<HTML>Hello list, I'm just as disgusted as you are when I see these rods used without humidistats. I view this as malpractice. It takes almost a full year to straiten out the piano problems as a result of this practice. As far as an independent study, the only thing I can tell you is I've installed hundreds of these fine systems and I've been impressed with the results.Some of my pleasure with the system is very selfish though. I tune pianos in the midwest where we experience intense swings in humidity. Also, about seventy percent of my tuning business is at six months intervals. In the real world this means we're doing minor pitch corrections seventy percent of the time. Not only does this lead to tuning instability, but I used to come home very sore all the time. If it takes an extra fifteen minutes to do a minor pitch correction times six appointments a day, the stress on your body is tremendous. As the percentage of my clients with DC systems increased, I noticed a huge difference in the quality of the tuning stability and the enjoyment of my craft. I guess this makes me a proponent. Bob Russell RPT</HTML>