Randall is the man and his website is a wealth of solid information.Exactly. Randall Aiken did a great job showing us what goes into a speaker emulator and even detailing the specific requirements of each of the components. As I said, he did a great job, but I don't think we can name the circuit after him.
At the end of the day, you need a series LR element to get the rising impedance with frequency, and a parallel LCR element to mimic the speaker resonance. I don't know of any other way to do it, so any load box with similar frequency response is going to have those electrical components.
But thanks again to Randall Aiken for showing us how to DIY one ourselves.
But I went and had a look at his site and just for the record even though Inductors, Resistors and Capacitors are going to be in most devices like this we are not doing exactly what Randall shows in his white papers and our values are completely different.
This is a problem I have been thinking about since the mid 80s, when I had my big Bradshaw rack and I used to slave amps. I quickly learned that resistive loads didn’t cut it. I just don’t have the rack anymore and didn’t find a need until IRs became popular. I mean the Juice Extractor was a load with an EQ to re-amp and slave amplifiers and the problem with that sounding flat which it did, was because it was resistive.
What I find surprising is most of the Reactive Loads I have measured do not follow a true impedance curve at all.