Radio Lab had an interesting episode on this topic. I seem to recall that the number of people playing the Shofar to create a high enough number of decibels was in the hundreds of thousands and that the people standing in the front would have been liquefied by the soundwaves.
Basically, it was physically impossible to generate a loud enough sound using people playing shofars to knock down a bronze era wall.
A professor proposed an alternative hypothesis and suggested that the shofar players merely served as a distraction while other Israelites tunneled under the walls to undermine the structure.
Check out the episode here: http://www.radiolab.org/blogs/radiolab-blog/2010/oct/04/walls-jericho/
Basically, it was physically impossible to generate a loud enough sound using people playing shofars to knock down a bronze era wall.
A professor proposed an alternative hypothesis and suggested that the shofar players merely served as a distraction while other Israelites tunneled under the walls to undermine the structure.
Check out the episode here: http://www.radiolab.org/blogs/radiolab-blog/2010/oct/04/walls-jericho/