For legit, Rovner darks do the job just fine, and that's what I use. No, I wouldn't say they deaden the sound, just tone it down a touch and warm it up just enough to maintain a decented, dark sound. And you're also right, they just don't seem to work as well for jazz. If you want a real good lig, go for an Olegature. I like them a lot. No, ligatures don't help as much as most people believe them to, but change your sound. What I like about the Olegature is you can change the screw tightness to modify the sound (and a pamplet telling you how that works, comes with it.) You can buy the Olegature right from this site and it will probably save you $30.