The baffle makes a good deal of difference in the way a mouthpiece plays, feels and sounds. The two baffle extremes range from no baffle to a lot of baffle. I started out putting epoxy in the chamber under the tip to brighten up the sound, a lot of players have experimented with this. It squeezes off the air column forcing it to travel faster through the mouthpiece, thus brightening up the sound and increasing volume. I've played DDs for years in loud bands and rock, where it is a natural sound for that music. Later in years I realized that it wasn't necessary for me and discovered I could get just as much sound out with my L or J even, just not the edge which doesn't concern me so much these days.
When blowing the no baffle mouthpiece, like my Fmaj7 or J for tenor, it becomes apparent there is a freedom that is not had with baffled mouthpieces. The baffle is an impedance and I find especially so in the soprano. I could never make a satisfactory soprano piece till I removed the baffle. It still has a bright and strong sound, though. It's not old fashioned sounding. So the freedom of not blowing against a baffle is a different experience, your whole sound opens up. I think it works especially well with soprano and makes it feel more saxophone-like to play.
Tonal Properties of mouthpiece materials
People often ask me about the different materials and how they affect the sound. The material from which mouthpieces are made affects the sound, color, volume and brightness. The harder materials are louder and they project much more, metal especially. Rubber has warmth, acetal has strength and brilliance. Wood has it's own unique sound, it is louder than rubber. Many mouthpieces (not mine) are made of a combination of rubber and plastic. They sound thinner and brighter and when you get to pure plastic it will sound very thin and hard to play in tune, too. For some this works just fine, but the rubber I use, is free of plastics. Hard rubber is also called Ebonite and is an organic polymer consisting of hydrocarbon chains, bonded together through sulphur atoms.
Acetal is a type of nylon that has a translucent milky color and is an extremely tough material. It is louder and stronger than rubber, just not as warm. Even though it is plastic, it plays and sounds a lot like rubber. I think this is the case because acetal is not brittle at all, it is pliable and resonates freely, that is why it sounds a lot like rubber. It will never chip or crack and is so tough you could drive a truck over it.
Facings are the most difficult part of mouthpiece manufacture. I know this because that is when I do most of my cussing. It has take me many years to understand and conquer the art of facing and I'm sure I still have plenty to learn or unlearn for that matter.
The first thing a mouthpiece needs is a flat table, without that no facing can have any reasonabe degree of efficiency. I put a slight depression under the window to accomodate the swelling of the reed. After I'm satisfied with the table I put on the facing. There are two basic kinds of facings ... one with a short lay (it will have a shorter radius as viewed from the side) This produces a brighter sound and edgier, strident to many. It also responds quicker when playing large intervals. afff Few players like this approach, but prefer the longer, darker and flatter facing which gives a wetter, buzzier and easier blowing mouthpiece with a bigger sound. I make most of my pieces in this manner.
A good facing, with 100% efficiency or close to it, will be loud and full of sound with ability to project well with any kind of baffle setup. Facings can have a variety of problem like uneven rails, flat spots and assorted irregularities causing problems for the unaware player, but I'm sure for some it may produces a unique sound. One sure sign of a poor facing is if you can't find a good reed. Also mouthpieces can warp under conditions like too much heat and I think extreme cold is also not good, but I'm not too confidant about that. A free blowing resonant sound needs to be unimpeded by these difficulties.