"If it’s in free space, sound will be dispersed equally around the speaker, but if it’s close to a back wall the HomePod will actively split out some of the more ambient elements of your music and bounce them off the rear surface while projecting the vocals and more direct sounds straight into the room."

Read more at https://www.whathifi.com/apple/homepod/review#14Ajr6HVQVVwpWji.99"

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated