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CHIEF BONEHEAD Education Class

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20 minutes ago, JohnA said:


Edgar, didn't that Butterworth comment apply to the filters used in the demo, not the ones in the actual speaker?  As I remember, the actual network had 2-pole filters that achieved about 24 dB/oct and included driver EQ.  THAT was the clue to the work Roy put into the C IV design.  I had done something similar mating an FH-1 to an Altec 511B/902-8B.  My treble high-pass achieved 18 dB/octave with a sag in the response to kill a hump in the driver's output, all with 2 elements.  I spent weeks on that design. 


I believe that you are correct -- Roy was referring specifically to the filters used in the DSP. But a two-pole (12 dB/octave) digital filter translates to a two-pole analog filter, and vice-versa, at least for the kinds of digital filters used in most commercial DSP units. 


But I think you're referring to the fact that the combination of a 2nd-order (12 dB/octave) analog crossover filter used in the actual speaker, plus the response of the driver itself, can end up being a 4th-order (24 dB/octave) acoustic response, or 3rd-order (18 dB/octave) acoustic response, or a number of other responses depending upon how creative the designer gets. That is quite true, and Roy did a really nice job of explaining that with the measurements that he showed in the lab. Analog filter elements (capacitors, inductors, resistors) interact in ways that digital filter elements do not, which can be either a curse or a blessing.

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6 hours ago, Armano said:

The second photo is amazing, apparently this is a studio for suppressing sound noise from outside for a cleaner and better sound?


If you are referring to the second photo in the original post, that is called an anechoic chamber. It is designed to absorb all sound that reaches the walls so that there are no reflections, and just the loudspeaker itself can be measured.

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3 hours ago, jorjen said:

I stood in that thing not long after it was completed in the early 80's and it really screwed with my equilibrium. I was not accustomed to it. That caused a chuckle from PWK.

I've been in the one at the Klipsch HQ in Indy. It was kind of eerie. 

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Nice knowing you Jessie Hull, I just banned you as a spammer with the dissertation spam site.


"It's especially pleasant to realize that not only your children are college students, but you too are learning and developing. And learning from the best is doubly pleasant. This is what I have been waiting for a very long time and finally, it happened. I believe that it's never too late to learn and you can start at any time. The main problem I encountered was written work. It was never my strong point, so I had to solve it with the help of [website that sells dissertations]. 


Roy Delgado has a degree in Electrical Engineering from one of the top schools in that field (UT).


PWK received a BS in Electrical Engineering from NMSU (the Engineering School now bears his name) and an Engineers degree (EE?, it's a post-graduate degree, but not a Masters) from Stanford (same class and Hewlett and Packard).


Neither of them needed a dissertation service to get by.


If you have to cheat to pursue your educational pursuits, you either need to switch fields to something else, or pursue a different educational path.





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...and probably none can get by with it today. When I taught Comp I & Comp II, we used Turnitin.com, which catches plagiarism down to the repetition of phrases (if desired) used in published and student-published writing.  

In a parent meeting, after awarding a zero to a student's final research paper in Comp II, I showed them on a SmartBoard where the plagiarism occurred. They were astonished to see the entire essay highlighted. It was bought from a research paper web site. They had stormed in with loud exclamations about suing, but quietly, meekly left.


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On 3/3/2021 at 10:37 PM, dwilawyer said:

Roy Delgado has a degree in Electrical Engineering from one of the top schools in that field (UT).


I didn't realize he was a Volunteer!  I'm impressed, "Go Vols" (says the Ohio State fan)



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