It sound to me like your arrows are making contact. Do you hear smacking? It could be as simple as a nock point problem. Try to experiment between about 3/8's to 3/4" above 90 degrees. Also read through OL Adcocks tuning tips on his website.

As far as your question about canting the bow, yes it is normal. Just make sure all other things also move with the cant such as head angle, draw hand angle, etc.