Compressor question - need help understanding course textbook materials

I’m prepping to teach a class in audio and reviewing the course curriculum. There are three chapters on compressors, and they expect the student to be able to identify the sonic and electronic characteristics of them (which is pretty insane). I think this class goes too deep into the specifics of the circuitry without giving a general framework about the differences.

I’m in the section about different types of compression:

From the book: Diode bridge compressors are fully configurable regarding attack, release and compression curves and are independent of the compression element. This type of design is tonally distinctive because of non linearities associated with the diodes.

So is this thing like an optical with a different type of diode, plus non-fixed curves? Am I getting this correctly?

You’re teaching an audio class, but you also have to teach the electronics behind the workings of a compressor? That’s pretty hard core for audio engineers.

Agreed. This seems like a strange requirement. It’s either written by someone who spent 30 years designing compressors and wants people to know how important his job is, or it’s written by someone who just looked up a list of different compressor types on buzzfeed and thinks he knows what he’s talking about.

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Not the electronics specifically. I looked ahead at the test materials. The students have to be able to know what makes them different from a FET, optical, Vari-Mu, and VCA on a conceptual level, be able to tell them apart sonically (which again I think is pretty crazy) and identify the general application.

So you’d get a multiple choice question like:
Which of the following compressor circuits was designed with the intent of minimizing total harmonic distortion at the output stage of the circuit:
a) FET
b) VCA
c) Limiter
d) Transistor
e) Tube
f) All of the Above

Which type of compressor does not feature the use of a diode as a primary characteristic of its circuit?
a) Diode Bridge
b) Optical
c) Digital
e) LA 2A
f) LA 3A

It looks like the section in the textbook was implemented to keep the course comprehensive.

I can see the value of knowing when to use a particular compressor, such as in a channel strip or in the mastering stage, and how compressors can be used to colour the sound of a track. But tell them apart sonically, like in a blind test? I can’t imagine why that would be a useful skill to know.

I think the line between audio engineer and electronic engineer should be not be all that fine…

That’s like demanding that housewives explain the Otto cycle before they are allowed into their Volvo station wagons…
Who are the students at this course, Jonathan?


I’m supposed to start tomorrow so I’m scrambling to get my ducks in a row (like turning in my W9 to the school and getting my online portal account set up), but I’ll go through the test with the answer keys myself in the next day or so.

I realized a few hours ago that the testing is done online and graded electronically so I can’t go in there and axe parts of the exam (which is certainly crossed my mind). I can’t alter the tests.

Freshman/sophomore college level. Some students are graduates seeking continuing ed for their work. This is a base level electronic music production training program with a DAW emphasis on Ableton. Audio Basic 1 and Basic 2 are Pro Tools centered. And anything related to electronic music is Ableton focused. I’m glad they go through theory about how mics and preamps work, all these guys need to know what stuff. I would like them to understand the basic compressor families, but asking questions about the electronics inside them seems a little overkill.

Aaaaaaah! Ok. Just got back from a show and sat down with the e-book for a few min. I see what’s going on. They’re referencing youtube videos and saying listen at 3 min 20 sec. The effect (the most obvious one) placed on the snare drum is

a) compression
b) flanger
c) gate
d) reverb
e) both a + d
f) none of the above

So they went into the history of circuits, some of the design differences… they also waste time talking about the history of Logic, how it evolved from E-magic and the difference between 32 and 64 bit recording. LOTS of irrelevant stuff. Regarding @bozmillar’s comment earlier, I imagine we all forget how much college textbooks are filled with fluff. Wow.

So long story short, the questions are all based about compressor circuitry. I’m really glad they don’t have to pick them out of a blind test - which is where I thought they were going with that. That would have been insane.

Hahaaaa~ And there was a question in there about the frequencies you would most likely associate with ‘warmth’ in a male vocal. Doh!!!

Welp. Found out I’m not starting until January. Sooooooo never mind lol.

You may want to modify the course material and not focus on circuitry. 99.9% of studio engineers wouldn’t know or care about circuit specifics, nor should they.

I can’t modify the material or the text because the content of ebooks and the tests are scripted into the portal the students use to access the class. The rest of the class is on-site on campus though.

If those electronics questions get crazy, I was thinking about just giving them the answers straight off the answer key before they open the test. There aren’t very many of them.

I’m going to be doing the class for sure, the school was just up in the air about the start date. I had gotten emails that said they wanted me starting today, then I got a follow up this morning that said they were holding off on bringing me onboard until January. All good. No hurry lol.

I think its important, even for undergrads to understand compression. And along with that, to understand compression families. Bridge diode is a family, but its a very minor one. Now the CIRCUIT per se is a whole different field… I don’t see any reason someone has to understand the inner workings to at least know how a FET family comp differs from a Vari-Mu comp in a BROAD GENERAL sense. We’re talking like… jet propulsion engine vs propeller engine here… not much more than that.

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