|A lot of these "smaller" speakers are likely a snap closure assembly. The front/back snap together…; rather than use screws… Have you had a look under the base/stand itself to see if there any screw visible there?|
If there are... then - ensuring you use the "correct" screwdriver head ' - you may be able to remove them and possibly the case will start to part…, or at least allow you to gently prise the front/back apart… Do NOT force anything - and if using any kind of "prying too" ideally use a plastic one.. Less likely to damage the case?
But if one hasn't seen one of these speakers in real life… it's not easy to advise more than in general?
I trawled briefly with google for a service manual - no joy; likewise any how to disassemble info - again no joy…
They are Altec Lansing (as are many of Dell speakers - rebadged to Dell). Possibly they (Altect) can help you if you contact them?