Question about Tone Controls + Equalizers

Jay, being able to adjust a systems frequency response is a wonderful capability but tone controls and analog equalizers are like model T's to digital room control (acts like an equalizer). First of all it helps if you know what your system is doing. Impulse testing with a calibrated microphone does this. Then being able to make specific changes like adding a notch filter and hearing the result are extremely informative. I find that once a system has been corrected the only changes that require adjustment are for specific albums that have problems like sibilance. A 3 db notch filter at 3000 - 4000 Hz usually solves that. So, before this the older audiophiles were right. It was better to correct overall deficiencies is a system as best you could as analog tone controls were more detrimental than helpful given their limited flexibility. This attitude pervades when it comes to digital equalization which is a shame as now the benefits far out weight the detriments. 
Check out Anthem and Trinnov units.

It seems most here use tone controls to correct deficiencies in specific recordings which is great. There is also the realization that a lot of trouble occurs at the 3-4 kHz region and a slider here would be very useful. Cutting here just 3 db can make a huge difference on records with sharp violins, female voices and such. Also because our ear's frequency response changes with volume (Fletcher-Munson) we become way more sensitive to high frequencies. This is what limits the volume on many systems. On some recordings at volume (95-100 db) I have the treble rolled off up to 12 db at 20 kHz. You might notice that some older rock recordings sound a bit dull. If you turn them up loud they sound just fine.
This is because the mastering was done at high volume and everyone was probably stoned. 
Not to worry Jay. This technology will drift down to lower priced equipment. Just keep an eye on companies like Anthem and NAD. 
Just to see what your system is doing on the computer is hugely informative. Comparing one side to the other there are significant differences between channels. These can be corrected improving your system's imaging. All this is done at very high resolution. In my system it is 48/192. The bit depth is need to cover a wide range of volumes particularly in the bass where you can have 10 db oscillations. Bass you can not deal with entirely with digital correction you also have to improve room acoustics as much as you can. 
It is also interesting that a perfectly flat curve does not sound right. My baseline curve is boosted 3 db at 18 Hz and rolled off 6 db at 20 kHz. You could probably approximate this with analog tone controls. 

Spininvinyl, I agree. When it comes to analog simple is always best and for decade I did exactly what you are doing. Then digital came along, a totally different animal. Now instead of modifying an analog signal you are just changing numbers. Numbers do not have noise or distortion. They are just numbers. A whole new world has opened up. The final product is better than what you can do in the analog world. So much so that I digitize the output of my phonoamp so that is uses the same processor as everything else.