Originally Posted by MKtheater
Hey, what is that graph showing?
It shows a bi-quad curve for a specific sub with +10dB of boost and alteration of the naked knee in a loopback measurement. One is using the Berry DCX, one is my SEQSS, one is the Marchand Bassis and one is the MiniDSP 2x8.
It's answering bass addict's Q. Yes, you can successfully use a shelf and several additional PEQ filters to get very close to a bi-quad, but I wanted to show that all of those solutions has a different roll off result. Many digital PEQ solutions have a roll off that eats into the shelf, so I didn't include those because the answer in those cases would be 'no'.
My answer showing roll off variance was directed to bass addict and had nothing to do with my answer to your claim that all DACs are the same. There are variations in DAC architecture and the results have not been tested in the case of a subwoofer. The introduction of noise would be my 1st area of investigation. There is already nearly zero available information for below 20 Hz reproduction and absolute zero is the case for Delta Sigma converters, much less the rest of the components in a $300 do-it-all outboard digital EQ.
There are a huge majority who say that limiters are 100% transparent, the fact that they constantly and infinitely change FR is irrelevant and DSP is also transparent, especially so in the subwoofer passband. They also apparently agree that the values chosen for DC blocking caps is arbitrary and that that approach is 100% acceptable.
I believe I've done more research on the subject than anyone. My conclusion is that known and unchanging preset curves is better than limiter-induced infinitely and constantly changing curves and analog is the more transparent way to achieve the goal vs digital. I'm not going to say more than that (as I did in years past regarding everything else I was constantly put on trial for and had to slog through, over and over) because I don't have the time or the inclination. Folks believe what they want and like to hear what they want to hear anyway.