I bought a pair of ADS a few years back and worked on the crossover and bass drivers. Didnt take long before I sold them. A good speaker back in the day but a far cry from current offerings. As another points out, they can be greatly improved with a bit of soldering, a few subtractions and additions. I dont think you need to buy designer parts to get a significant improvement.
Who uses ADS Speakers
I worked at ADS in The late 70s and Find they are one of the best home speakers ever.
I always loved their accuracy.