The MCE84 works perfectly well with either the AA battery or external phantom power, and there didn't appear to be any conflict if the battery was left in when phantom power was applied. Unfortunately, the review model was not supplied with any operating instructions, and I wasn't able to establish whether external phantom power or the internal battery took precedence if both were available.

The microphone has a broad frequency response (quoted as 40Hz‑20kHz) and is claimed to be able to handle signals levels of up to 138dBA SPL. It's also claimed to have a cardioid polar response, but the large number of slots on the microphone's body would suggest a rather narrower response than that: in practice, I found the microphone had a pretty tight pick‑up pattern, more along the lines of a hyper‑ or super‑cardioid. Compared with the frontal axis, sensitivity is considerably lower at 90° incidence — maybe as much as 12dB. Like all highly directional microphones, the MCE84 suffers from handling noise and any mechanical vibrations reaching the body are quickly transferred to the capsule itself. The clip was not spectacularly good at minimising stand‑born vibrations, but was adequate for the purpose.