1518744

Information

• Patent Grant
• 1518744

• References
• Source

• Patent Number

  1,518,744

• Date Filed

  Not available

• Date Issued

  Tuesday, December 9, 1924
  100 years ago

• CPC

  • H04R3/005 - for combining the signals of two or more microphones
  • H04R1/2838 - of the bandpass type
  • H04R1/30 - Combinations of transducers with horns, e.g. with mechanical matching means
  • H04R3/12 - for distributing signals to two or more loudspeakers

• US Classifications

  • 455 - Telecommunications
  • 181 - Acoustics
  • 340 - Communications: electrical
  • 381 - Electrical audio signal processing systems and devices
  • D14 - Recording, communication, or information retrieval equipment