*chirp* or *clunk* don't matter, this is what matters :
( copied from
ngohq.com )
..... According to an in-house investigation and
user reports', some software and operating systems are incompatible with the Intellipark feature causing endless head parking movement as the HDD continuously goes in/out of idle mode. This abnormal behavior creates stress on the HDD and that could lead to the following issues:
• Loud clunking/clicking/buzzing noises every few seconds.
• Artificially increases the number of load-unload cycles in S.M.A.R.T.
• Possibly shortens life-time of the HDD.
• Possibly reduces performance of the HDD.
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The behaviour you mentioned - accessing the drive after sometime causing clunk - is very much the same as WD's drives with Intellipark, in which the heads park after a mere 8 seconds causing unnecessary parking/unparking of the heads.