by Bongo Boy » Sat Jan 26, 2002 1:40 am
I see this thread is ancient, but I'll add my observations because I like to. I have a materials engineering background, so this analytical crap may appeal to somebody.
When you tune up your drum after a 'rest' of the heads, say for a day or more, notice how much you've turned the lugs. Let's say it's a full turn (360 deg turns on all lugs). Let's also say you leave them there for 2-3 days.
First, over this period, you'll probably have added in an 1/8 turn on the lugs to get the head up to snuff on tone. So THAT alone should tell you what's happening to the head.
Second, if after 2-3 days you relax (detune) the head, then come back later an tune to the same pitch you had before, you should also notice it now doesn't take a full turn to get back to the same tuning you had previously!!!
The conclusion: natural skin heads continue to stretch out when left under tension, and when allowed to relax for a few days, will shrink. Lots of materials do this--actually, as far as I know, ALL materials do this--it's called 'creep'. But in the case of synthetics, it probably takes so long and is so small an effect, folks don't notice it much. I don't know that--I've never used a synthetic head.