Humphrey said:
As a prelude to complaining about subjectivity you head your post with a subjective comment (2 in fact). Which aspects do you refer to which can be sensibly compared? Sound? err... Aside from that being a totally subjective judgement, what else is there? Volume? Notes per second? They're measurable so I guess we could be objective there. It's a shame that we can't commision some contemporary Arban to write technical band exercises for competitions. Just to test technique!! Until we reach that Utopia we have to use real music which unfortunately touches us on a more personal level. Our responses are inevitably bound to be subjective. Judging a contest on volume and a soprano cornet split count; that's the usual brass band bull****! I think I prefer the approach of Messrs. Sparke, Ball and Read.
As an afterthought, a splendidly shaped and intelligent performance may need to more closely follow the score which after all is one of the only objective judgements we can make.
Yeah, okay, I was trying to have my cake and eat it in my previous post. The comment about YBS's low placing had a measure of disbelief in it that the trained men in the box (who you assert ignored TUBBBS to judge on more subjective grounds) didn't share my subjective musical judgement on their performance to any close degree. I may not have played for Dyke, but my subjective estimation isn't usually so far out! Willingness to downgrade the importance of the occasional splat in the name of superb music-making - it's just as well I'm not an adjudicator, eh...
Less subjective aspects of performance - now you're being a little facetious

. All aspects are of course on a sliding scale - (when does an uncentred note become a split, say?), but there are some which are more amenable to rating than others. Assuming no-one is going to play any wrong notes (and where would Paul Thomas' pedalling for Desford sit there?) I'd start with tuning/intonation and balance. Just there one could have picked out a lot to criticise on Saturday. One could also consider things such as evenness of tone across instrumental registers - was that Euph high Eb a bit strained? Tone quality? Well, as you say, a bit trickier, but would anyone suggest that, say, an airy sound is a good one? If you take care, there are ways to approach pretty much anything which maximise objectivity and minimise subjectivity.
Reviewing my previous posts, I don't think I judged or said that I judged anything on "volume and a Soprano Cornet split count". Did I?
The more I debate and listen to people debate the point of contests, the less I find meaningful about them; really, I'm finding more and more that the results are of less and less importance to me personally. Arguing over them is part of the game but attempting to rank the different performances in order is almost a Zen activity... Like saying "An apple is greater than an orange". The only sensible way to proceed (artistically, anyway) is to divide the perceptions of them both into a number of categories deemed worth judging on that are also easily comparable (size, shininess, regularity of texture, whatever), and remove as much arbitrariness from your judgement as possible. Or maybe one should embrace the Zennosity of one's activity, and say "I decree: the apple is indeed greater than the orange. No further argument is necessary". Opinion seems fairly split here.