Omnidirectional microphones can be considered sonically optimal if realized as true single-diaphragm systems – which is what we at SCHOEPS do. Their strengths include exceptionally linear frequency response with extended low-frequency response and a low noise floor (in the case of SCHOEPS - even as low as 11dB(A)). The various types of omni capsules differ in the amount of high-frequency boost, which compensates for the high-frequency roll-off in the diffuse field. Thus, omnidirectional microphones can be free- or diffuse-field equalised. We offer a free-field and a diffuse-field version along with two others, which lie in between.