Now that you got me started... It's not just knowing the math, but also the
basic concepts as one needs to really understand the basics in order to apply the right formula and use them correctly to get the right answers.
In college/university days we had the saying that any/all math text books that have the word "advanced" followed by mathematics, calculus etc. in the title, don't worry about it as it would be relatively easy to read. If you see something like "Basic", "Principle..", "Fundamental" etc., followed by whatever in the titles, then watch out..
Just a few examples of what many got the concepts wrong, resulted in misnomers and hearsay such as:
- RMS power (actually meaningless for audio amplifiers and loudspeakers)
- Music signal is complex, so you can't test amps with sine wave signals (not totally untrue but the hearsayers often got their reasons wrong).
- Damping factor has to be in the hundreds, if not higher (Crown Audio used to make such a claim but those articles seemingly have been removed since years ago)
- Amps with extremely low THD could sound worse than those with much higher THD that don't, or use little negative feedback.
- AVRs, or amps not rated for 4 ohms can't drive 4 ohm speaker or they would sound terrible.
- Class AB amps would operate in class A at low output and changed to class B at higher output. (may be a few were design to operate that way but I can't think of one).
That's just a few, the list can go on for days, feel free to add.. People who Google for knowledge will continue to come across such inaccurate information and such misnomers and worse, even the wrong/misunderstood concepts would unfortunately be regurgitated, forwarded with good intention thereby perpetuating on the internet, and we get more and more hearsay..
Enough venting, time for my second cup and move on to something more positive.