Attach there are an review about the possibilities of cryo treatment and why the changes ocurr.

Thank you both for our answers-unfortunately it seems to be still rather unclear what's happening and whether the effect is more a placebo than anything else.

Until this day is not known for sure what are the mechanisms of change that occurs during the cryogenic treatment of materials. For this reason people cant obtain always results in the same sense.

I experiment with cutting tool, and differents batches with the same operating conditions, gives me significantly differents results.

Still need to keep mor experimenting.

Thanks Daniel, It's an interesting topic and probably i will do the test with a vintage saxophone - before and after - let's see - I trust this works (if the instruments has been deformed a lot and tensions have reached a certain level). I imagine these tensions can be reduced to a certain degree (dislocations are the source of all evil - I always knew that .-) ) - I would just feel better to understand what's happening - but I also believe that you cannot compare different instruments (of the same kind) even if the serial numbers just differ by 1. There is just too much manual work involved which adds a whole dimension of differences.  

Tufts did a study with trumpets, but it was inconclusive.  Given the expected natural instrument to instrument variations due to construction, a better approach would have been for them to have the trumpet players play 5 non-treated trumpets during a few different sessions to establish session to session correlation for the ratings for each trumpet.  Then they could have cryo treated the trumpets and repeated the process in order to see the effects of cryo treating on each individual trumpet.

Recording the playing sessions, and then using pro trumpet players to crowd source separate rankings solely based on what they heard would have also interesting.

http://www.tuftl.tufts.edu/musicengineering/research/cryo/cryo_paper_asa.pdf

I had the treatment made on two of my saxophones: I swear it works and it does good - the response is clearly better, but having said that it may be more my feeling (which indirectly leads to a better sound), but maybe it's to such a subtle degree that we cannot scientifically prove the "improvement" or relate it to a microstructural effect.

I could make some experiments in next months with Cu Al Zn alloys.. The original aim is to test feasibility of low pressure die casting and rheocasting. Variants could be testing some (possibly.. new) shape memory compositions.. And cryogenic treatments.. Which could be enough:) but I have visited before a small producer of brass ( instruments) so why not trying some developments??

So I have a request for suggestions instead of a real answer!!