Minus-k and Halcyonics are comparable in vertical-isolation performance and both are superior to the Vibraplane. The Minus-k systems are passive and have resonant frequencies (0.5 Hz) that are an order of magnitude lower than pneumatic isolators. Once set up, a Minus-k table needs no maintenance. In contrast, the Halcyonics units are active and require 110 V; they are also much more expensive. The extra $$ buy you somewhat better horizontal isolation compared to Minus-k; however, it's not clear that this offers much benefit in audio applications.
I have Minus-k systems in my laboratory for an atomic-force microscope and a surface-plasmon imaging apparatus. The effectiveness of the isolators can be readily measured with those instruments. What motivated me to buy Minus-k units for the lab was the obvious sonic benefit of mounting my turntable on a Minus-k BM-8 isolator at home. In my view this remains the most cost-effective upgrade I've ever done.
I have Minus-k systems in my laboratory for an atomic-force microscope and a surface-plasmon imaging apparatus. The effectiveness of the isolators can be readily measured with those instruments. What motivated me to buy Minus-k units for the lab was the obvious sonic benefit of mounting my turntable on a Minus-k BM-8 isolator at home. In my view this remains the most cost-effective upgrade I've ever done.
