The tam-tam is either struck or rubbed (or “stroked”).
The instrument is not struck exactly in the middle but about a hand-width (depending on the size of the disc) from the center, since it is at this point that the greatest volume and the lowest notes are produced. The ideal striking spot varies from instrument to instrument however, and the percussionist must locate it by trial and error, because missing it even by only a few centimeters can radically change the sound.
Like the gong, the tam-tam vibrates most in the center and least at the rim. It is for this reason that it is suspended by the turned-up rim. The sound contains a great many inharmonic partials.
The tam-tam is struck with a number of different mallets, usually with special tam-tam mallets. The larger and heavier the instrument, the larger the mallets must be and the greater the force that the percussionist must expend to produce a full-sounding tone.
In addition, notes take longer to develop fully on larger tam-tams and the overall pitch is lower. It is also harder to damp a large tam-tam. In fact, very large instruments at high volume levels require two percussionists to damp them.
Judging the attack for a piano tone is difficult and it is very hard to control the dynamic level.