Toole and why I like Tone Controls


In another thread I was pointed to a really excellent paper by Dr. Floyd Toole (he doesn't use the Dr. but it is well earned) on getting to neutral.

So I want to go back with a little history. In all of audio reproduction theater sound reproduction is among the most rigidly controlled areas of audio. From the needs of Dolby Surround playback, to introduction of acoustic decay requirements introduced by THX, and more, the attempt to deliver a uniform theater experience has been a subject of serious effort by many, and continues to be so.

That's in sharp contrast to consumer music.

So while this article focuses heavily on theater sound, it also touches on just how difficult it is for even theater sound experts to get to neutral. If they can't do it, imagine how hard it is for music!

And, yes, I'm going to hijack Dr. Toole's paper to plug tone controls. With all the guessing that goes on, not using tone controls, and not having great tone controls to use is folly.  Quote me. I said FOLLY!

http://www.aes.org/tmpFiles/elib/20200201/17839.pdf

Also, personal request, if anyone knows how I can get in touch with him and be a fan boy, please let me know. :) I'd love to hang with him, and it turns out he's a local.
erik_squires

Showing 1 response by audiophilenm

In my experience the best tone control is no tone control.

Ideally, the best tone control you can have is a properly calibrated room and system. If this is your situation, you'll have as close to an ideal response curve as is practical. No tone control necessary. Though, with some terrible recordings you may wish you had one. Unfortunately, that's our problem, and the recording engineer's fault. I've learned to live with that, but I understand the desire to make a bad recording sound good...
When I first started out, I used to think flat response curve was my goal, and couldn't figure out why it looked great on the screen and sounded like crap in the room. I didn't trust my hearing, as I hadn't yet learned to listen, and I hadn't learned to respect the 50/50 balance between measurements and listening as I do now. After 13 years of calibrating I'm 100% sure that a dead flat response curve is not even close to the holy grail. No room here to discuss what is ideal, but using DSP, EQ or tone controls to get as close to a flat response curve as possible is almost always a fool's errand.

I've been called in to "fix" many systems that were calibrated using Trinnov, Audyssey, and manufacturer's proprietary auto EQ systems including Krell and JL Audio. None of those systems approach the quality of sound you get from properly, physically, calibrating your system - the room's acoustically acceptable, the speakers and listening position are properly coupled to the room, all participants in the system are respecting and working synergistically with physics. Step 1. Always!

After that, DSP, EQ, and tone controls can be used like a pinch of salt - not a fistful or a backhoe full of salt - to knock the tops off the most egregious problems. That's it! No more! And no more than 5dB of attenuation...preferably no more than 2dB. If your setup requires that you mash the tone control or max out the DSP it's time to set everything at "0" and start over. Parametric EQ is best, with a "Q" of 0.7 being ideal, and only nudge what needs to be nudged. If you have a 20dB hump in your response curve at 32Hz, don't EQ it! Find out what the hell is causing that nightmare and fix it. It's likely a loose sheet of drywall or a floor resonance.

The more tone control or EQ you use the more mangled the phase becomes, and although it's hard to pickup on a meter, your ears and brain know that something's not right. This is a problem in the time domain which affects frequency. That's when your brain starts running its' natural hardware and software, trying to reconcile what it hears with what it knows that should sound like. Our own internal EQ. And that's when listener fatigue starts to kick in, and you may find that after 30 minutes or so you can't wipe that look off your face, you know the look that you get when you bite into a lemon. Not the look that most of us are after...

Go easy, and fix the problems at their source. Then, light on the tone control if necessary. And if you absolutely must, have a tone setting (+bass/-treble) for that rare occasion when you're listening to an 80's CD of Mike and the Mechanics. Good luck!