Polyphony and monophony in instruments harpejji and the Chapman stick). Multiphonics can be used with many regular wind instruments to produce two or more notes at once, although this is considered an extended technique. Explicitly polyphonic wind instruments are relatively rare, but do exist. The standard harmonica can easily produce several notes at once. Multichambered ocarinas are manufactured in a number of varieties, including double, triple, and quadruple ocarinas, which use multiple chambers to extend the ocarina's otherwise limited range, but also enable the musician to play more than one note simultaneously. Harmonic ocarinas are specifically designed for polyphony, and in these instruments the range
Owned-and-operated television stations in the United States owned KTLA (channel 5) in Los Angeles and WBKB (channel 4, now WBBM-TV on channel 2) in Chicago, owned a share of the network. However, the FCC declared that Paramount controlled DuMont and thus forbade the network and the studio from acquiring any more stations. This was one of the factors that led to DuMont shutting down in August 1956. For much of the era from 1958 to 1986, the major network-owned stations were distributed as follows: ABC, CBS and NBC each owned stations in the top three markets (New York City, Los Angeles and Chicago). Between 1958 and 1965,