There's just simply nothing better than boron for cantilever material. Japanese got it right. Boron is only 20% denser than beryllium, but boron is 50%+ stiffer.
Beryllium cantilevers only come in a rod form, whereas boron can be made into a pipe. Pipes are potentially lighter and pipes can be made with a wider diameter increasing stiffness even further.
Propagation of sound in both boron and beryllium is similar.
Aluminum and aluminum alloy pipes are standard. They propagate sound faster than any other less exotic metals such as steel, copper, titanium, etc. Aluminum has low density and can be made into a wide diameter pipe resulting in very high stiffness. Ortofon 2M Black does just that.
I would imagine aluminum alloyed rods to sound terrible... But I don't think I've ever heard a cartridge with one.
Carbon fiber cantilevers sound very bad to my ears. So do ruby and sapphire.
Beryllium cantilevers only come in a rod form, whereas boron can be made into a pipe. Pipes are potentially lighter and pipes can be made with a wider diameter increasing stiffness even further.
Propagation of sound in both boron and beryllium is similar.
Aluminum and aluminum alloy pipes are standard. They propagate sound faster than any other less exotic metals such as steel, copper, titanium, etc. Aluminum has low density and can be made into a wide diameter pipe resulting in very high stiffness. Ortofon 2M Black does just that.
I would imagine aluminum alloyed rods to sound terrible... But I don't think I've ever heard a cartridge with one.
Carbon fiber cantilevers sound very bad to my ears. So do ruby and sapphire.