It will probably depend to some extent on the speaker and how it is designed. A true anechoic chamber would be highly unpleasant to occupy in silence [Link]. I suspect that it wouldn’t seem great for music playing, at least not with most speakers, and if playing quietly the lack of normal room ambience would likely intrude. However, getting close to anechoic, in effect removing the room, can be highly beneficial, as I found and reported in another thread, linking early in this one but tge key part copied here for convenience: