The device is very sensitive to the way you put it on the head. Different angle or velocity and you'll get different readings.
It is also very sensitive to the distance from the hoop it it at, and the device doesn't feature anything to help with that. I ended up cutting a wooden block which touches the hoop and is attached to this device with velcro.
A bit McGyverish, but look what they've done with the Tama TW200, i wasn't that far =)
While these are not a replacement for a good set of ears they can help speed up the tuning process and get you in the right ballpark with the suggested settings they give. Perfect for the novice drummer who has yet to master tuning and much better than guess work. Having the tension of the skin equal at every lug is important and this will help achieve that. Better results are achieved with a good quality drum and skin also. One feature it is missing is a spacer to keep the watch exactly 1cm from the drum rim, which the ddrum version has.
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