Writing about ligatures is an awful task because everything ligature-related is so subjective.
All I can tell you about ligatures is murky.
There has neither been empirical nor scientific principals that have been established that prescribes what the design of a good ligature should be.
One school maintains that the fewer points a ligature contacts the reed, the better.
One school maintains that a “strap” around the reed and mouthpiece is best.
One school maintains that the reed produces the best sound when it’s held down by metal rails. One school maintains that the reed produces the best sound when held down by cork, plastic, rubber, or other material.
One school maintains that how the ligature comes in contact with the reed affects sound.
One school maintains that the type of plating on metal ligatures affects the sound.
One school maintains that the material the ligature is made from is a big deal.
It goes on and on, but aside from leading to delirium, there ain’t no proof of anything ligature related. Almost everything ligature-related is subjective, and dependent on the mouthpiece, reed,... well, the whole rest of the clarinet including your playing habits.
All I can tell you is what I think, and pretty much what I think is that whatever you think is fine to think because I don’t think that what I think about ligatures is what you may think about ligatures after you play various ligatures.
The original ligature consisted of string wrapped and tied around the mouthpiece and reed. Many many players, especially in Europe, still maintain that this is, and always been, so. In fact, many German mouthpieces are grooved to accept string because string slips off of other mouthpieces so easily (and they're hard to tie).
To get around this, Vandoren has created a woven string ligature that supposedly will stay on a normal mouthpiece.
The basic metal ligature was supposedly invented by Iwan Mller in the late 18th or early 19th century, and I suppose that all other ligs developed from that until just lately, when hybrid ligatures like the Silverstein, which combines string with other materials.
All-metal ligures became pretty much standard in the U.S. by 1900, entirely wrapping the reed and mouthpiece, but at some point (no, I haven't researched it and don't intend to) the Bonade metal ligature, which has two metal rails holding down the reed, became ubiquitous.
The two-rail design, with many variations, has persisted, some replacing the full rails with individual "pressure points" to hold down the reed. Some of these ligs have replaceable "rails" of different styles that supposedly change the sound.
There have been offshoots of the rail ligatures, some fairly bizarre.
A third main type of ligature is what I call the "slip on" design such as the Bois ligature, made of plastic, rubber, wood, or whatever, that has no tightening mechanism other than friction.
Anyway, without going further, there are surely hundreds of different ligature designs. Just do a search for "clarinet ligatures" and be overwhelmed (being appropriately impressed with all the hyperbole about how each one is superior to every other or that will transform your sound, and so on and so on). Some of the designs are pretty bizarre.
My general thoughts about ligatures:
⦁ A particular ligature usually, but not always, will have an affect on the sound and response, but it will not transform your sound from mediocre to great.
⦁ Many of people claim that the plating material of a ligature, especially on Bonades, makes a difference. I haven't tried them, but I'm skeptical. (See below.)
⦁ I don't necessarily hold to the principle that a ligature that holds the reed as lightly as possible or that has the fewest contact points is superior.
⦁ The concept of pure-string ligatures may be valid, but they'll be fussy to tie and hard to keep in position unless you own a mouthpiece especially made for them. I've chosen not to explore them.
⦁ The price of a ligature does not indicate how good it will be for you.
Here are a few ligatures that I've had experience with and recommend:
⦁ Luyben. Plastic, cheap, and very good for players through the beginning advanced level.
⦁ Bonade. A standard that many high-level players swear by. I played a vintage Bonade through my short professional career. When I started playing again, I preferred the Gigliotti, then changed a few times since then.
⦁ Rovner. Eddie Daniels Carbon Fiber, Versa, or the discontinued Eddie Daniels model. I play the Eddie Daniels Carbon Fiber and the old Eddie Daniels models, and can tell no difference between them.
⦁ Silverstein. I tried one, and I liked it a lot, but wouldn't pay the asking price. If you're and advanced player willing to pay the money for a relatively small improvement, go for it!
⦁ Vandoren leather. I like this ligature for chamber music. It produces as "softer" sound than the metal ligatures I've used.
⦁ Vandoren Optimum. You see many of these around, and this ligature helps for those players who want an "American" sound with a defined "core" to the sound. My own sound concept is not the "in your face" American sound, so I don't use it on my soprano horns, but do use it on my bass clarinet.
I have a Bois ligature (the single narrow ring one in the photo above) in my case for emergencies, but I wouldn't choose it as a primary ligature. (Here is an example of why I don't buy the idea that the less a ligature contacts the reed, the better. Though with less contact contact than any other ligature I've played, the sound is dull.)
I've also played a few of the Rovner ligatures that are just straps, but don't have any kind of rails or anything else that holds the strap away from the reed. They're okay.
Aside: Many metal and metal-hybrid ligature manufacturers offer their models with various plating--silver, gold, platinum, and.... I'm skeptical about the differences, if any, various platings make, but I'll never find out because I'm not going to spend thousands of dollars. Plating may make a significant difference. I doubt it, but am willing to be surprised as you all send me all the various ligatures models with all the plating options.
I've written enough. If you have any questions or want me to expound on some other ligature-related thing, please let me know.
Over and out.