The IE‑45 can serve as a polarity checker for acoustic and electronic devices. 

The IE‑45 (or the CD that comes with an IE‑45 purchase) can generate a pulse which can be applied to a sound system to excite speakers. By then placing the IE‑45 in the direct field of the speaker (or, directly on axis if not in the direct field), it can determine whether the speaker is wired in or out of polarity.

The Polarity display gives a very clear indication as to the polarity of the speaker in both color graphic and text form. When the Polarity function is “locked on” the signal, the display will either be a large + or ‑. If there is no “signal lock,” the display turns to dashes ( ‑ ‑ ).