Not The Same Sound

Hi David

I practice 1st Position ( C ) Blues Scale. When I get to 3 1/2 step bend and 2 1/2 step n 2 whole step . It Doesn't sound the same ( when u do it ) The same thing when I practice the Major Pentatonic when I get to the 3 whole step. its that nice hollow sound u get. trying to adjust my tongue position n mouth chamber. I notice that if I move a little closer the
( 2 ) n draw it sounds a little more ( Hollow but still not like when u do it )

Thanks Harplayer