Alternate cupping and not cupping. One scale cupped, then immediately remove the cupping and do the next one like that. Then next one cup again. etc.

Over time the difference between the two will become the same.

Good singing to you,

Phil Moufarrege
Grow-The-Voice.com

Hey Victor! I'm no professional, however, I have been teaching myself to sing for a couple years, before taking on and off voice lessons with various coaches. What I've learned from private practice and training with coaches is that the goal is to attain consistency in the voice. In my opinion, this means technique stays the same, no matter what. For example, whether a singer is dancing, sitting at the piano, singing with or without a microphone, or in your case, cupping their ear, vocal technique has to be practiced and applied to the point where it becomes second nature.

Also, there's a possibility that cupping your ear isn't really affecting your voice as much as you think it does. It may be more of a mental shift than a physical shift :) When singers cup their ears, it enhances their ability to hear themselves, not release tension in the throat. My suggestion to you would be practicing vocal scales and exercises easy and light (not airy) while recording yourself, then listen back to it. If something sounds off or feels painful, then experiment, research and play around with ways to do it differently until it feels just right.

And don't think of having to re-learn how to sing! I've had this worry for a while now, and I can honestly say, it's more limiting than it is empowering. Singers are always reviewing the basics, no matter what skill level. Think of practice as unlocking your fullest artistic potential, and singing as finding your voice that allows you to express yourself and share your message in the unique and special way that only you can :)

I hope this helps. Have fun and good luck!