A ribbon mic would be a very welcome addition to my collection, but would its figure-of-eight pattern mean I pick up more of the (poor!) room tone compared with a cardioid condenser?
SOS Forum post
Technical Editor Hugh Robjohns replies: Believe it or not, the amount of room pickup is actually exactly the same for a figure-of-eight (figure-8) mic as for a cardioid one: both figure-8 and cardioid mics have a ‘Distance Factor’ of 1.7. It’s only the directions of maximum pickup and attenuation that are different — that obviously matters if you’re trying to reject spill from somewhere specific, but it doesn’t if it’s just ambient room noise that you want to reduce.
The Distance Factor is the distance from a source at which the mic can be positioned to give the same ratio of direct wanted source sound to ambient room sound as an omni-pattern mic. In other words, imagine where you would need to place an omni for a given ratio of direct to ambient sound, and a cardioid or figure-8 can be placed 1.7 times further away from the source for exactly the same sound balance. Alternatively, if the cardioid or figure-8 mic is placed in the same place as the omni, they will capture less room sound in the same proportion. For reference, the Distance Factors for supercardioid and hypercardioid patterns are 1.9 and 2 respectively, and a shotgun/rifle mic would manage somewhere between 3 and 6, depending on the length of the interference tube and the mic’s design.