voice acting advice wanted

I am voicing two characters who are twins. Both voices are made by me just talking normally and then repitching them to sound like kids. The younger twin is supposed to have a slightly higher voice, and I found that the end result is much more effective when I play both characters exactly the same way and make the younger twin sound higher by using slightly different filter settings for each voice when repitching. But I can't seem to get into character for the younger twin unless I am actually talking in a slightly higher and more nasilly voice, but when I do that the end result is less effective so I would like some advice

I would maybe go to a forum such as Voice Acting Alliance or subreddit /r/Voice Acting with this question? You're probably not very likely to find a lot of experienced voice actors or just people interested in voice acting here.

edited 3rd Jun '16 4:57:10 AM by cake1