Securing speakers to speaker stands?

I plan to build some cheap speaker stands. A 2x4 in between two pieces of particle board used for shelving, and I'll just set the speaker on top. However, I'm worried about bumping and knocking them over, and am looking for ideas on how to non-permanently secure them in place. Just enough to survive a bump.

So far I'm leaning towards adhesive velcro strips. Or, screwing some small L/corner brackets into the top of the stand so that they fit the speaker nice and snug, and I'll glue some spongey foam I've got lying around on the inside of the brackets to help protect the speaker and help hold it in place even better. Brackets won't be screwed into speaker, just rely on pressure/friction.

I tend to overlook simple solutions for things. You should see the original mock up for the speaker stands....So looking for suggestions.

The speakers are roughly 5-6 lbs, and the others maybe 12-15.

 

I like the Velcro idea, which will couple the speakers to the shelves less than screws & brackets would.

 

Hot glue was my first thought.

 

4 of these per speaker or up to 8 (2 per corner). When mounting the brackets, put a business card or two between bracket and speaker to allow for easy "insertion". Pre-drill pilot holes as usual on particle board.

 

For mounting smallish plastic computer speakers, my trick is:
Create a small key-hole-mount-hole-and-slot in the base by scraping / filing away at the bottom of the speaker- don't use a drill, just scraping with a penknife is usually sufficient, only takes a minute or two.
Then simply put in a screw in the location you want the speaker to stay, set into the hole, slide onto the slot- tighten screw or add shims until you get a good friction fit.
Also works for mounting small speakers upside down UNDER a wooden shelf so they're out of the way.