BY CHRIS APPS.
If the high A is little thin, there are some adjustments to be made to improve the sound. First, blow through the reed, without the pipe, for 30 seconds. Moisture will change the sound, hopefully for the better. Play it in the pipe to see if that has brought it to life.
If this hasn’t produced the sound you desire here’s some other things that can be done.
Check the mouth of the reed. If the mouth is too closed, try opening it up a bit with a mandrel or reed poker. Re-test for strength, volume, and pitch. Repeat if necessary. This will make the reed a wee bit harder, so you’ll want to carefully sand or scrape each blade.  Once both sides have been sanded/scraped, test the reed in the pipes. If the reed is still a little thin on top and doesn’t yet vibrate efficiently, repeat until the reed becomes more vibrant.
Take it slow. You’ll be surprised at the difference a few small changes will make.
Note that some reeds just won’t respond to this. It’s just the nature of that reed/cane.