Audio signal processor providing simulated source distance control

Audio signal processing system including signal processing means responsive to an input signal that is from a control means;

• means for modifying a sound source signal S from a sound source so as to simulate said sound source at a perceived distance d.sub.S ;
• and visual display means arranged to display an image or icon, the apparent distance of said image or icon also being responsive to said control means and varying depending on said distance d.sub.S, whereby the perceived distance of the sound source and the apparent distance of said image or icon correspond;
• said signal processing means comprising:
• input means for receiving the input signal;
• output mixing means for producing an output signal;
• early reflection simulation means;
• a first signal path connecting said input means to said output mixing means;
• a second signal path connecting said input means to an input of said early reflection simulation means and connecting an output of said early reflection simulation means to said output mixing means;
• and
• signal modifying means provided in one of said first and second signal paths and arranged to modify one of gain magnitude and time delay of a signal in said signal path;
• said early reflection simulation means producing, for each input signal S from said input means, a multiplicity of delayed replicas of said input signal each having a time delay T relative to an arrival time via said first signal path of said input signal S at said output mixing means, and having a gain magnitude g.sub.S relative to a gain via said first signal path of said input signal S at said output mixing means;
• and
• said signal modifying means producing modified gain magnitudes g.sub.S ' and time delays T' to produce a simulated distance d.sub.S ', said early reflection simulation means and said signal modifying means having in combination a gain/delay characteristic varying with a parameter d.sub.S corresponding to the simulated sound source distance, said gain/delay characteristic characterized by the following equation:
• g.sub.S '/g.sub.S =(e.sup.-r't'+gt)(1+cT/d.sub.S)/(1+cT'/d.sub.S ')
• where c is the speed of sound in air and r and r' are a predetermined respective original and final constants of absorption per unit time delay and both the original and final constants are one of frequency dependent and frequency independent.

An audio signal processing system for processing input signals and outputting an audio output signal giving a simulated distance effect comprising:

• input means for receiving the input signals;
• output mixing means for producing the output signal;
• early reflection simulation
• a first signal path connecting said input means to said output mixing means;
• a second signal path connecting said input means to an input of said early reflection simulation means and connecting an output of said early reflection simulation means to said output mixing means;
• and
• signal modifying means provided in one of said first and second signal paths and arranged to modify one of gain magnitude and time delay of signals in said signal path, thereby modifying a simulated distance parameter d.sub.S ;
• said early reflection simulation means producing, for each of a plurality of the input signals S from said input means, including an input signal S encoded for reproduction from a non-channel direction, a multiplicity of delayed replicas of said input signal each having a time delay T relative to the arrival time of a component of the input signal corresponding to a first arrival of said input signal at said output mixing means, having a gain magnitude g.sub.S relative to gain of said component corresponding to a first arrival of said input signal at said output mixing means, said early reflection simulation means having a gain/delay characteristic varying with said parameter d.sub.S corresponding to a simulated sound source distance, said gain/delay characteristic characterized by the following equation:
• g.sub.s =[1/(1+cT/d.sub.S)]e.sup.-rT,
• where c is the speed of sound in air, and r is a predetermined constant of absorption per unit time delay which is one of frequency dependent and frequency independent.

A sound mixing system comprising first input means for receiving a plurality of input signals from a plurality of sources, first control means, panning means responsive to said first control means for modifying an input signal received through said first input means from one of the plurality of sources to a desired stereophonic representation, second control means, and distance simulation means responsive to said second control means to further modify said input signal processed by said panning means by producing a signal with simulated reflections characteristic of a desired simulated distance, wherein said distance simulation means comprises:

• second input means for receiving the input signal from said panning means;
• output mixing means for producing an output signal;
• early reflection simulation means;
• a first signal path connecting said second input means to said output mixing means;
• a second signal path connecting said input means to an input of said early reflection simulation means and connecting an output of said early reflection simulation means to said output mixing means;
• and
• signal modifying means provided in one of said first and second signal paths and arranged to modify one of gain magnitude and time delay of signals in said signal path, thereby modifying a simulated distance parameter d.sub.S ;
• said early reflection simulation means producing for each of the plurality of input signals S a multiplicity of delayed replicas of said input signal each having a time delay T relative to an arrival time via said first signal path of said input signal S to said output mixing means, and having a gain magnitude g.sub.S relative to gain via said first signal path of said input signal S at said output mixing means, said early reflection simulation means and said signal modifying means having in combination a gain/delay characteristic varying with the parameter d.sub.S corresponding to a simulated sound source distance, said gain/delay characteristic characterized by the following equation;
• g.sub.s =[1/(1+cT/d.sub.S)]e.sup.-rT,
• where c is the speed of sound in air, and r is a predetermined constant of absorption per unit time delay which is one of frequency dependent and frequency independent.

Audio signal processing system for processing input signals and outputting audio signals giving a simulated distance effect, comprising:

• control means;
• input means for receiving the input signals;
• output mixing means for producing an output signal;
• early reflection simulation means responsive to said control means;
• a first signal path connecting said input means to said output mixing means;
• a second signal path connecting said input means to an input of said early reflection simulation means and connecting an output of said early reflection simulation means to said output mixing means;
• and
• signal modifying means responsive to said control means, said signal modifying means provided in one of said first and second signal paths and arranged to modify one of gain magnitude and time delays of signals in said signal paths,
• said early reflection simulation means producing for each of the input signals S a multiplicity of delayed replicas of said input signal each having a time delay T relative to an arrival time via said first signal path of said input signal S to said output mixing means, and having a gain magnitude g.sub.S, relative to a gain via said first signal path of said input signal S at said outside mixing means, and
• said signal modifying means producing modified gain magnitudes g.sub.S ' and time delays T' to produce a modified simulated distance d.sub.S ', said early reflection simulation means and said signal modifying means having in combination a gain/delay characteristic varying with a parameter d.sub.S corresponding to a simulated sound source distance, said gain/delay characteristic characterized by the following equation:
• g.sub.s '/g.sub.s =(e.sup.-r't'+rt)(1+cT/d.sub.S)/(1+cT'/d.sub.S ')
• where c is the speed of sound in air and r and r' are a predetermined respective original and final constants of absorption per unit time delay and both the original and final constants are one of frequency dependent and frequency.

Audio signal processing system for processing input signals and outputting,an audio signal giving a simulated distance effect, comprising:

• input means for receiving the input signals;
• output miming means for producing an output signal;
• early reflection simulation means;
• a first signal path connecting said input means to said output mixing means;
• a second signal path connecting said input means to an input of said early reflection simulation means and connecting an output of said early reflection simulation means to said output mixing means;
• and
• signal modifying means provided in one of said first and second signal paths and arranged to modify one of gain magnitude and time delays of signals in said signal path,
• said early reflection simulation means producing, for each of a plurality of input signals S from said input means, a multiplicity of delayed replicas of said input signal each having a time delay T relative to an arrival time via said first signal path of said input signal S at said output miming means, and having a gain magnitude g.sub.S relative to a gain via said first signal path of said input signal S at said output mixing means, and
• said signal modifying means producing modified gain magnitudes g.sub.S ' and time delays T' to produce a modified simulated distance d.sub.S ', said early reflection simulation means and said signal modifying means having in combination a gain/delay characteristic varying with a parameter d.sub.S corresponding to a simulated sound source distance, said gain/delay characteristic characterized by the following equation:
• g.sub.s '/g.sub.s =(e.sup.-r'(t'-t) (1+cT/d.sub.S)/(1+cT'/d.sub.S ')
• where c is the speed of sound in air and r is a predetermined constant of absorption per unit time delay and r' is a predetermined constant of absorption per unit time delay and is one of frequency dependent and frequency of independent.