I have only been casually following this thread, so excuse me if i make a
broad assumption here. It seems the people who are having trouble with
missed notes on certain songs (Denon's Discord, Charismatic Carillon) have
also stated that the their skills in the required instruments for these
songs (Brass, Wind) are lacking. There is a direct relationship between
your skill in the instrument needed for a song and your ability to start the
song, even if you are singing it not using the instrument.

When you first get Carillon you have awful wind skills, and the first wind
song you can play non-stop to build this skill is the Aquatic Aria (16th
lvl). So till you get to 16th and practice up wind to near max Carillon
will have a lot of missed notes. Same with Denon's, at 18th lvl your Brass
skill is near nil. So trying to start DDD will be a major pain. I noticed
my missed notes on DDD went down a lot when my brass skill got past 80 (took
a lot of practice time). I know keep all my instrument skills maxxed or
near maxxed at every level and my missed notes are not that bad, but still a
pain none the less.

Rokenn Swiftsong - Karana server
Master Brewer of Societus Argenti
Amerginn - Test server