A computer-implemented method, comprising: receiving an audio object comprising audio content and object metadata, the object metadata of the audio object indicating an object spatial position of the audio object to be rendered by a plurality of audio speakers in a playback environment, each audio speaker in the plurality of audio speakers being located in a respective source spatial position in a plurality of source spatial positions in the playback environment; determining, based on the object spatial position of the audio object and the plurality of source spatial positions of the plurality of audio speakers, a plurality of initial gain values for the plurality of audio speakers, each audio speaker in the plurality of audio speakers being assigned with a respective initial gain value in the plurality of initial gain values; determining a set of active audio speakers from the plurality of audio speakers, wherein each of the plurality of speakers not being an active speaker has an initial gain value below or at a threshold value, determining, based on the object spatial position of the audio object and a set of source spatial positions at which the set of active audio speakers are respectively located in the playback environment, a set of optimized non-negative gain values for the set of active audio speakers, wherein the set of optimized gain values are yielded using the initial gain values of the active speakers as input; causing the audio object at the object spatial position to be rendered with the set of optimized gain values for the set of active audio speakers, each audio speaker in the set of active audio speakers being assigned with a respective optimized gain value in the plurality of optimized gain values. receiving an audio object comprising audio content and object metadata, the object metadata of the audio object indicating an object spatial position of the audio object to be rendered by a plurality of audio speakers in a playback environment, each audio speaker in the plurality of audio speakers being located in a respective source spatial position in a plurality of source spatial positions in the playback environment; determining, based on the object spatial position of the audio object and the plurality of source spatial positions of the plurality of audio speakers, a plurality of initial gain values for the plurality of audio speakers, each audio speaker in the plurality of audio speakers being assigned with a respective initial gain value in the plurality of initial gain values; determining a set of active audio speakers from the plurality of audio speakers, wherein each of the plurality of speakers not being an active speaker has an initial gain value below or at a threshold value, determining, based on the object spatial position of the audio object and a set of source spatial positions at which the set of active audio speakers are respectively located in the playback environment, a set of optimized non-negative gain values for the set of active audio speakers, wherein the set of optimized gain values are yielded using the initial gain values of the active speakers as input; causing the audio object at the object spatial position to be rendered with the set of optimized gain values for the set of active audio speakers, each audio speaker in the set of active audio speakers being assigned with a respective optimized gain value in the plurality of optimized gain values.