I have had two a new drakes (elongated - one ADA and one regular heght), for three months now and cannot get used to the loud noise when you flush it. The noise lasts only 1-2 seconds at the start of the flush, sort of a muted shot gun bang. Then the fill is very quiet. Other than this, no problems.
Is this noise normal? Any suggestions on how to reduce the noise?
I'd have to say, that is the way they work. Older toilets dumped huge amounts of water, slowly, into the bowl, then when a critical mass occured, it swirled out of the bowl, down the drain, usually gulping a little at the end. New toilets do not have that luxury - they need to move the stuff down the drain with much less water...that takes some velocity. Toto, and many others, do it by dumping water through a large opening, very fast. Then noise is usually near the beginning of the flush. This makes a bit of noise, but not much, and especially quieter than the pressure assisted options which some liken to a jet taking off.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013