for whatever reason my 11" is erratic like crazy . The 17 is super stable. I plan on taking the excal there next trip..The excal pinpoints WAY better and I really enjoy the zero guess work of hear it/dig it.. My ear can't really tell the difference between a dime/quarter/or penny. I don't really care to try anyways. If it pp and it disc, and its consistent in tone, I dig.