Generating audio driving signals for the production of simultaneous stereo sound stages

A method of generating audio driving signals based on a two-channel stereo audio signal, for use in driving upward-firing transducers, the method comprising the steps of:

• receiving a two-channel stereo audio signal;
• generating a left audio signal LA(t), a right audio signal RA (t), and a centre audio CA(t) signal based on the two-channel stereo audio signal, wherein the left and right audio signals are not positively correlated;
• generating a first audio signal S1(t) and a second audio signal S2(t) based on the left and right audio signals, wherein the first audio signal and the second audio signal are generated according to:
• S1(t)=RA (t)−LA(t−ΔtLR) and S2(t)=LA(t)−RA (t−ΔtLR), where ΔtLR is a time delay for the left and right audio signals;
• providing a left audio driving signal LD(t) for driving an upward-firing left transducer, wherein the left audio driving signal is derived from the first audio signal;
• providing a right audio driving signal RD(t) for driving an upward-firing right transducer, wherein the right audio driving signal is derived from the second audio signal;
• and
• providing a centre audio driving signal CD(t) for driving an upward-firing centre transducer, wherein the centre audio driving signal is derived from the centre audio signal.

An audio system comprising one or more digital signal processors adapted to perform a method of generating audio driving signals based on a two-channel stereo audio signal, for use in driving upward-firing transducers, the method comprising the steps of:

• receiving a two-channel stereo audio signal;
• generating a left audio signal LA(t), a right audio signal RA (t), and a centre audio CA(t) signal based on the two-channel stereo audio signal, wherein the left and right audio signals are not positively correlated;
• generating a first audio signal S1(t) and a second audio signal S2(t) based on the left and right audio signals, wherein the first audio signal and the second audio signal are generated according to:
• S1(t)=RA (t)−LA(t−ΔtLR) and S2(t)=LA(t)−RA (t−ΔtLR), where ΔtLR is a time delay for the left and right audio signals;
• providing a left audio driving signal LD(t) for driving an upward-firing left transducer, wherein the left audio signal is derived from a summation of the first audio signal and the centre audio signal;
• and
• providing a right audio driving signal RD(t) for driving an upward-firing right transducer, wherein the right audio signal is derived from a summation of the second audio signal and the centre audio signal.