Click here to purchase the entire book in PDF format. Near-coincident techniques Coincident microphone techniques rely solely on interchannel amplitude differences to produce the desired imaging effects. Spaced techniques, in theory, produce only interchannel time differences. There is, however, a hybrid group of techniques that produce both interchannel amplitude and time of arrival differences. These are known as near-coincident techniques, using a pair of directional microphones with a small separation.