In answer to your question...................

[Gen. Dreedle]

I had not made any comparizons. Bought ferrits and mounted them. Nothing changed in the 200K Hz range, little rounding of square waves, reduction of HF noise, not a big change in tonal presentation, just the signal is cleaner: i can live with, or without.
I doubt any big changes due to the Q of various ferrites, considering the involved inductances. Am-i wrong ?

Yes, you are wrong. (As usual, but that is not the point of this.)

Ferrites do not work on the principle of inductance. Yes, some inductance, at some low frequency. It is inconsequential. That is not how they work.

It is the frequency-dependent resistive element that is responsible for the losses. (C'mon............how hard is this to figure out...............only resistive losses can convert energy to heat.) I am not going to 'splain any of this again, but if you are really interested, there is a good chance this was 'splained over at Greaser's Palace.

Not to be confused with Chance the Gardener.

"I like to watch."

Spoken like a true perv...............

[Gen. Dreedle]

Good grief..................are those people stupid, or what?

Can we model them as a series component with some impedance versus frequency curve? How would we calculate or simulate with them, and how would we design such that we arrived at the requirements for the bead? Or are they simpler to think of as just low-pass filters with a relatively-high cutoff frequencies? Or as tiny inductors?

It has already been done, you jackass. Every manufacturer of ferrite beads shows those curves. If they don't, there are other ferrite companies to buy from.

Incredible. See, proves what I have been saying, for years, when it comes to SPDIF:

Audio guys think like audio guys. If it goes in an audio system, then it acts and behaves like it is audio, and we treat it as such.

Tiny inductors....................tiny minds, more like.

(How hard is this stuff, if a dumbass hillbilly like me can understand it?)

[seagreen]

20 Hertz to 20 kiloHertz is all that matters.

Seventh harmonics can't be heard, etc.

Later update: I'm disappointed how the discussion has progressed.