How old are crickets before they start chirping? Some of mine have hidden in the tank decorations and have escaped being eaten and have become quite noisy.
If you're willing to spend a little time, you can have silent crix. Since the males are the ones chirping, feed them off first before they do their final molt. The males don't have ovipositors - the little black "stick" on the back end. I've sorted through 1000 in about an hour. Once it's done, it's done. (Unless you have mutant, gender-changing crix. :wink: )