Bear in mind, that not all babies like "noise" as they sleep. My daughter was noise sensitive and got over-stimulated easily... and if there was even a toilet flushing in the distance... she would wake up or not be able to sleep.
Try "white noise." You can find those white noise makers, at say Brookstone, Sharper Image, or in www.amazon.com
For my son, we use a fan on low, when he naps. And for him this works.
Or, do a Google search online for that Dr. Phil one you heard about.
*I notice you requested advice before on how to help your baby nap... since she would nap only when driving in a car?
PERHAPS... try some kind of MONOTONOUS repetitive sound, that is calming. It creates a sleepy type of response, in some people. Thus, "white noise" machines... and this MAY replicate what the "driving in a car" did and made your baby sleep.. sans the car movement.
But each baby is different....
All the best,
Susan