<p>Hmmm...</p><p>Good question. I'm actually not to familiar with the subject. My first guess would be: No. I don't believe a pressure change in the medium under typical conditions can exceed the speed of sound in that medium. Why? Because sound really is just a moving pressure front by itself.</p><p> </p><p>Granted, there are cases where a pressure front exceeds the speed of sound in the medium, but they're rather extreme. Atomic blast shockwaves for instance. </p> <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>