first of all thanks for your work, it's helping me a lot to improve my ear

There are some minor problems I noticed that I want to share with you, so you can take into consideration to even improve your product:
I noticed the vocal range setting also affects the listening exercises. My vocal range is not so great, roughly F2-F4. That makes exercises like interval recognition too easy, because it will not play higher notes. I get an adequate diffliculty, if I set vocal range to guitar or piano, but on the other hand, it makes singing exercises impossible.
I started working on interval singing exercise a lot lately, and obviously, if earmaster plays a C5, it's impossible for me to sing a perfect 5th above.
It's annoying having to constantly change vocal range setting if I want to singing and listening exercises. Is there a fix for this?
Best regards, Franz