Personally, I wouldn’t want to get rid of the classical sound that comes with proper training, even if that quality makes it through a totally informal style of fiddling. I believe fiddle players want that sound too, but they’re typically not trained and therefore don’t have a clue how to make it happen.
Keep in mind, fiddlers often use cheap, steel strings. They also often shave down their bridges for some ill guided notion that it makes playing two strings easier. They also rarely wipe the rosin off the violin. All these practices effect the tone, along with widely varied bow grips and violin positions. So these are some things you can think about if you want to achieve that earthy, raw fiddle quality.
My advice is to listen to lots of players playing the tunes you like and, knowing how to practice classically, determine what those fiddlers are doing that you are not. Watch videos on youtube. What do you feel your playing lacks in comparison? In my own experience, I can happily leave behind the terrible hand positions, the scratchy tone and limited ability (no shifting, pitchy intonation) that often accompanies fiddling. I focus more on trying to emulate the bowing patterns, rhythms, and double strings found in fiddle music and to me, applying classical training to those fiddling challenges makes me a stand out that no mountain born, self taught fiddle player has ever frowned upon.
Don’t forget Michael’s book on Fiddling called Fiddle for Dummies which is currently on sale at Superior Violins. Click Here to visit the Fiddle for Dummies Product Page and get a preview of what each chapter contains. There’s also a video on that page to watch about the book, which comes with his autograph! 🙂