I'm hoping our audio gurus will chime in on this.

I ran into this link over on the speaker forum. If I'm reading the article correctly, it's talking about "in-room" frequency response (not just equalization), and it suggests that a flat in-room response may not yield the best sound.

What do you guys think? Is this for real?

http://www.hometheatershack.com/forums/rew-forum/96-house-curve-what-why-you-need-how-do.html

I'm too lazy to read it :D but the point of a house curve is to get a more equal sounding frequency response to your ears. Your ears are more sensitive to higher frequencies so if you eq flat, higher frequencies are going to sound more pronounced than the lower ones. Generally if I remember correctly (been a while since I played with my BFD), you want to eq flat to about 30 hz and then eq in a 5db drop to around the xover point. This would sound more "even" when watching movies. This does not apply to music however. I have a separate curve set up for movies and music.

A common mistake is for people to apply Audyssey MULT EQ to a THX RE-EQ.

Well, if we are trying to reproduce the cinema experience in our homes then the House curve used in theaters would be appropriate,no? Me personally I would say dont use it, it sucks the life out of the sound if you have a capable system, but if you insist on recreating that cinema feel then the smaller XCurve would be used....here is the definition of the X Curve per SMPTE standards used in Cinema.

x curve Stands for "extended," as opposed to the "N" (normal) curve, which is the same as the Academy Curve. The "X" curve is also known as the "wide-range curve," and is codified in ISO Bulletin 2969. Specifications call for pink noise, at listening position in a re-recording situation or two-thirds of the way back in a theater, to be flat to 2 kHz, rolling off 3 dB per octave after that. This curve is found in all motion picture theaters and re-recording stages worldwide.

The "small-room X curve" is designed to be used in rooms with less than 150 cubic meters, or 5,300 cubic feet. This standard specifies flat response to 2 kHz, rolling off 1.5 dB per octave after that. Some people use a modified small-room curve, starting the roll-off at 4 kHz, with the response down 3 dB per octave thereafter.

And we're talking about measured in-room response here, right? So this stuff would apply even to our fancy, acoustically treated home theaters?

I'm curious what Dennis, Bryan and others have to say about this.

And we're talking about measured in-room response here, right?

We hope so, applying a EQ curve without taking measurements would be pointless IMO.

Typically DVD audio is re-mixed from the cinema release version. This means, to a large degree, that a cinema X curve, or modification thereof, is probably not the right way to go.

A lot of research has been spent on endeavoring to understand what may be involved in a pleasant sound. As opposed to the headache inducing 4 KHz laser beam to the skull!

Some of this research looks at the direct / indirect ( or reverberant) ratio. That research is still ongoing.

The final answer is of course how it sounds to you. As acoustic treatment begins to be deployed in a space, the particulars of how the direct sound should be tailored will be a function of the treatment and the transducer characteristics.

So play with it and let us know how it shook out for your room/system.

As acoustic treatment begins to be deployed in a space, the particulars of how the direct sound should be tailored will be a function of the treatment and the transducer characteristics.
Oops! Treatment or not, it all depends on the room and transducers :)

Jeez - I feel like I am stuck in Ground Hog day or something.

Along with all else, your processing will play a distict role in the sound. The ambience extraction and reproduction thereof will impact both the timbre of what you perceive and your enjoyment.

So, to the OP - Yes, house curve is very real.

I'm too lazy to read it :D but the point of a house curve is to get a more equal sounding frequency response to your ears. Your ears are more sensitive to higher frequencies so if you eq flat, higher frequencies are going to sound more pronounced than the lower ones. Generally if I remember correctly (been a while since I played with my BFD), you want to eq flat to about 30 hz and then eq in a 5db drop to around the xover point. This would sound more "even" when watching movies. This does not apply to music however. I have a separate curve set up for movies and music.


But doesn't the person mixing the audio have ears as well and therefore the mix itself should be "pre-compensated" for?

Now, I can see the point of a house curve to compensate for not listening at reference levels since the ears perception of low frequencies changes based on volume. If you look at equal loudness curves, the difference between a 40hz and 1khz tone on the 70db curve is around 20db. But on a 90db curve it is only 14db. I think this is the reason a lot of people enjoy their sub boosted a few db, it compensates for not listening at reference level.

Thanks for all the info, guys.

I was hopeful that Dennis (or someone like him) would chime in to let us know if the master gurus around here are designing rooms with the intent to make them function according to a particular curve (EQ included, of course) or if, to these guys, flat response is the goal.

The goal is to reproduce what's on the tape/cd/dvd. We do not design to emphasize any portion of the spectrum. The overall target decay curve of the room is designed based on the room size and what it's to be used for.

Bryan

The goal is to reproduce what's on the tape/cd/dvd. We do not design to emphasize any portion of the spectrum. The overall target decay curve of the room is designed based on the room size and what it's to be used for.

Bryan

So the golden ideal is a measured, in-room response that's as close to flat as possible?

See, the reason I asked the question here instead of responding to the folks in the speaker forum is because I know that in this forum, we're primarily concerned with room design, and I've heard many of the experts in this forum say things that are frequently contradicted by the speaker guys over there, probably because they're not as aware of some of the room design issues.

So does that mean that there is no point in trying to design a room that uses a particular curve (either through acoustic treatments or EQ)? Bryan, if you get a chance to read those long-winded articles, I'd be very interested if you have any commentary on the basic theory behind them and how it might (or might not) apply to rooms like ours.

The argument that the goal should be to faithfully reproduce the recording is also addressed (and countered) in the article. I figure you're right, just interested in some thoughts about it.