So many factors come between you and a good bassoon tone:
YOU . . .
. . . BEAUTIFUL TONE
So, to improve the tone, one must seek to improve every link in the tone production chain.
The serious bassoonist makes many reeds. The idea here is to improve the chances of finding a good one. Since commercial reeds are so expensive, and, usually, not particularly well-suited to the individual needs of every player, the best way to improve reeds is to learn to make them. Work with your private teacher, go to clinics and seminars, attend summer camp, and read a book (e.g. The Art of Bassoon Playing by William Spencer). One way or another, you can learn to make and adjust the reeds you play.
Most generic bocals used with school bassoons are just plain awful. Bocals, too, are quite expensive. But, a professional bocal will help you sound better and, incidentally, will improve your intonation. There are some new bocals on the market now which have been getting good reviews, but prices vary widely. If at all possible, you should try before you buy or, at least, order bocals from a dealer who will offer a trial period (10 days or so). Here are some bocals to try:
Heckel (prices ca. $900) try CC-2
Fox (ca. $750) try *CVC-2* or *CVX-3* (the new R2 models are fantastic!)
Yamaha (standard bocals ca. $200; Super bocals ca. $300)
Many school bassoons are in poor repair; many weren’t good instruments to begin with. A good instrument costs a lot of money. Occasionally a decent used instrument can be had, but buyer beware! Always get a second opinion!
Probably the best deal in a popular mid-priced bassoon these days is either the Fox Renard Model 220 or 240. For a little less, a perfectly serviceable instrument is the Fox Professional Model III (a polypropylene instrument).
Your embouchure may be as unique as you are. Often, though, tone is negatively affected by pinching. Be sure to OPEN UP AND BLOW. Keep your lips tucked in, keep your lower jaw down, and pull the corners of your mouth in toward the reed.
Take a deep breath (as if you are about to swim underwater the length of the pool). Hold it. Keep your shoulders down! Hold your lips as if you were about to blow out a candle. Allow the air to escape, without blowing hard at first, then increase abdominal muscle tension to BLOW the air out under pressure. How long can you last?
Good bassoon tone depends on ample breath support. Don’t let the air out all at once, but you have to work to move the air through the instrument. In the words of one artist player, “THE BASSOON IS A WIND INSTRUMENT!”