CD seems to be the most universal format. Many won't play flash drives for fear of viruses and such. Or just not knowing how to play them.I have a question for the technical brains: what format is best to take to hear familiar music if they will let you play it? CD? FAT32 USB chips in FLAC? What form and formats? What are guys transporting their music on these days?
Since flash drivers are small anyway, if you want to be fully covered, take that too. But as your vinyl experience, expect some to not want to play anything you bring.
I learned that just using one track was more revealing than a bunch. You get a lot more calibrated with that, than playing multiple tracks.
As a courtesy to others in the room, please don't ask them to play a full album as some do. I have suffered to death listening to someone's entire album as the exhibitor is too polite to stop them. It is as if they want to show off their taste in music, not realizing the rest of us are not there to listen to their music but to evaluate the gear and move on to the next room.