The saxophone neck is crucial to making a quality sound. Probably the most important saxophone part, the neck of the saxophone helps to shape the overall sound of the saxophone.
The sax neck is one part of the saxophone you want to take extra care with. Never go lifting your sax by it's neck, you're just asking for trouble. Any dent's creases, splits or nicks, dirt build up and even condensation will have a large effect on the sound you produce. To put this in perspective, if you blow a column of air down a smooth, straight tube the air will flow freely. Do the same on a tube with a dent in it and there will be compression of the air at the point of the dent. This compressed air will then have a knock on effect on the rest of the air. It's simple physics but we won't go too deep. Just trust me when I say look after your neck.
Yes, people do mess around with the overall shape of the neck by either compressing or expanding it in certain places. But these guys are professionals and they know what they need to do to refine a neck to get a certain sound or make it more free blowing. Please don't go taking a mallet to your sax neck, it'll only end up costing you money.
Saxophone Neck Information
The neck of the saxophone can come in different materials and different coverings suited for different types of sax. The higher end sax market has a ready supply of sax necks for sale made from wood, brass, bronze, silver. Gold plated, silver plated, lacquered, unlacquered etc. What to choose, if you are in the market will only become apparent once you have been playing for a fair while and know how you want to shape your sound. If you are desperate to change your tone, try a new reed or a new mouthpiece rather than rushing to your nearest dealer to buy that 'oh so needed' saxophone neck. Failing that find a professional sax repairer who knows his stuff and ask him to adjust the sax neck for what you think you want. Do please bear in mind that if you do have it adjusted there are no guarantees that the sound you get you will like or even that you be able to get back the sound that you had. That is dependant upon the skill of the technician. So please don't go around battering the life out of your saxophone neck in a vain attempt to alter your tone.