If the speed of the source of sound equals the speed of sound, and the speed of the source increases with the speed of sound, it would result in a phenomenon known as sonic boom.
A sonic boom occurs when an object travels through the air at or above the speed of sound. As the object moves, it emits sound waves that propagate away from it at the speed of sound. However, since the object itself is traveling at the same speed as the sound waves it creates, the sound waves are not able to propagate ahead of the object. Instead, they pile up in a cone-shaped region known as a shock wave.
When the object surpasses the speed of sound, the shock wave moves continuously behind it. The abrupt transition from the compressed region of high-pressure air to the surrounding air creates a loud, explosive sound wave that is heard as a sonic boom.
In summary, if the speed of the source of sound equals the speed of sound and the speed of the source increases with the speed of sound, it would result in a continuous production of sonic booms as the source continues to move faster than the speed of sound.