Re: how to play low notes better.
Hi Azurealto. First of all have your sax checked to make sure there are no leaking pads and that the keys are in good adjustment. It is unwise to loosen or relax your embouchure in an attempt to play the low notes. The saxophone embouchure should be the same for all notes low Bb to high F. The altissimo register is a different story.
I suggest you practice with just the mouthpiece and neck alone. Adjust the tightness of your embouchure so that an Ab Concert (F on the alto) is produced. Play all of the notes on your sax with this same embouchure feel.
The low notes require lots of air! Play the following exercise as loud as you can at first. I would suggest you start on low G and slur down quickly to low C and hold the low C as long as you can. Keeping the embouchure firm, the throat open (as in singing AH), and lots of air will produce results with some practice. Once you can slur down to low C and hold it with control, then practice starting on low C. Good luck.