You can (hopefully) see the size 8 locks on top of the long distance holders the come from the back of the chamber.

Those need to come off, but only for the part that secures the black batteries on the top, very much right behind the speaker.

Since it is virtually impossible to remove the locks without removing the speaker, speaker needs to come off. Another four very well fitted Philips screws that need to come off around the front side of the speaker.

Please find a picture attached for the tool I found in my treasure tool chest. Brought it from Germany.. "It's because of the metric system, you know.."