Re: Bright Alto Sax sound
It interesting that you say this is something that has recently developed. I'm wondering if perhaps its not just that your ears are getting more attuned to the sound you are looking for (in other words your becoming a better musician).
Given your set up, I would definitely recommend a new mouthpiece. I wouldn't go as far as saying a new horn without knowing more about your background, experience level, practice habbits, etc.... But for sure, a new mouthpiece would help your situation.
Most classical alto sax player today are using either a Selmer (S90, S80 or Larry Teal) or Vandoren Optimum (AL3 or AL4). However, there are other classical mouthpieces out there to try as well. BG has recently come out with a nice classical saxophone mouthpiece. Lomax mouthpieces also makes a good classical mouthpiece (http://www.lomaxclassic.com). You should definitely look towards a better classical mouthpiece asap.
As for the horn, I would wait to get a new one until you have settled into a good mouthpiece. This will be a huge help to you once you start play testing saxophones to know that your mouthpiece is not a limiting factor.
As for embrochure, take some lessons from someone who can make sure you've got everything set right. Bad habbits only get harder and harder to break the more you engrain them into your playing. Embrochure is critical and good equipment does nothing to improve poor technique.
Best of Luck!!!