It will be a useful and aesthetically interesting feature for speakers that are playing at a non-zero volume to be represented visually in a different way than speakers in other states, especially in the new looping playback modes.
I am not sure what visual styles will ultimately feel sensible, but for now, could we bump up the fill opacity by a noticeable amount? Not sure what the default opacity value is, but if playing ones were maybe 0.7, they would appear different?