Hi there,
I often use a parakeet using womach's windock production and it works great, even if sometimes my parakeet makes a lot of noise. Other times instead it stays silent, it really depends, I don't know on what. I have always used it as an opener so no problem. Next friday however I want to use another parakeet as well, I've only had it for a week or so but it's very very tame and doesn't mind being handled. I keep them separeted, but when I leave the doors open and they hear each other they chirp like mad. I'll put this parakeet behind a magazine, using a trasparent plastic bag (I made holes, don't worry) to be produced about 5 minutes after the other, that will however stay on a cage on the same table where the other is hidden.
My problem\fear is noise. How can I avoid them chirping too much? should I keep them in the dark before the show so at least they will be sleepy, should I let them stay together so they get to know each other or should I avoid them seeing each other? I also use a cockatiel in these 10 minutes so it'll chirp to them as well I'm afraid.
Any tip is greatly appreciated!

My biggest tip would be to have them DNA sexed.

Male parakeets are much quieter, and they are the ones with the blue cere (section where nostrils are located). They are always much quieter and chew less. In addition, you should try to get them as young as you can, so you can work with them a lot as babies.

Also, I suggest playing music to cover the noise if nothing else works. On stage you don't have to worry about it, but in closer settings it's a concern of course.

Hope this helps!