Calculating a doppler compensation value for a loudspeaker signal in a wavefield synthesis system

Method for calculating a plurality of loudspeaker signals for a plurality of loudspeakers, the plurality of loudspeakers comprising at least four loudspeakers, the method comprising:

• wave-field synthesis calculating, for each virtual source of a plurality of virtual sources at different virtual positions, a component signal for each loudspeaker of the plurality of loudspeakers,
• wherein each component signal for each loudspeaker and each virtual source has a discrete value for a current time of the component signal for a loudspeaker based on the virtual source,
• determining, for each virtual source and each component signal, delay information for the virtual source using position information indicating a position of the virtual source, wherein the delay information indicating by how many samples an audio signal is to occur delayed with regard to a time reference in the component signal for a loudspeaker;
• providing, for each virtual source and for each component signal for each loudspeaker, a first delay associated to a first position of the virtual source, the virtual source having the first position at a first time;
• providing a second delay associated to a second position of the virtual source, the virtual source having the second position at a second later time, wherein the second position differs from the first position and wherein the current time is between the first time and the second time;
• determining, for each virtual source and for each component signal for each loudspeaker, a first value of the audio signal for the virtual source for the current time, the audio signal for the virtual source being delayed by the first delay;
• determining, for each virtual source and for each component signal for each loudspeaker, a second value of the audio signal for the virtual source for the current time, the audio signal for the virtual source being delayed by the second delay;
• weighting, for each virtual source and for each component signal for each loudspeaker, the first value with a first weighting factor to obtain a first weighted value;
• weighting, for each virtual source and for each component signal for each loudspeaker, the second value with a second weighting factor to obtain a second weighted value;
• summing, for each virtual source and for each component signal for each loudspeaker, the first weighted value and the second weighted value to obtain the discrete value for the current time for a component signal for a loudspeaker for a virtual source;
• and
• adding, for each loudspeaker, all component signals for each virtual source for the loudspeaker to obtain the loudspeaker signal for the loudspeaker.

Digital memory media having stored thereon a computer program with a program code for performing, when running on a computer, a method for calculating a plurality of loudspeaker signals for a plurality of loudspeakers, the plurality of loudspeakers comprising at least four loudspeakers, the computer program comprising:

• program code for wave-field synthesis calculating, for each virtual source of a plurality of virtual sources at different virtual positions, a component signal for each loudspeaker of the plurality of loudspeakers,
• wherein each component signal for each loudspeaker and each virtual source has a discrete value for a current time of the component signal for a loudspeaker based on the virtual source,
• program code for determining, for each virtual source and each component signal, delay information for the virtual source using position information indicating a position of the virtual source, wherein the delay information indicates by how many samples an audio signal is to occur delayed with regard to a time reference in the component signal for a loudspeaker;
• program code for providing, for each virtual source and for each component signal for each loudspeaker, a first delay associated to a first position of the virtual source, the virtual source having the first position at a first time;
• program code for providing a second delay associated to a second position of the virtual source, the virtual source having the second position at a second later time, wherein the second position differs from the first position and wherein the current time is between the first time and the second time;
• program code for determining, for each virtual source and for each component signal for each loudspeaker, a first value of the audio signal for the virtual source for the current time, the audio signal for the virtual source being delayed by the first delay;
• program code for determining, for each virtual source and for each component signal for each loudspeaker, a second value of the audio signal for the virtual source for the current time, the audio signal for the virtual source being delayed by the second delay;
• program code for weighting, for each virtual source and for each component signal for each loudspeaker, the first value with a first weighting factor to obtain a first weighted value;
• program code for weighting, for each virtual source and for each component signal for each loudspeaker, the second value with a second weighting factor to obtain a second weighted value;
• program code for summing, for each virtual source and for each component signal for each loudspeaker, the first weighted value and the second weighted value to obtain the discrete value for the current time for a component signal for a loudspeaker for a virtual source;
• and
• program code for adding, for each loudspeaker, all component signals for each virtual source for the loudspeaker to obtain the loudspeaker signal for the loudspeaker.

Method of calculating a discrete value for a current time of a component in a loudspeaker signal for a loudspeaker based on a virtual source in a wave-field synthesis system with a wave-field synthesis module and a plurality of loudspeakers, wherein the wave-field synthesis module is formed to determine delay information by using an audio signal associated to the virtual source and by using position information indicating a position of the virtual source, indicating by how many samples the audio signal is to occur delayed with regard to a time reference in the component, wherein the audio signal is a sequence of discrete values, which are spaced apart by a sample period, comprising:

• providing a first delay associated to a first position of the virtual source, the virtual source having the first position at a first time;
• providing a second delay associated to a second position of the virtual source, the virtual source having the second position at a second later time, wherein the second position differs from the first position, wherein the current time is between the first time and the second time, and wherein the first time and the second time are spaced apart by more than the sample period;
• wherein in the steps of providing the first delay and the second delay a time distance of the first time and the second time is set in dependence on position information, so that the time distance is higher than a reference distance when the virtual source moves with less speed than a reference speed, and that the time distance is smaller than the reference distance when the virtual source moves with higher speed than the reference speed,
• determining a first value of the audio signal for the current time, the audio signal being delayed by the first delay;
• determining a second value of the audio signal for the current time, the audio signal being delayed by the second delay;
• weighting the first value with a first weighting factor to obtain a first weighted value,
• weighting the second value with a second weighting factor to obtain a second weighted value;
• and
• summing the first weighted value and the second weighted value to obtain the discrete value for the current time.

Method of calculating a discrete value for a current time of a component in a loudspeaker signal for a loudspeaker based on a virtual source in a wave-field synthesis system with a wave-field synthesis module and a plurality of loudspeakers, wherein the wave-field synthesis module is formed to determine delay information by using an audio signal associated to the virtual source and by using position information indicating a position of the virtual source, indicating by how many samples the audio signal is to occur delayed with regard to a time reference in the component, comprising:

• providing a first delay associated to a first position of the virtual source, the virtual source having the first position at a first time;
• providing a second delay associated to a second position of the virtual source, the virtual source having the second position at a second later time, wherein the second position differs from the first position and wherein the current time is between the first time and the second time, wherein a time distance between the first time and the second time is N sample periods;
• determining a first value of the audio signal for the current time, the audio signal being delayed by the first delay;
• determining a second value of the audio signal for the current time, the audio signal being delayed by the second delay;
• weighting the first value with a first weighting factor to obtain a first weighted value,
• weighting the second value with a second weighting factor to obtain a second weighted value;
• wherein in the steps of weighting the same first weighting factor and the same second weighting factor for a number of M subsequent current discrete values is used, wherein M is smaller than N and higher than or equal to 2, and
• summing the first weighted value and the second weighted value to obtain the discrete value for the current time.

Method of calculating a discrete value for a current time of a component in a loudspeaker signal for a loudspeaker based on a virtual source in a wave-field synthesis system with a wave-field synthesis module and a plurality of loudspeakers, wherein the wave-field synthesis module is formed to determine delay information by using an audio signal associated to the virtual source and by using position information indicating a position of the virtual source, indicating by how many samples the audio signal is to occur delayed with regard to a time reference in the component, comprising:

• providing a first delay associated to a first position of the virtual source, the virtual source having the first position at a first time, wherein the second delay for the second time is estimated based on one or several delays for previous times;
• providing a second delay associated to a second position of the virtual source, the virtual source having the second position at a second later time, wherein the second position differs from the first position and wherein the current time is between the first time and the second time;
• determining a first value of the audio signal for the current time, the audio signal being delayed by the first delay;
• determining a second value of the audio signal for the current time, the audio signal being delayed by the second delay;
• weighting the first value with a first weighting factor to obtain a first weighted value;
• weighting the second value with a second weighting factor to obtain a second weighted value;
• and
• summing the first weighted value and the second weighted value to obtain the discrete value for the current time.

Method of calculating a discrete value for a current time of a component in a loudspeaker signal for a loudspeaker based on a virtual source in a wave-field synthesis system with a wave-field synthesis module and a plurality of loudspeakers, wherein the wave-field synthesis module is formed to determine delay information by using an audio signal associated to the virtual source and by using position information indicating a position of the virtual source, indicating by how many samples the audio signal is to occur delayed with regard to a time reference in the component, wherein the wave-field synthesis module is formed to calculate scaling information apart from the delay information, which indicates by which scaling factor the audio signal associated to the virtual source is to be scaled, comprising:

• providing a first delay associated to a first position of the virtual source, the virtual source having the first position at a first time,
• providing a second delay associated to a second position of the virtual source, the virtual source having the second position at a second later time, wherein the second position differs from the first position and wherein the current time is between the first time and the second time;
• determining a first value of the audio signal for the current time, the audio signal being delayed by the first delay;
• determining a second value of the audio signal for the current time, the audio signal being delayed by the second delay;
• weighting the first value with a first weighting factor to obtain a first weighted value, the first weighted value being calculated as a product of the value of the component for the current time and a first scaling factor for the current time and the first weighting factor;
• weighting the second value with a second weighting factor to obtain a second weighted value, the second weighted value being calculated as a product of the value of the component for the current time, of a second scaling factor for the second time and the second weighting factor;
• and
• summing the first weighted value and the second weighted value to obtain the discrete value for the current time.