who wants tone controls on your next preamp?

I do . . . actually a modern, high-quality tone control arrangement is something I've been working on for some time.

Herman is quite correct in the fact that high-quality equalisation is a necessity in many parts of the recording chain, and anybody that has experience with top-shelf professional equalisers can attest to the fact that equipment indeed can be designed that sacrifices nothing in transparency, detail, noise, distortion, musicality, etc. etc. in order to perform its task. But these units are also available in seemingly endless configurations, each suited to specific applications and engineers' preferences, and virtually all of them must be used skillfully and judiciously to get positive results.

The challange in a high-end audio context is to get just the right amount of adjustability in just the right ways . . . so that the desired, significant improvement can be made the vast majority of the time in just a few seconds. I've used several graphic and parametric mastering EQs in my various systems over the years, as well as a smattering of recording-console channel strip EQs, all semi-parametric in some fashion or another. From this I come to the conclusion that the "knob-count" should be 3-5, settings should be easily repeatable (especially for frequency/turnover), and work identically on both stereo channels. More than five controls starts getting really fiddly, and fewer than three . . . you might just as well have the Baxandall circuits.

I also feel that some frequency-variability is necessary . . . simple five-to-seven-band graphics (i.e. McIntosh) never seem to have the bands quite where they're needed, and using two adjacent bands together usually starts messing things up. Narrower graphics with variable-slope or "constant-Q" filters also IMO start sounding heavy-handed.

Meyer Sound used to make a simple 1U EQ called the VX-1 that was my favorite of the bunch, although it has dual-mono controls and everything's continuous (no repeatabilty). Five knobs . . . low/mid/high with variable turnovers, all constant-slope single-order (6dB/octave). It had sensible range (+6 to -12 IIRC) that precludes the need for making master gain adjustments.

If you go to a quality steak house type restaurant you'll always find salt and pepper on the table. The chefs cook the food to your specification, but as the eater you have the option to slightly season your meal.

Onhwy61's analogy is excellent, and actually one that I use to encourage casual listeners to stop abusing the tone controls - i.e. a fine steak doesn't deserve to get smothered in sauce the way you might a ground sirloin from a truck-stop. I think that a prerequesite for the proper application of tone controls is that the system first sound pleasing to the listener without them, on the majority of recordings for which its used . . .

This is similar to good studio practice, which holds that the first priority (after making sure the instruments themselves sound like they're supposed to) is to use the best microphone for the application, and the second is to place it properly, before any processing or EQ is applied.

But there are a few problems with this idea that by adding any EQ or processing on playback, you're somehow getting away from the artists' "true intention" of the recording. For instance, there is a huge percentage of recording and mastering facilities out there that have rather idiosyncratic acoustics and monitor setups. Mixing and mastering sessions are also very frequently conducted at SPL levels that are way too high, and not at all representative of the playback volume . . . consequently, so many of the people making decisions about the final mix have significant hearing damage -- which I think explains the excessive upper-midrange energy that's present on so many rock and pop recordings.

So insisting that a flat EQ be used on playback, for "pureist" reasons, is IMO akin to insisting that Beethoven's metronome markings always be adhered to literally . . . it simply doesn't work in practice. And if one's musical taste extends significantly into the realm of sub-optimally produced recordings, a little seasoning can make a huge difference, just like an excellent reduction sauce on a sub-par piece of meat. Which just happens to be one of the foundations of fine French cooking . . .