This is what I am working on. It's only an idea I am thinking about for my thesis. I am trying to read as many relative materials as I can find. And so far I got something I would like to post in page so that I could get a trace of it, and on the other hand, probaly you will find it interesting and helpful. If you got any advice of my project, please, please let me know. I need help badly and would be really appreciate of your help.

Critical Band: The concept of the critical band relates to so much of what concerns the psychoacoustician---- thresholds, loudness, pitch, binaural masking, musical consonance, speech,etc. As a purely empirical phenomenon, the critical band is that bandwidth at which subjective reponses rather abruptly change. Thus the loudness of a band of noise at a constant sound pressure remains constant as the bandwidth increases up to the critical gand; then loudness begins to increase. Often, the critical-band concept is used, not to summarize, but to analyze the results of an experiment or to supplement an auditory model. So used, the critical band refers to a filtering process assumed to take place within the auditory system.

Critical Band Frequencies

Number	Lower cutoff frequency (Hz)	Center frequency (Hz)	Upper cutoff frequency (Hz)	Critical band (Hz)
1	0	50	100	100
2	100	150	200	100
3	200	250	300	100
4	300	350	400	100
5	400	450	510	110
6	510	570	630	120
7	630	700	770	140
8	770	840	920	150
9	920	1000	1080	160
10	1080	1,170	1,270	190
11	1,270	1,370	1,480	210
12	1,480	1,600	1,720	240
13	1,720	1,850	2,000	280
14	2,000	2,150	2,320	320
15	2,320	2,500	2,700	380
16	2,700	2,900	3,150	450
17	3,150	3,400	3,700	550
18	3,700	4,000	4,400	700
19	4,400	4,800	5,300	900
20	5,300	5,800	6,400	1,100
21	6,400	7,000	7,700	1,300
22	7,700	8,500	9,500	1,800
23	9,500	10,500	12,000	2,500
24	12,000	13,500	15,500	3,500
25	15,500	19,500	20,000	-