Dixon trad - has anyone tried filling the cavity?

[MTGuru]

I have to say I'm disappointed by these reports that the Dixon Trad has changed, or may suffer from quality control variations in more recent production. I bought mine shortly after it first became available, and it's a lovely whistle exactly as-is. Sweet, responsive, Gen-like tone with slightly less chirp, even good looking. It's ended up as my go-to deskside whistle, and I've recommended it as a good choice for beginners. But I have to rethink that in light of the anecdotal problems. Unfortunately, until my MacArthur fellowship comes through, I'm in no position to just buy a bunch and check for myself ...

[AvienMael]

The very first one I had (when they first came out) got stepped on and kinked beyond salvaging when it was less than a year old. I kept the head and immediately bought another that I later sold. It was basically the same as the first. Last year I bought a newer nickel Trad. It was not what I was expecting - until I tried the old salvaged head on it - and then it was what I remembered. Not long after that, I bought a brass Trad, also newer, and also with a head that loosened up rather quickly. It too, did not play the same as the older head, and I gave it away.

...and so in that very limited sampling, my experience seems to agree with what most others are saying. BUT, I have tried the tweak on both the "older" and "newer" heads, and I have not found it to be any kind of improvement on any of them - actually, I think it makes a good thing not as good as it was. Nor can I tell you what differences other than fitment, might exist between them.

[Thomaston]

One thing I' d like to say is that my newer Trad is still a decent whistle. Undoubtedly some people would prefer it, as it has a more complex character than the older one, while losing a lot of the pureness.
My primary whistle these days is a Busman, and I'm not using either one too much. MTGuru, I have a proposition. I can loan you both heads with one barrel to try out yourself, if you'll agree to post sound clips.

[Pipe Bender]

my newer Trad is still a decent whistle

I agree. I am still very pleased with the performance of this "newer" Brass Trad. And in my case quieter is better.