If Rick Rubin could take a tape to his car to listen to his mixes, your product people can try their websites on £20 phones from Tesco. They can ask to sit in on user tests with minority groups. Extending your knowledge like this is trivial, but rarely done.

May i ask why, specifically, Rick Rubin? I don't know who that is, but whenever we finished mastering a new song, we had a series of "systems" we listened to it on. We went out to my dad's work van and listened there. We called up our friend with a street-comp sound system in his car, and listened in there (neighbors must have loved us!), and then a "cheap" boombox with large-ish speakers but cheap.

if it sounded "clean" on all 3, without the bass muffling everything, and the highs not hurting the eardrums, we called it "good" and released.

Yeah but for those not using £20 phones from Tesco, where is the disrespect?