The Yamaha seems to have quite a bright tone to me - especially after hearing older horns for years - like your Martin. Key action and intonation should be better for you however. You just need sort of a dark piece to tone down that brassy quality. May I recommend this research: Patrick Springer hand finished hard rubber mouthpieces at www.springermpc.com Fred Rast at www.rastmusic.com Ralph Morgan available at www.junkdude.com - and elsewhere, I'm sure. You can read about what these quality mouthpiece makers have to say on their different models - as well as what users have to say. Good Luck.