermal character of large AdS
black holes. The results show that the effective mass corresponding to the
effective temperature is approximatively the average one in any dimension. And
the other effective quantities can also be obtained. Based on the known forms
of frequency in quasinormal modes, we reanalysis the asymptotic frequencies of
the large AdS black hole in three and five dimensions. Then we get the formulas
of the Bekenstein-Hawking entropy and the horizon's area quantization with
functions of the quantum "overtone" number $n$.
