Sony SRS-XB33 give-away quiz (Patreon)

So far I got only one response, which was wrong. It's not AKG.... 

Because of this and because it's Christmas time I would like to give the option to win this speaker to all my Patrons. Maybe I should always do Christmas giveaways open to all my Patrons, what do you think?

Send me a private message if you think you know the answer.

Good luck to everyone!

Update: Zvonimir was the first who guessed correctly. My first headphone was in fact a Sony.
I don't remember if it was the MDR-CD550 or 450 or even 350 as they had lots of similar models at that time, I must have got it around 1990 or 1991. And maybe I can still find it although the pads were completely fallen apart the last time I saw it some time ago.