Drum machine and measuring method

The invention relates to a drum machine and a measuring method for measuring the collapse angle of particulate matters in a drum. The drum machine is provided with a drum device, a measuring device and a computing device, wherein a light collection unit in the measuring device can be used for collecting scattered light emitted by the particulate matters irradiated by laser light in the drum, and transmitting speckle image information to the computing device; the computing device is used for acquiring a collapse angle based on a certain rule according to the rotation angular speed of the drum, the laser wavelength and the grey level of a speckle image. The method is easy in measuring operation, is small in errors and is high in accuracy. Moreover, the collapse angle measured with the method can be used for measuring the collapse angle being smaller than 0.5 degree of the particulate matters, so that the problems of complex operation and large errors in an existing repose angle measuring device are solved.