The “overheads” on a drum set refer to the microphone(s) that are suspended above the drums in order to capture the entire kit. While you can use one or several microphones to record this, it’s most common to see a matched pair of microphones which can be panned right and left, giving you a nice and wide sound.
The most popular configurations for this are the Spaced Pair and X/Y configurations, and each give you slightly different pros and cons. A spaced pair configuration puts one microphone on each side of the drum set, and as such, gives a wider sound. The XY setup instead places the microphones in the above middle of the drums, with the two microphones angled towards opposite sides of the drums. Although resulting in a more narrow stereo image, this works great when being listened to in mono, as there is less differentiation between what each microphone is picking up.
While there are plenty of other ways to place overhead microphones such as Mid/Side, ORTF, and the Glyn Johns method, the spaced pair and XY configurations are the most commonly used, and provide a great representation of the overall drum set’s sound.
I’ve recorded a video featuring both these configurations, as well as a hybrid of the two, so give this a listen to hear the differences for yourself, and let me know what you think!