The ornamental design for a speakerbox, as shown and described.
1.-2. Speaker box
1.1 : Front
1.2 : Back
1.3 : Left
1.4 : Bottom
1.5 :Top
1.6 : Perspective
1.7 : Perspective
2.1 : Front
2.2 : Back
2.3 : Left
2.4 : Bottom
2.5 : Top
2.6 : Perspective
2.7 : Perspective
Figs. 1.1-1.7 show an embodiment of speaker box; and figs. 2.1-2.7 show another embodiment of speaker box; the product relates to a smart speaker used for audio play and can receive voice commands for human-computer interaction, such as obtaining networking information or controlling other networked electronic devices.