Is there such a thing as audiophile parametric eq?

I believe analog is the way to go for a variety of reasons. One is that the phase shift in the analog eq is the oposite of the phase shift created by a room mode--thus you are automatically correcting amplitude and phase. It's also extremely transparent and leaves the upper frequencies alone. As Shadome pointed out trying to EQ above 200 Hz (I might go as far as 250) is not going to work terribly well. Our EQ functions 350 Hz and below, but we do recommend that you only use it up to 250 Hz.

[http://www.rivesaudio.com/PARC/PARCframe.html]Rives Audio PARC[/url]

We are the manufacturer of this product, but we built this product for this exact purpose and built it to be as transparent as possible. The circuitry used in the parametric is the exact same in API mixing consoles, which are undoubtedly the finest analog mixing consoles made.

Restock: I do not have a reference, though I imagine that somewhere in the Harmon reference white papers it's there--just a matter of getting through them all. It's pretty common knowledge amoung acousticians regarding the phase shift. As to the averaging and positioning, you are correct. We always recommend you work with speaker position and listening position before calibrating the EQ. You will find that once calibrated it's better and just about all locations, even if you calibrated for only one spot. We've done tests with averaging and usually get worse results because it's masks a portion of the problem. This is not intuitive and not what we originally predicted. It was literally hundreds of calibrations and testing that led us to this conclusion.

Restock--yes the physics are surprising, and I'm a physicist, but if you look at the results individually of what's then averaged it makes sense. The averaging becomes a mask of some of the biggest problems. Because the biggest model problems also yeild the biggest nulls at a different location. When you reduce the peak, oddly enough the null is not as larger an aberation relative to the rest of the field. However, if you average those nulls in then you never deal with the biggest problem axial modes fully. It really does go against common sense until you examine it fully.

Shadome: We measure with a continuous sweep, so it's not averaged at a specific octave. However, we do have a psycho-acoustical response filter that integrates much like the human ear. Lower octaves are integrated with larger intervals than higher octaves. I also agree that corrections should be for significant issues--not 1 Hz issues, but the psycho-acoustical response filter takes care of that automatically for us.

I agree with the notion that no eq is the best eq. Even though we sell the PARC I'ld rather have a room that didn't need it, but that's not always possible If you need an eq, it's far better to add that into the circuit than let the room dictate what your sound is going to be like (particularly in the low end). The topology we use is straight out of API mixing boards. These guys make 1/2 million dollar all analog boards--considered the best in the recording industry. Chances are many of your recordings have this circuitry and much more on the recording end of things. So why not use it on playback if you need it? It absolutely beats the alternative.