Combination phase plug, and compression driver and speaker using same

A compression driver, comprising:

• a housing, having an opening;
• a first phase plug, comprising:
• a cone;
• a plurality of first fins located on an outer surface of the cone;
• and
• a plurality of second fins, located on the outer surface of the cone, wherein the first fins and the second fins are arranged staggeredly, and a first gap is provided between any adjacent first fin and second fin;
• and
• a second phase plug, located under the first phase plug, and comprising:
• a round-disc base;
• a combining portion, located in the center of the round-disc base, wherein the combining portion and the cone can be combined with each other;
• and
• a plurality of second gaps, located between an outer edge of the round-disc base and the combining portion, wherein
• the first gaps are respectively aligned with the second gaps;
• a vibrating diaphragm, located under the second phase plug;
• and
• a magnetic circuit system, comprising a voice coil, wherein the magnetic circuit system can be powered on to generate electromagnetic induction, so that the voice coil generates a piston movement to vibrate the vibrating diaphragm vertically;
• and
• the housing covers the first phase plug and the second phase plug, and when the vibrating diaphragm vibrates vertically, an acoustic path is formed by the first gaps and the second gaps, so that a resultant wave is output from the opening.