As long as there is no magnetic storage (hard drives, floppies, etc), you're not likely to cause any permanent damage... Almost all networking gear these days runs entirely off of solid state components and flash/nvram storage.
It is remotely possible that EMI/RFI from the speaker could get into the network gear and cause issues, but most gear is built to tolerate noisy environments (server farms are full of noisy motors). If that happens, just move the speaker (and possibly reboot the network gear) and all should be good again.