Re: can you raise a flat C#?
The selmer series III horns have a vented C# that works great, but I don't know any way to mechanically alter a horn so that the C# isn't flat. There are, however, a few altered fingerings you can try. For middle C#, use the octave key, the third finger of the left hand (the "g" key) and the G# pinky key. You can also try the side c key. Flat C#'s and Sharp D's are just another fun little joy of playing saxophone.