working on long tones helped me. maybe start a few notes above the ones that you are having trouble with and slur down one note at a time. you may also need to use more air

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. John

Assuming that your horn is in good shape, the only answer is to practice. Adjust embouchure accordingly. You should have no trouble getting low notes.

The reed is very often the culprit. Find a reed that makes the low notes very easy. It might suck for the rest of the horn but that doesn't matter for the sake of practice. Choose a soft reed that allows you to play the low notes with little effort and slowly work your way up the horn. thedifference between the way you play the lowest note on the saxophone and the way you play the highest note on the saxophone should be very similar. Intonation is key however. DO NOT USE A TUNER! Tune with your ears not with your eyes.