Update your post to include full system hardware specs and OS information.
Include PSU: make, model, wattage, age, condition.
Drives: makes, models, capacity, how full?
The link you posted seems to have some sort of problem.
Drives will make some noise no matter what as has been pointed out.
And just the fact that you noticed a change in the noises is a good indication that something may be going wrong.
Remembering that anything you do could cause further damage and data loss you must be careful.
Is the data on the drive backed up, proven recoverable, and readable?
If not, the priority should be to get backed up ASAP.
Make and model drive? Capacity/how full?
Go to the applicable drive manufacturer's website and download the manufacturer's disk drive diagnostic software.
Run the diagnostic software to determine what problems may exist.
Again, with a potentially failing drive, anything you do could cause immediate failure.