The Pros and Cons of Tone Controls

To Doug Schneider,

I was wondering if you would comment on why today's audiophiles are so negatively against tone controls. In the past, many high-end products, such as Marantz and McIntosh (who still have them, I believe), had them, but these days they are held in contempt by most. I find this puzzling, since most listening rooms are far from perfect and could probably benefit from modest EQ corrections. These days, many entry- and mid-level products, such as affordable integrated amps from NAD, Cambridge Audio, Marantz, Rotel, and others have them, yet most high-end products don't. And most reviews of these integrated amps that do have them seem to want to discourage buyers from using them.

I work in retail, which is extremely low paying, generally, yet I have hobbies which can be expensive (photography, audio, and guitars), so I'm always looking for the best available products at the lower price points of these products. My personal experience with lower-cost bookshelf speakers from reputable manufacturers is that some have a sonic signature that cannot be altered by tone controls, but some can be transformed from good to exceptional by a modest boost or cut of bass and/or treble. Wealthy audiophiles instead seem to want to change whole component or add expensive cables to alter the tonal balance of their systems (which are therefore, in effect, tone controls), which I find foolish, to put it mildly.

Am I crazy, or are they? Your thoughts on this would be welcomed, since you are far more honest than most audio journalists, who are often afraid to offend by telling the truth. Sorry for being so long winded.

Best wishes for the holidays,
Doug Mencoff

You’re not crazy at all. This is a great question that should really be answered with an entire article, since there are so many aspects to it; in fact, I will ask our main technical writer, S. Andrea Sundaram, to consider it. Right now, I’ll just skim the surface and give my two cents' worth.

I think that traditional analog tone controls have gotten a bad rap for two main reasons. One is that the circuitry used sometimes deteriorates the sound even when the controls are left in a “flat” position. For example, my Nakamichi AV-10 receiver has tone controls, as well as a switch to defeat them. The sound is noticeably cleaner and clearer when they’re defeated. I have no idea why, but I suspect the tone-control circuitry is adding some kind of distortion. As a result, any improvements that might be had using the controls are outweighed by the loss in fidelity. The same sort of thing tends to happen with analog equalizers, which are similar to tone controls but usually have a lot more functionality and flexibility. So, that loss of fidelity is one of the major downsides of tone controls (and equalizers). But if the circuitry is transparent, then that’s a moot point, which it tends to be in some of the upper-end gear like McIntosh.

The other reason is that audiophiles have been taught that perfectly flat frequency response for electronics is a good thing, and that anything that deviates from that is bad. Tone controls obviously create a deviation from linearity, so the general thinking is that they’re bad. In a perfect world, that advice would probably be good, since neutrality is what we’re generally after, but the speakers most people use and the rooms they’re used in are often far from perfect -- electronics are easy to make flat, but speakers and rooms aren’t. As a result, imperfect speakers and rooms can use the help that tone controls give. Unfortunately, as you pointed out, audiophiles often resort to using cables as tone controls, which is a foolish thing to do, since it amounts to correcting the problems of one or more things with another one that’s not really designed to do that job. If some modest frequency-response adjustment is necessary, high-quality, transparent-sounding tone controls would be better to use. That doesn’t mean every preamp or integrated amp should have them, but that it might not be a bad thing if they did. If more than modest adjustment is needed, then maybe new speakers or some room treatments are in order -- certainly not new cables or some other tweak.

As a side note, I think it’s worth mentioning that tone controls are being reintroduced to audio in a new, more advanced way: room-correction systems. Most room-correction systems function like very advanced equalizers, but they work in the digital domain, which is a good thing, since far more manipulation can be used without much, if any, loss of fidelity. One of the best systems on the market is from Anthem: ARC (Anthem Room Correction). ARC comes built into their preamplifier-processors and receivers and works like a charm. Most people who use ARC find the pros of it far outweigh any cons. . . . Doug Schneider