If you were to travel through space at the speed of sound (Mach 1), the loudness of the sound would depend on the medium through which the sound is propagating. In outer space, there is no air or other medium to transmit sound waves, so you wouldn't actually hear anything. Sound requires a medium, such as air, water, or solids, to travel and reach our ears.
In the absence of a medium like air, there would be no air molecules to vibrate and transmit sound waves. As a result, even if you were traveling at the speed of sound, there would be no sound waves to reach your ears or anyone else's. You would experience silence.
It's important to note that space is a vacuum, and sound cannot travel through a vacuum. This is why astronauts use radio communication to communicate in space rather than relying on sound waves.