Sound enhancement system
OwnerThomas Nelson Packardinventor
Life of this patent
Estimating the term…
Abstract
A system for enhancing sound quality comprising a filter that square roots the instantaneous amplitude of frequencies in an input signal for generating artificial harmonics corresponding to said frequencies. The system can comprise an automatic level control that momentarily boosts the amplitude of artificially generated harmonics to emphasize attack transients occuring within the input signal.
Claims29
A system for enhancing sound quality, comprising an input terminal for receiving an input signal, a first filter that receives signal from the input terminal that blocks frequencies below a certain predetermined frequency;
- a complementary filter that receives signal from the input terminal, a square root filter coupled to the first filter, the circuit being configured to determine a square root of an input signal portion on a continual basis;
- and a differentiator whose gain increases with increasing frequency connected between said first filter and said square root filter, a summer with one input to receive signal from said complementary filter and a second input to receive signal from the square root filter and that has an output connected to an output terminal;
- an integrator connected between said square root filter and said one input of said summer, whereby the output signal at said output terminal is the sum of square root signal for input signals above the predetermined frequency, plus input signal for all other frequencies blocked by the first filter, and wherein when signal from said first filter comprises low frequency and high frequency signals greater than said pre-determined frequency and having similar amplitudes, said square root filter receives a relatively greater amplitude of said high frequency signal from said differentiator and is predisposed to produce artificial overtones from said high frequency, and wherein said integrator provides an inverse gain versus frequency relationship to said differentiator.
A system for enhancing sound quality comprising an input terminal for receiving an input signal, an output terminal for sending an output signal, a first filter that receives signals of all frequencies from the input terminal and that passes signals in a predetermined range of frequencies, a complementary filter that receives signal from the input terminal, an automatic volume control that receives signal from said first filter, a non-linear filter that receives signal from the automatic volume control and produces artificial overtones commensurate with the signal from said first filter, a summer that sums signals from the non-linear filter and the complementary filter and having an output connected to said output terminal;
- an inverse automatic volume control connected between said non-linear filter and the summer whose gain is the inverse of the automatic volume control, wherein the amplitude of the signal from the inverse automatic volume control proportionally tracks the amplitude of the signal from the first filter;
- wherein the output signal contains artificial overtones for input signals within the range of frequencies passed by said first filter at a pre-established constant amplitude, plus input signals devoid of artificial overtones for other input signals exclusive of frequencies passed by said first filter.
A system for enhancing monaural input signal comprising
- a plurality of loudspeakers or recording channels for reproduction of signal, at least one device each having an input terminal for receiving the monaural input signal, a square root filter to determine a square root of the input signal portion to generate artificial high frequency overtones from the portion of the input signal, and an output terminal for providing signal from the square root filter, each device as part of said system further comprising an automatic volume control connected between said input terminal and square root filter, an inverse automatic volume control connected between said square root filter and output terminal, and a transient attack detector that increases the gain of the inverse automatic volume control upon detection of a transient;
- wherein a loudspeaker or recording channel is coupled to receive signal from said output terminal and another loudspeaker or recording channel is coupled to receive signal from either another of said output terminal or said input terminal to create a pseudo-stereo effect.
A system for enhancing multi-channel input signals comprising
- a plurality of loudspeakers or recording channels for reproduction of signal,
- at least one device each having an input terminal for receiving at least one of the input signals, a square root filter that takes the square root of a portion of the at least one signal at the input terminal to generate artificial high frequency overtones from the at least one input signal at the input terminal, and an output terminal that receives signal from the square root filter and that provides an output signal, an automatic volume control connected between said input terminal and square root filter, each device as a part of said system further comprising an inverse automatic volume control connected between said square root filter and output terminal, and a transient attack detector that increases the gain of the inverse automatic volume control upon detection of a transient;
- wherein said output signal is provided to one or more loudspeaker or recording channel to enhance the stereo imagery of the input signals thereby.
Dependencies are inferred from the claim text.