Is analog EQ technically feasible?
That depends on your point of view. Analog was the only way to do EQ until the digital age. To implement an analog EQ you need filters, resistor-capacitor or inductor-capacitor or whatever, some potentiometers to control the cut/boost per frequency channel, and some gain to make up for the filter losses. The down side is there is always phase shift in and about the bandpass of each filter, and all the extra electronics add noise and distortion, mostly in an inverse proportion to the amount of money you spend on the design and components.
Digital equalizers work in somewhat the same way, only the filters are implemented in computer code and executed on a digital signal processor. Digital filters that mimic hardware filters are relatively easy to implement in software, but that type of filter has the same phase shifting as the hardware version. Better software filters that maintain a constant phase through the bandp of the filter are much more complex to code, and require a LOT more compute power.
With all that said, most recording studios still use analog EQ while tracking through analog equipment. All of the negative things that hardware filters do on the sound reproduction side are part of the recording art, and the changes made by analog filters, phase shifts, noise, distortion, and all, are for the most part what makes recorded music sound the way it does.
So, yes, analog EQ is feasible, but it seems that the audiophile community avoids such things like the plague... This is a Schiit thread; Have you seen bass and treble controls on anything they have produced to date? I've been thinking for a while that Schiit may be working on a phase coherent digital equalizer component....
