Hey thanks for the request!!!!
We have done a bunch of different colors the first four stabilized batches. Here's a few examples! We really have tried to provide different shades, gradients, and colors to each of the batches. After the first couple batches were quite "bright" we had requests for darker colors so we tried to do that this time around. I think once you blow the pictures of the most recent batch up, you'll see none of them are really brown, but are actually really deep color tones with darker hues. We will definitely try to provide more variance of color in the future!
Also - more about our process, we actually use 5 x 5 x 2 blocks of wood to make these, which is slightly limiting in how unnaturally bright we can make the color. I realize that with certain woods you may be able to add more resin instead of wood if there's enough voids, but I think that is more along the lines of resin filled burl instead of actual stabilized wood, and I'm not sure how stable that would be for headphone building as I haven't tried it.
I am not sure what they are doing over with the RAD headphones but they are definitely beautiful! I was under the impression they were using epoxy resin for their units but if they are using stabilized wood they are getting some really bright colors! Very cool!