Picked up a handful of electret microphones from a local component store, and store owner claims them to be generic. He calls all components generic for which there is no data-sheet or specific part number.
Wondering, if there is any way to determine if these are uni-directional mics, or omni-directional ones ? Doing some search to see if there are any distinguishing physical characteristics, I came across pictures almost the same, just that few seem to have 3 leads, and most have 2 leads.
Edit:
This is an alternate approach I am trying, by replacing the electret microphone that came with an el-cheapo baby-monitor, which is definitely omni-directional, and currently results in pretty terrible howling, when the 2-way talk feature is activated. The other approach is in-discussion (as some might have seen/noticed) in this question.
Best Answer
In terms of actual directionality, you'll probably just have to test them by measuring the response to a source at different angles. Normally this would be done in an anechoic chamber, but you might be able to accomplish something by supporting the microphone on a post well off the ground in the center of a large carpeted room and walking around it with the source, or outside on a calm day. You could tie a string to the post to measure a consistent radial test distance.
Directionality will probably be somewhat different at extremes of frequency.
Since your source probably wouldn't be omni-directional, try to be consistent for example always aiming it at the microphone.