Perhaps a silly question, but what are the probes and what are they used for?
Not silly at all. The probes are basically just a few 1% resistors mounted inside an RCA inline connector, with some wires coming out that have alligator clips on the end. They are used for sampling electrical signals and attenuating them so they can be measured by the FIJI DSP card. You can’t put high level signals into the card, as it can be damaged by voltages over 5V peak. You can make your own probes if you want to save a few $, they are not difficult. A speaker converts electrical to acoustical energy. To really measure it correctly, you need to measure both what goes in (electrical) and what comes out (acoustical) and calculate what happens between. The mic does the acoustical pickup, the probe does the electrical pickup. Also, impedance measurements require two electrical measurements, so two probes are used to determine both voltage and current through what is being tested.
