Black Diamond Cones for speakers?

will the BDR cones work for speakers? I am considering them as they do not look like they will scratch floors
Yes they work well under speakers too. Crush weight on each cone is 10000lbs. They look blunt on the tip but if you have a heavy speaker and you drag the cones under it, it will still leave marks on the floor.
I use 'em on my KEF's and they seem to help a bit. Look real nice too as they screw right into the brass footer and spike.

Be sure to use the #4 cones as they are for heavier components. I agree with the first poster that they can still mark the floor -- although it's negligible compared to what spikes do.
It only help if you use The Pit under the Cones for speakers application, otherwise, the speaker will move by itself and you lose a lot of the bass.
You are going to have to trust your ears. I used BDR's under my kestral hotrods and they were not at all compatable. It may have been the combo of my parquet over concrete slab floor with the cones but what I ended up with was an annoying upper midrange exaggeration and a thinning out of midbass - not fun! It's too bad as they threaded perfectly into my speaker. Went to a vibropod-like material and was much happier. YMMV.