Shoe Trigger

Shoe Trigger

How can I eliminate shadows behind ear or face on portraits?

Approximately 95% of my photos are portraits shot indoors at various locations (for id cards or graduation portraits).
I use a Nikon D40 and place two JTL S-25M slave flash about 6feet from the subject and 3-4 feet across on either side of my camera.
I use two 30" umbrellas and sometimes I just bounce the flash off the white ceiling.
I use the camera's flash to trigger both slave flash (I do not use any flash on the hot shoe).

I always get a shadow on one side of the ear of face, whether I turn the camera on portrait or landscape. Periodically I get shadows on both sides of the ear or face.
How can I eliminate these shadows? I cannot afford an expensive set up.

A picture of what you're talking about would be better.
But I'd suggest some reflector's (they can just be white cardboard) positioned about even with your subject, and at about a 45 degree angle from your camera, or at least a bit of fill flash on your backdrop, not much though.