Dynamic equalizing of powered loudspeaker systems

• US 5,361,381 A
• Filed: 12/17/1993
• Issued: 11/01/1994
• Est. Priority Date: 10/23/1990
• Status: Expired due to Term

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Short, William R.
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): TONG, NINA C
• Application Number:
  US08/169,713
• Time in Patent Office: 319 Days
• Field of Search: 381/98, 381/103, 381/79, 381/102, 381/101, 381/24, 381/99, 381/100, 381/111, 381/120
• US Class Current: 381/80
• CPC Class Codes: H04R 29/001 for loudspeakers H04R29/007 takes precedence
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S

Abstract

A powered loudspeaker system has a cabinet. The cabinet has at least one electroacoustical transducer and a power amplifier coupled to the electroacoustical transducer. Dynamic equalization circuitry coupled to the power amplifier provides a predetermined desired dynamic equalization for the electroacoustical transducer in the cabinet when normally positioned in a listening room.

Claims

1. A loudspeaker system comprising

a base unit having a volume control circuit and comprising means for transmitting an audio channel signal of level controlled by said volume control circuit, and

a powered speaker having a cabinet with said powered speaker including said cabinet being remote from said base unit with at least an electroacoustical transducer and power amplifier supported by said cabinet and further comprising,

means supported by said cabinet for receiving said transmitted audio channel signal,

a direct signal processing path supported by said cabinet producing a direct path output signal and a side signal processing path supported by said cabinet producing a side path output signal,

said side signal processing path comprising a variable attenuator responsive to said received audio channel signal to produce a variably attenuated signal, and a low-pass filter responsive to said variably attenuated signal to produce said side path output signal,

means supported by said cabinet for combining said direct and side path output signals to produce a processed audio signal, and

said electroacoustical transducer responsive to said processed audio signal to generate audible sound,

whereby the low frequency components of said audio channel signal are boosted such that, when said processed audio signal is generated at low audible sound levels, listeners have improved perception of the bass spectral components of said audio channel signal.

2. The loudspeaker system of claim 1, wherein

said transmitting means further comprises means for transmitting multiple audio channel signals,

said receiving means further comprises means for receiving multiple audio channel signals, and

said side signal processing path further comprises a combiner responsive to said multiple received audio channel signals to produce a combined signal, wherein said variable attenuator is responsive to said combined signal.

3. The loudspeaker system of claim 2, wherein said filter produces a filtered signal having substantially reduced content in the frequencies above 200 Hz.

4. The loudspeaker system of claim 1, wherein

said transmission means comprises a radio frequency modulator, and

said receiving means comprises a radio frequency demodulator.

5. The loudspeaker system of claim 1, wherein

said transmission means comprises an infrared light emitting device, and

said receiving means comprises an infrared light sensitive device.

6. The loudspeaker system of claim 1, wherein

said transmission means comprises an ultrasonic radiator, and

said receiving means comprises an ultrasonic detector.

7. The loudspeaker system of claim 1, wherein said means for transmitting and

said means for receiving comprises low-power speaker wires.

8. The loudspeaker system of claim 1, wherein said base unit further comprises

a volume control signal generator responsive to user input to produce a volume control signal, and

a channel signal attenuator responsive to said volume control signal to vary the gain of said audio channel signal prior to transmission.

9. The loudspeaker system of claim 8 wherein said variable attenuator comprises a compressor having a gain inversely proportional to the level of said received audio channel signal.

10. The loudspeaker system of claim 9 wherein

said direct signal processing path comprises a low-pass crossover filter responsive to said received audio channel signal to produce said direct path output signal, and further comprising

a second powered speaker comprising

second means for receiving said transmitted audio channel signal,

a high-pass crossover filter responsive to the audio channel signal received by said second receiving means to produce an upper frequency signal, and

an upper frequency transducer responsive to said upper frequency signal to generate audible sound.

11. The loudspeaker system of claim 1 wherein

said base unit further comprises a volume control signal generator responsive to user input to produce a volume control signal, and said transmitting means further comprises means for transmitting said volume control signal, and

said receiving means further comprises means for receiving said volume control signal.

12. The loudspeaker system of claim 11 wherein

said variable attenuator is responsive to said received volume control signal to control the gain of said variably attenuated signal.

13. The loudspeaker system of claim 12 wherein

said base unit further comprises a channel signal attenuator responsive to said volume control signal to vary the gain of said audio channel signal prior to transmission.

14. The loudspeaker system of claim 13 wherein

said direct signal processing path comprises a low-pass crossover filter responsive to said received audio channel signal to produce said direct path output signal, and further comprising

a second powered speaker comprising

second means for receiving said transmitted audio channel signal,

a high-pass crossover filter responsive to the audio channel signal received by said second receiving means to produce an upper frequency signal, and

an upper frequency transducer responsive to said upper frequency signal to generate audible sound.

15. The loudspeaker system of claim 12 wherein

said direct path comprises a channel signal attenuator responsive to said received volume control signal to control the gain of said direct path output signal.

16. The loudspeaker system of claim 1 wherein

said direct signal processing path further comprises a low-pass crossover filter to reduce the upper frequency content of said direct path output signal, and further comprising

a second powered speaker comprising

second means for receiving said transmitted audio channel signal and said volume control signal,

a high-pass crossover filter responsive to the audio channel signal received by said second receiving means to produce an upper frequency signal,

a second channel signal attenuator responsive to the volume control signal received by said second receiving means to control the gain of said upper frequency signal, and

an upper frequency transducer responsive to the output of said second channel signal attenuator to generate audible sound.

17. A powered loudspeaker system comprising,

a cabinet,

said cabinet having at least one electroacoustical transducer and a power amplifier coupled to said electroacoustical transducer,

and dynamic equalization circuitry having an audio channel input for receiving an audio channel signal supported by said cabinet and coupled to said power amplifier having circuit parameters for establishing a predetermined desired dynamic equalization for said electroacoustical transducer and circuitry constructed and arranged to receive control signals from a location remote from the location of said cabinet in said cabinet when normally positioned in a listening room,

said electroacoustical transducer responsive to a processed audio signal coupled from said audio channel input through said dynamic equalization circuitry and said power amplifier to generate audible sound,

whereby low frequency Components of an audio signal applied to said audio channel input are boosted such that, when said processed audio signal is generated at low audible sound levels, listeners have improved perception of the bass spectral components of the audio channel signal applied to said audio channel input.