What does a tonearm contribute to the sound of a turntable?

 ++millercarbon
 Wow! He  covered everything!   A REALLY important consideration is Cartridge Compliance and the Tonearm choice that MC mentioned above. A rigid arm requires a compliant cartridge!  Much more than 10. The more the better if using a stiff arm! And Vice-versa with a compliant arm.  An MC cartridge won’t do that without spending a million $. They do cost more for a reason. They sound better, whether  choosing MC or MM/MI.
You can join vinylengine.com and see a graph that compares compliance of the cartridge and the rigidity of the arm, together.  Additionally  there is a really elaborate [sic. accurate] calculation that will help you calculate it more accurately than that graph, somewhere on the Internet.
Again, listen to what Mr Lederman has to say!
Bent

Without one the sound is very attenuated.

Read most of this and have a question.  Back in the "old days" there were controversies regarding detachable heads and fixed heads.  The Shure (SME) 3009 had detachable heads and others had fixed heads.

I remember many articles that preferred the fixed heads for many reasons.  (The detachable ones were much easier when changing cartridges, as I remember!)  Has this changed with today's arms?

Back then, Linn Sondek had the better belt-drive tables and Technics came out with direct drive and everyone was crazy over that technology for a while.

Since I still have both types of tables from back then, I was wondering what today's world finds most accurate in drive types for tables, and which arms are considered to be the most accurate (fixed vs detachable)?

Cheers!

Maybe the proper question is what does a turntable contribute to the sound of a tone arm?

In a perfect world a tone arm contributes nothing to the sound. It just allows the cartridge to track the record and convert mechanical squiggles into electrical impulses. Practically it adds distortions. The better ones add less than the mediocre ones.