Role of the Ligature
As a technician I have a good amount of material on how to repair instruments, both old and new, in addition to other writings about all areas of sound production. In one particular book from Ernest Ferron the clarinet revealed
To quote a section from this book
Ernest Ferron said:
Even with an ordinary mouthpiece, pressure tends to separate the reed from the mouthpiece which explains the role of the ligature in sound production: a ligature made from a flexible material conteracts this phenomenom.
This doesn't exactly answer all of our questions about ligatures. Some people can hear a difference and others cannot with various ligatures. To me, as the player, I can perceive differences in a wde variety of ligatures. But one important aspect is to make sure that you never over tighten a ligature. I always tighten it just enough to keep the reed in place, then a tad more.
On some ligatures, such as a Vandoren Optima there is a plate that has 4 "pins" on it. If you overtighten this plate, the pins simply dig into the reed and you are subjecting the reed to the entire flat plate. Even Rovner ligs can be overtightened. I've heard of people tightening them so much that they bend the screw ?!?!
If you take a look at a lig on the mpc, there are alot of sections where the ligature does not touch the sides of the reed. It basically holds the reed up to the mpc without creating a "squeezing" effect to the reed. On a basic Rover flexible fabric, it holds all aspects of the reed. On very old metal ligs it pinches the reed.
Several years ago I was playing clarinet for a retired pro clarinet player. I was using a standard lower double screw metal lig - yes, one of those cheap ones. Now, newer (and older) double ligs can have a cradle for the reed. I'm talking specifically about one that is simply a round band that has no cradle.
As I was playing (mostly 20s-50s tunes) he commented that my tone had a high pitch ring to it. It took me a few minutes to actually hear this anomaly (ie, ear training). But when I did, it was quite annoying. I probably tried 7 clarinets, half a dozen mouthpieces and reeds and the high squeal was still there. It was very annoying. I then grabbed one of his ligs and that squeal disappeared.
It was quite an eye (or actualy ear) opener for me and the impact a simple ligature can have.
Of course, the ligature holds the reed to the table of the mpc, and the mpc table should be as flat as possible and rails should be as even as possible. Otherwise, a bad mpc can have adverse effects no matter what ligature or clarinet you are playing.