Pinyin forms from dictionary published by Foreign Language Teaching and Research Press, Beijing 1984. Pinyin is a very broad phonetic representation as will be seen from the recorded vowels and consonants.
The four tones are-
1. Shang P'ing Shêng, or Upper even.
2. Hsia P'ing Shêng, or Lower even.
3. Shang Shêng, or Rising tone.
4. Ch'u Shêng, or Departing tone.
Description of the tones is difficult (play the recording).
There is regional and contextual variation.
According to one source, for Beijing the first is a falling tone,
uttered somewhat sharply; the second is a curt upper rising tone;
the third is a long rising tone broken in the middle; while the
fourth is a short finishing falling away intonation. (See
Chinese by Jerry Norman C.U.P. 1988 pp. 147, 194-5).