Critical to all R&D is comparing results to [**specifications.**][1]

If you can manage to verify the table of every spec, starting from voltage , current, etc  .. All the way down in a checklist. Then draw a thumbnail scope reading of each pin using short gnd leads on 1 page and then compare with spec...

Be wary that the chip uses a ramped voltage controlled gain to compensate for attenuation versus time delay due to inverse squared loss.  You can verify he gain by "back driving" from another speaker + generator at a very low level to determine the threshold of gain without having to rig echoes at different distances.

Then, you should be able to pinpoint the issue or at least ask a better question!!


  [1]: http://www.prowave.com.tw/pdf/sonaric.pdf