Since the saxophone’s pitch selection is based off of this principal of length and tone holes, the fingering pattern follows a natural up and down flow. What I mean by this is that as fingers are added (pushed down) sequentially down the length of the instrument the pitch is lowered. As fingers are raised sequentially up the length of the instrument the pitch is raised. Saxophone players eventually get acquainted with this natural up and down flow of their fingers.
However, there are two areas on the saxophone where the natural flow of the fingers is interrupted. One is the finger movement that occurs when changing from between the pitches B and C (does not apply to the lowest register – only middle and upper register). We push down the pointer finger of our left hand to play B. Saxophone players consider this to be their highest finger on the instrument. Then, to ascend to the pitch C, we lift the left hand pointer finger and push down the left hand middle finger (moving backwards or down one finger). This backward motion takes some getting used to, and in some cases it causes decreased speed and dexterity in technical passages.
The same issue occurs when traveling between the pitches F and Gb (or F#) in the low and mid registers of the instrument. The fingering for F requires us to push down the pointer, middle and ring fingers of the left hand along with the pointer finger of the right hand. When traveling to a Gb (or F#), we must lift this right hand pointer finger and push down our right hand middle finger.
The alternate fingerings for these pitches allow us to maintain the natural up and down finger movement of the saxophone. For C, we keep the B key down (left hand pointer finger) and add the middle of the three side keys near the right hand (the specific key is clearly demonstrated in the accompany video). For Gb (or F#), we keep the F key down (right hand pointer finger) and add the alternate Gb (F#) key (the specific key is clearly demonstrated in the accompany video).
This technique can be very useful in passages where our fingers need to creep up and down the saxophone quickly with no jarring movements. The primary example of this is the motion found in a chromatic scale. By way of review, the chromatic scale is a scale composed of all half steps. It includes all 21 musical pitches found in Western Music. In the accompanying video, I demonstrate the application of these alternate fingerings when playing chromatic scales on the saxophone.
Another playing situation in which these alternate fingerings are useful is the trill. A trill is a rapid alternation between two adjacent pitches continued over a measured length of time (a set rhythm such as a half note, whole note, etc. with a trill marking above it). When trilling between B and C, or F and Gb, the reverse finger motion of the primary fingerings limits the achievable speed of the performer. When using the alternate fingerings, the performer can achieve a much greater trill speed.
This Learning Music With Ray video discusses the alternate fingerings for the notes C and F# on the saxophone. In it, I explain the design of the saxophone and the natural tendency for the pitch to be lowered as keys are pushed down, and raised as keys are let up. I then explain how the primary fingerings for C and F# go against the natural up and down flow of key movement, and how the alternate fingerings help to maintain this flow. Finally I demonstrate situations where the alternate fingerings can be applied.