Currently auditioning Tranquility Base. Didn't think it made much difference, if any, initially. It turned out a few of the active connections in the system had come off inadvertently. When I restored the connections, there was a pretty considerable difference for the better with the Base on. A fellow audiophile confirmed what heard as well.
The addition of the Base under my source is providing a noticeable improvement in both imaging and depth of soundstage. In addition, both the highs and lows are a bit more clear and defined, while at the same time managing to be more musical as well. The greatest difference is heard when I turn the Base off.
My system is pretty resolving, so I was and am surprised to hear as much of a difference as I have. I understand the premise, just didn't think it would make such a noticeable positive difference. It has so far and I have John at The Cable Company to thank for turning me on to this Base.