What is meant by the duff?

The Shaykh : The duff and the tablah are both musical instruments, but the difference between them is that the duff has one side, while the tablah has two sides. That is to say, if a drum made of wood or other material is covered on both sides, it is a tablah, and if it has only one side, such that it is like a plate, then it is called a duff. The duff is less severe than the tablah, because the tablah, being covered on both sides, has a stronger sound and tone than the duff. For this reason, the scholars said: The duff is permissible, and the tablah is not permissible. Yes. Yes.