I have not purchased any "new" equipment in decades. Back then my speaker break-in was done out of the box, connected to an old receiver in a closet. Speakers place face to face with one speaker hooked in reverse polarity. Receiver set to an FM music station, Mono mode and ran a bit higher than my regular listening setting. After a couple days, I reverse the speaker polarities. And run them another couple of days. Reset the connections to proper polarities and in Stereo Mode another few days. Took a few days to a week, but never was disappointed because of "break-in".