hello. I am in ownership of two tenor saxophones. I'm waiting for the second to arrive. Both have a standard b flat mouthpiece but one has a "C4" mouthpiece What is that? Is it the C note in the fourth octave or something? I have quite a few reeds and the strength i usually play is two. I have some two and a half and threes as well. playing the three's gives me bulging veins and the two and half are labouring. I have noticed a deeper tone when i play these but i believed the difficulty was due to lack of experience and strength which would develop in time but I've seen on websites that this issue is more to do with the mouth pieces that my personal experience. Is this true?