Tone Controls

Several older "straight wire with gain" preamps provided switchable "loops" specifically for use with an EQ or outboard tone controls. In my opinion, this offered the best of both worlds.

If the recording was poor enough to need "help" in terms of correcting tonal balance or other deficiencies, the use of a simple bass or treble control might not be enough. As such, a more advanced processor or multi-band EQ would be more suitable. One could then completely remove said device from the circuit and switch it in as needed. This also added more flexibility due to the fact that you could add / change / upgrade the external processor as one felt the need without having to "dump" the preamp that may have otherwise been functioning perfectly. Sean
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With regard to tone controls, I find that there are a few areas with solutions, and some others that demand new software. For LPs, there are a few vintage pre-amps that offer different EQs, other than RIAA. The Mac C-8 actually allows the user to set the eq with 10 switches. This was developed to accomodate the many early EQ formats.

In the case of a basically Good system with some minor Room issues that tone controls might fix, I would suggest looking into the room issues more closely. I realize that tone controls have a higher WAF/SOAF but if the room problem can be IDed and fixed, one might get a significant order of magnitude of improvement - these could be little things like moving the speaker in/out a few inches, etc.

Sean has a good suggestion vis external boxes connected through loops. There have been a few preamps that offer quality tone controls, Cello, Metaxs?, etc, but they are expensive.

Yes this area is over looked, but it is a trouble some area to solve well.
Good luck.

I'm not positive, but I don't think most people avoid tone controls because of what they do...they avoid them because they involve more circuitry being added into the signal path. Most high-end equipment designs try to have the shortest, most simple signal paths, so they avoid tone controls.

If they're already on your equipment, you might as well use them if you prefer. And you're right...almost all recordings are EQ'd to some point...some quite drastically...especially rock/pop recordings.

I predict tone controls will back in the high end equipment landscape in the next few years. My reasoning is I look at the Cello pre that has tone controls and the new DSP stuff that allows signal manipulation in the digital domain at 30 bit/96KHz sampling. Old analoge tone controls like you are all discussing injected phase distortion and temporal smearing of the signal. Digital domain sampling and DSP manipulation can provide tonal shapping without the bad stuff. We just need to wait till these systems come down from the $12K preamps and parametric equalizers to the $5K high end stuff.

For purists, the thought of deviating from short, unprocessed signal paths is taboo. For the last 20 years tone control-free preamps have been made for them. The reason is obvious: tone controls introduce "grain," colorations, deterioration, or coarse boosts/gains at the wrong frequency, with the wrong slope for the specific adjustment needed (this always seemed to me the key problem with the tone controls on Accuphase amps). This has not stopped a few high-end manufacturers from including high-quality tone controls on their preamps and integrateds (e.g. the Cello Audio Suite) which gives you precise tonal shaping of playback with "very little" loss to the signal. Even so, I've yet to hear an analog tone control bank with "negligeable" loss to the signal. The solution seems to be--as "Keis" put it--to push tonal shaping into the digital domain (negligeable losses, no added coloration) and give the user more precise control over the shaping. This has already been done on the z-systems digital preamp with their Transparent Tone Control (TTC) system. TTC is so precise and uncolored that it will probably change the prejudices purists have about tone controls. Of course, you can use TTC as a tone correction system on a recording-by-recording basis and dial in specific EQs for each recording (then store the setting on one of the 100 presets), but what makes this system exciting is the possibility of achieving a tonally balanced system and listening space. If you use a state-of-the-art calibrated mike and spectrum analyzer, you can refine the sound of your system to virtually flat response. Even the most expensive speakers in the world (the Wilsons, the Avalons, the LumenWhites, etc.) require boosts/gains at certain frequencies in order to yield a flat frequency response. The end results are well worth the hassle of using this system: you will have a tonally balanced system, with greater low-level detail, more immediacy, more extended bass or highs, more openness, an impression of greater speed, an improved spatial presentation, and experience less fatigue. On the forum "Applying EQ to STAX" (Tech. Talk) I describe the use of the z-systems TTC to flatten out the frequency response of the STAX earspeaker system. I have done the same with all of my loudspeakers as well (to achieve neutrality over all hearable frequencies even expensive floor standers need as much as 5 dBs boost at 31Hz, monitors as much as 10dBs boost at 56Hz). Even if this involves the rental or borrowing of a calibrated mike and spectrum analyzer, or complex mathematical calculations to arrive at the proper slope or Q of each boost. This solution seems to me better than coarse analog tone controls or trying to use cables and room treatments as tone correction systems. To conclude, TTC is just another type of purism: not the no-tone-controls purism of the 1990s, but the DSP-tweeked-neutrality purism of the 21st century.