Acoustic astrometry with a VLBI-like interferometer

We show how loud-speakers, home digital recorders, and a common personal computer can be used to emulate VLBI observations on a small scale. These audio-VLBI observations allow for single-field astrometry (sources within the same interferometric field), differential group-delay astrometry, etc. These experiments can be set up very easily and in many possible configurations. Students may find these experiments very useful to learn about the innermost details of the interferometric technique.