I just released version 1.7.0 of node-red-contrib-sony-audio. This new version adds support for speaker settings.
As this feature is based on undocumented functions of the Sony Audio Control API and I'm not able to test it with my own Sony device, I see this feature currently as experimental und cannot guarantee that it's working properly. If you have a Sony device supporting this feature (e.g. Sony STR-DN1080) and want to try it out, please provide feedback to me. Thanks!
There were also some bugfixes compared to the last major release in this version and the former minor releases, for details, please refer to the change log.