Saw Johan uploaded this recently and it was really interesting. Exact same cab but one with the older style plywood back and the other with the more common mdf back. I've really been appreciating how different the same speakers can sound in different cabinets (and also how that'll load the amp differently and affect the amps negative feedback), but this was a cool test to show how changing JUST the back can alter things quite noticeably. Johan's channel is a pretty amazing resource of information, and never with any bullshit/opinion. Well researched and fairly tested.