Boy, Ed! Did you open up a can of worms! Okay, here goes...
The harmonica is considered a "Concert Pitch" instrument. This means that when you play a C4 (aka "Middle C" ) on your harmonica, it sounds the same as a C4 on the piano. The Saxophone, on the other hand, is considered a "Transposing instrument", which is a musical instrument whose music is notated at a pitch different from the pitch that actually sounds (concert pitch). Playing a written C on a transposing instrument produces a pitch other than C, and that pitch identifies the interval of transposition when describing the instrument. For example, a written C on a Bb Tenor Sax sounds a concert Bb.
Also, different saxophones come in different keys. The Soprano and Tenor Sax are in the key of Bb, while the Alto Sax and the Baritone Sax are in the key of Eb. SO, when we speak of the transposition of instruments like Bb Tenor sax or Eb Alto sax, we are referring to the note on the piano (or any concert pitch instrument) that
sounds like āCā on the transposed instrument. A "Bb3" on the piano sounds like a "C" on the tenor sax, whereas an "Eb3" on piano sounds like "C" on the alto sax.
I've actually tried to play along with a Low Eb harp while my husband played his Alto sax. Even though I was playing a concert pitched instrument in the key of (Low) Eb, it still didn't match what he was playing.
If you want to play along with a saxophone, first you need to get the music for the piece. Is the music for a "C Instrument", or a "Bb instrument", or an "Eb instrument"? If it's for a C instrument, and you're wanting to play with an Eb Sax (or vice-versa), you're going to need to transpose the piece yourself.
This chart will help you transcribe from one to the other:
Saxophone Transposition Chart
Clear as mud?
Edited 1 time(s). Last edit at 03/11/2015 08:53PM by EarthDogHarpin.