| 摘要 |
1385346 Loud-speaker systems; local circuits SABA SCHWARZWALDER APPARATEBAU - ANSTALT AUGUST SCHWER SOHNE GmbH 7 Dec 1972 [19 Jan 1972] 56598/72 Heading H4J A hermetically sealed cabinet contains one high frequency tweeter or medium high frequency loud-speaker 4 and at least two identical low frequency speakers 2, 3 which are fed via separate filters 7, 8 and 9, 10 respectively, the high frequency cut-off frequency, f 1 , of one of the filters being at least an octave lower than that, f 0 , of the other. The high frequency roll off of both filters is 12dB/octave. A third identical low frequency speaker may be introduced which is associated with a filter having a 12dB/octave roll off at a frequency at least one octave lower than f 1 . More than one speaker may be associated with the same filter. |
