In the audio realm, you can go to great pains to get a ruler flat response from your system, i.e. equalization, room treatments, speaker selection placement, etc.

The only limit is how "calibrated" you want to get. There's always another level you can take it to if you have the patience and $.

After all this, it has been discovered that you need a "house curve" if you want it to sound good. In other words, calibrate til the cows come home, but then tweak it by ear until it sounds good, because flat doesn't sound good. Everyone's "sounds good" will depend on their gear, room, sources, ears, tastes, etc.

However, there does not seem to be a similarly accepted idea for video. A perfectly calibrated display, whatever that is, is considered" perfect."


I have not had a "professional" calibration, which I'm sure would do a better job than me and my DVE disc. Still, I found the calibrated color to be too saturated. It may be calibrated, but it does not look real to me. So I lowered it a bit.

Thoughts?

Greetings

Kind of assumes you actually did it right ...and there is so much more to calibration than setting the color saturation.

See the thread at the top ... root fundamentals of calibration.

Regards

Greetings

Kind of assumes you actually did it right ...and there is so much more to calibration than setting the color saturation.

See the thread at the top ... root fundamentals of calibration.

Regards

And your post assumes I did it wrong.

I've seen that thread, and yes I know there is much more than saturation. That was a simple example. You missed the point.

Greetings

There is also the possibility that color saturation and tint don't work right on your tV ... which happens ... also the filter might be wrong ... which also happens ... lots of other possibilities.

But if your intent is to drag up the argument once more about how standards don't matter ... you should take it somewhere outside a calibration forum area.

regards

Greetings

There is also the possibility that color saturation and tint don't work right on your tV ... which happens ... also the filter might be wrong ... which also happens ... lots of other possibilities.

But if your intent is to drag up the argument once more about how standards don't matter ... you should take it somewhere outside a calibration forum area.

regards

Yes, those are possibilities. Perhaps that is the case. We can leave my TV out of it, although it is regarded as a "pretty good" one. (SamsungPN50A550) I'm sure it is not top of the heap.

Not "dragging up the argument" - that is precisely not at all my point. Perhaps I did not make the point well enough in the original post.

I was trying to convey the concept of the house curve that is subjectively applied AFTER an audio calibration in order to make it "sound good," and that there does not seem to be an analogous concept that is widely accepted for video.

You flatten out an audio response with various technical adjustments, and then you fudge it to make it sound right. This is similar to what I did with the saturation.

I realize that audio is not video, and we are talking about psychoacoustics and perceived flat response in audio, not video. They are not exactly equivalent. The point is it is a subjective adjustment to make it "sound right."

I find it interesting that there is no analagous concept accepted for video. It is either calibrated or not, although there is still variation and error there as well. There seems to be no allowance for the individual viewer however.

Greetings

Preference comes in if you don't like what calibrated represents ... and there is no crime in that. Set the TV to what pleases you and go on with life.

You know what the goal of image calibration is ... but if your TV cannot get there ... then some compromises have to be made ... that is life.

We can't get to perfection ... no one can ... but on many of these sets today ... we can get pretty close.

2+2=4 ... no one says you have to like it there ... maybe 9 works better for you ... which is okay ... but that type of subjective argument is best taken outside of a calibration forum.

regards

I think with both audio and video the purists share a similar idea, calibrate the display to meet the calibration standards and keep EQ and other nonsense out of the audio chain to keep the signal as pure as intended. If done right in the first place the source should be as good as it can get on a well setup audio or video system.

And your post assumes I did it wrong.

I've seen that thread, and yes I know there is much more than saturation. That was a simple example. You missed the point.
He didn't miss the point. The premise for your (subjective) argument is the fact that the results of calibration for saturation presented an unrealistic image. One must first ask then, was it done right? Though i am in no way insinuating that it was entirely your fault, but i am saying that dve's method for working out saturation is flawed in many ways. Its more of a very rough guide than a method of true calibration. Dve works off of the blue filter, however many display technologies, and many displays within those technologies have their blue spectrum vary a bit, because of this it is impossible to make a single blue filter that works accurately on all sets. That and is does not guarantee your saturation for each primary is linear.
But even putting that aside, imo, both audio and video have very set standards which should be met. However, not all subscribe to this idea, but that is because they usually lack the understanding of why.
For video, if you're not calibrated correctly, you more than likely will see less detail in the image, possibly not have the must optimal black level that is possible by the display... and many other things.
With audio, you must think from an engineering perspective. If you're building a device to playback recorded audio, what kind of a response would you give the device? Answer, a flat one! If you record a sound, and play it back, it will be played back equally (or as close as we can get) on a linear frequency response system. If you miss calibrate it and possible, lets say, boost the lower frequencies, then the reproduced audio will now be incorrect and not the same as when it was recorded.
Now, it is true that no one has to abide by these rules if they don't wish too. If you don't like what calibration gives, that is fine. But imo, it is useless to argue such a thing when your position is as subjective as it is.

And your post assumes I did it wrong.

I've seen that thread, and yes I know there is much more than saturation. That was a simple example. You missed the point.

And your original point assumes that "real audiophiles" believe in EQs and house curves.

Micheal is absolutely correct, calibration is about the science of what is correct and the art of compromising what you can do within the limits of the equipment.

If you believe there is an additional step to correct for your preferences that is okay, but it is no longer calibration and therefore not a discussion for this forum.

One other thing to consider is that one many displays it may simply not be possible to get every parameter right on spec so you have to decide what you want to trade off.

As a specific example, if you had to trade off a perfectly flat greyscale vs a perfectly smooth gamma curve, which would you choose?

It seems plain to me that the original poster is looking for a way to adjust his video equipment to compensate for variations in his room. Just as audio gear might have been designed to perform well in an anechoic chamber but then needs to be adjusted yet for the listening environment of the user. Viewing environments affect how a display performs regardless of whether or not it has been calibrated by instruments to a reference standard.

I'm a bit surprised those responding to the OP haven't addressed this. There are "sticky" threads at the top of this section of the forum which address the viewing environment component. Room acoustics require adjustment of sound equipment. Viewing environments require adjustments beyond instrument readings due the human perceptual factors. This should not be unfamiliar to anyone well versed in imaging science and display industry standards and practices.

Christo, this article may satisfy your query: http://www.cinemaquestinc.com/ive.htm . Let us know if it does.

Best regards and beautiful pictures,
G. Alan Brown, President
CinemaQuest, Inc.
A Lion AV Consultants Affiliate

"Advancing the art and science of electronic imaging"

It seems plain to me that the original poster is looking for a way to adjust his video equipment to compensate for variations in his room. Just as audio gear might have been designed to perform well in an anechoic chamber but then needs to be adjusted yet for the listening environment of the user. Viewing environments affect how a display performs regardless of whether or not it has been calibrated by instruments to a reference standard.

I'm a bit surprised those responding to the OP haven't addressed this. There are "sticky" threads at the top of this section of the forum which address the viewing environment component. Room acoustics require adjustment of sound equipment. Viewing environments require adjustments beyond instrument readings due the human perceptual factors. This should not be unfamiliar to anyone well versed in imaging science and display industry standards and practices.

Christo, this article may satisfy your query: http://www.cinemaquestinc.com/ive.htm . Let us know if it does.

Best regards and beautiful pictures,
G. Alan Brown, President
CinemaQuest, Inc.
A Lion AV Consultants Affiliate

"Advancing the art and science of electronic imaging"
I could be reading his post wrong, but i don't think that is what he is attempting to address.
From what it seems, he is calibrating the audio and video within the correct environment. But he is talking about applying a "house curve", in otherwords tweaking it by eye/ear after doing a correct calibration to adjust it to the (keyword) "tastes" of the individual. Which, as others have said, he is more than welcome to do so, but then it is no longer called "calibration".

...Viewing environments require adjustments beyond instrument readings due <to> the human perceptual factors..."

That's pretty much what I was trying to get at, because as I understand it it, is exactly "human perceptual factors" that lead to the use of house curves for audio EQ, which are designed for achieving perceived flat response.

So the intent of my post (which has clearly failed miserably) was to question if there are, in a general sense, analagous concepts for video - adjustments to otherwise calibrated video to provide the video equivalent of a perceived "flat" response.

I'm not trying to redefine what is or isn't calibration. No need for everyone to rush in to the defense of calibration with sabres rattling.

Typical adjustments to compensate for varying ambient lighting conditions include: LCD panel back light level, white level (contrast), black level (brightness), gamma, etc. Otherwise, it's really the room conditions which have to be 'adjusted,' rather than the display. This would be analogous to the use of acoustic treatments in a room to compensate for audio problems that cannot be resolved effectively with electronic adjustments.

Video and audio adjustments aren't directly comparable, Cristo. Overall, audio is far more dependent on in-room conditions than video, IMHO. Case in point: if I take an audio system that has been properly set up for great sound in one room and move it lock, stock, and barrel to another room, the complete setup will have to be redone. However, if I move a calibrated display such as a plasma or LCD flat panel from one room to the next, when the display arrives in the other room, it is still calibrated. I may have to adjust room lighting or the display's brightness and contrast a bit, but most of the display's calibrated settings such as grayscale, color decoding, etc., won't need to change. GeorgeAB made the point in the post above, I think. Video calibration is primarily innate to the display device, while audio calibration involves the room probably even more than the electronics.

So the intent of my post (which has clearly failed miserably) was to question if there are, in a general sense, analagous concepts for video - adjustments to otherwise calibrated video to provide the video equivalent of a perceived "flat" response.

Like Rolls-Royce commented, the room affects audio far more than video. The main thing that affects video calibration is light in the room, because perception changes depending on such things as relative light levels. The most basic adjustment for video is that you might have to raise or lower black-level (brightness) depending on how much light you have in the room. An ideal target for gamma, or how light increases from black to white, might also vary depending on room lighting - but many displays don't offer a way to adjust gamma.

As far as the "house curve" bit goes, one comparison for video is that some people like primaries that are over-saturated. For example the Hdguru.com review of the Pioneer plasmas say that he personally prefers the more inaccurate colorspace. He admits that the colorspace he likes is less accurate, but that's what he chooses to use.

Another similar comparison of where personal preference rules over accuracy would be a blue-ish grayscale. Many people will prefer more blue in the grayscale than what is recommended as accurate for reproducing an image. If you measure what people judge by eye as white, generally it will tend more toward blue than the standard. The room might affect this judgement, but generally TVs ship with a very blue grayscale. If people found the tilt toward blue offensive then the TV makers wouldn't ship them that way. Of course the tilt toward blue in the default settings might have to do with the expected lighting of showrooms.

The display itself is only one link (granted, a primary one) in the chain. Far too many people don't think beyond the display when considering calibration. Complete adjustment must take the entire signal chain and system into account, including room conditions and human perceptual factors.

Two foundational and seminal documents in traditional display use and calibration are: SMPTE RP166: 'Critical Viewing Conditions For Evaluation Of Color Television Pictures'; and SMPTE RP167: 'Alignment Of NTSC Color Picture Monitors.' They are considered companion documents and each make reference to the other. Note which document was published first.

Whether audio is more or less room dependent than video is irrelevant. Genuine electronic display alignment cannot ever be divorced from viewing environment issues and human perceptual factors considerations. When some practitioners do, either out of ignorance or negligence, consequences to overall performance can be assured.

Cristo did make reference to "ears, tastes..." in his original post. It bears repeating that, in the video industry, universal standards are implemented to preserve the program producer's vision and judgment all along the signal delivery chain. "Looks good" is authentically defined by the originator's approval of the image on a reference monitor, in controlled viewing environment conditions. However, in circumstances where a consumer's equipment and/or viewing conditions fail to provide ideal performance, compromises must be intelligently made. Defaulting to individual image assessment judgments is unavoidable in such cases. If image fidelity is the primary goal, such judgments should be made only after system calibration is attempted. The foundation for such judgments should still be experience with display behavior and image quality on monitors that have performed correctly.

That's pretty much what I was trying to get at, because as I understand it it, is exactly "human perceptual factors" that lead to the use of house curves for audio EQ, which are designed for achieving perceived flat response.

So the intent of my post (which has clearly failed miserably) was to question if there are, in a general sense, analagous concepts for video - adjustments to otherwise calibrated video to provide the video equivalent of a perceived "flat" response.

I'm not trying to redefine what is or isn't calibration. No need for everyone to rush in to the defense of calibration with sabres rattling.
The essence of the issue here is what I've highlighted. The Society of Motion Picture and Television Engineers (SMPTE) have defined standards for the presentation of both video and audio. These are relatively rigorously defined, and even have provisions for the effects of things like the illumination provided in-theater of exit signs.

Where audio diverges quite a bit from video is in the translation to a home set-up. Ironically, while there are defined standards for what a mastering room set-up is like for theatrical presentation, there are not equivalent hard-and-fast standards for something as foundational as speaker locations (there are something like 17 allowable speaker topologies allowed!!). There was an article published a bit ago from some people at DTS that goes into this more. Google is your friend (too lazy to pull it for you).

So, given the above, it is understandable, then, that there is a lot of confusion in the consumer space about what the target actually is. Consider, for a moment, trying to explain the concept of a decibel. Then try explaining the difference between dBA and dBC. People aiming for a "flat" response are making choices and assumptions about what target they should be aiming for without any real knowledge. For music, this is akin to the Wild West. Lots of opinions and lots of space for everyone to disagree, but lots of people seem to go looking for a fight (e.g., were your speakers voiced with a "BBC Dip" or not...). For movies, though, there is some help...

More than 25 years ago, SMPTE decided on what is known as the "X Curve" (http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/Dolby_The%20X-Curve__SMPTE%20Journal.pdf). Because of the challenges inherent in hitting a defined acoustical target with a theater that deviates even slightly from the assumptions embedded in the standard, consumer theatrical presentation can vary substantially from this standard. However, the targets used in the mixing studio are very much doable in-home (though it may not be aesthetically pleasing).

If your home acoustical environment ultimately matches the environment that the movie was mixed in, then you have a pretty good shot that the movie will sound right (barring some of the issues with speaker topology noted above). Otherwise, then it just won't. Imagine, if SMPTE mixed to a flat response, but then someone had set up a tweeter with a 6dB/octave rise from 2.5kHz and up, then a movie would still sound overly bright. Hence you have the birth of THX processing in the home. Tools like TrueRTA, RoomEQ Wizard, ARTA, etc. are your friend here.

This is a pretty big topic unto itself, and it really belongs more in the audio section of the forum, but hopefully this helps.

Hope this helps!

Bill

My problem with his post is that he is talking about calibrating the audio like crazy to get it dialed in... then using a house curve to get his flat response. The problem lies in the fact that if you're calibrating the audio system correctly, you're already taking in the environment variables into consideration. Hence, at the end of the day, there is no need to apply a "house curve" since it is already built into your calibrated settings. Hence my confusion when it stated calibration then applying a house curve.
This whole subject is different when we talk about video though. There, even the colors of nearby walls can affect our actual perceptions of onscreen color that a meter won't pickup. The best way to deal with this, is to design the room to be of neutral color to begin with imo.

because as I understand it it, is exactly "human perceptual factors" that lead to the use of house curves for audio EQ, which are designed for achieving perceived flat response.

Other than non-linear frequency response due to volume I have no idea what you're talking about but it sounds suspicious. If you mean "what should I do if my display is in front of a brightly illuminated green wall" or if runway landing lights are shining into your TV room then those are well known issues with pretty straightforward solutions. They don't typically involve changing the display.

On the other hand invariably watching dark content in a bright room will probably motivate a change in display settings the same way you might turn up the stereo to compensate for the aircraft on that runway. Both of those solutions are sub-optimal abient light or sound sensors notwithstanding.

My problem with his post is that he is talking about calibrating the audio like crazy to get it dialed in... then using a house curve to get his flat response. The problem lies in the fact that if you're calibrating the audio system correctly, you're already taking in the environment variables into consideration. Hence, at the end of the day, there is no need to apply a "house curve" since it is already built into your calibrated settings. Hence my confusion when it stated calibration then applying a house curve.
The issue is that people erroneously assume that a "flat" frequency response is "accurate" with respect to movies, and they work hard to neutralize the room acoustically. Then, they realize it sounds like garbage, so they apply additional processing (aka "house curve"). The fundamental misunderstanding is that movies are mixed such that they take advantage of the X-curve, which is hopefully a doable/repeatable/standardizable acoustical environment for theatrical presentation.

This whole subject is different when we talk about video though. There, even the colors of nearby walls can affect our actual perceptions of onscreen color that a meter won't pickup. The best way to deal with this, is to design the room to be of neutral color to begin with imo.
Actually, the opposite is true. You can generally fix the visual environment of a room with some paint, some window treatments and equipment that doesn't have overly bright LEDs/VFDs/etc. From an acoustic perspective, everything in the room affects the sound, especially the geometry. Fixing that, short of re-orienting some things, can lead to major reconstruction.

As I said, above, this thread really belongs in an acoustical calibration forum, but we really don't have one here (theater builder forum, maybe? Audio theory, setup and chat?).

Bill

As I said, above, this thread really belongs in an acoustical calibration forum, but we really don't have one here (theater builder forum, maybe? Audio theory, setup and chat?).

Bill

I think it's pretty clear Cristo is talking about video not audio [emphasis mine].

analagous concepts for video - adjustments to otherwise calibrated video to provide the video equivalent of a perceived "flat" response.

I think it's pretty clear Cristo is talking about video not audio [emphasis mine].

He was indeed, but he did use audio as his comparison. The thrust of most of the posts (mine included) was to explain that there really aren't the same types of "house curve" perceptual adjustments needed with video, and why this is so.

He was indeed, but he did use audio as his comparison.

I was responding specifically to Bear5k.

The reason for using a "house curve" in audio is because the recording engineer listens to the mix on "flat" monitors and tweaks the sound to be enjoyable on "normal" speakers.

If you set your speakers to play perfectly flat and your room is in a anechoic chamber it should sound exactly as the engineer wanted it to.

Unfortunately most rooms and systems are not "flat" or is you tweak for a flat sound the space in which the sound is played will cause interactions with the tone or the sound is simply unpleasant sounding and unnatural because all of the sounds are just as loud as the next without the gaps in frequency seen from musical instruments or even sounds in nature. So you boost some frequencies to "smooth" out the sound.

A similar effect is seen if you use a "daylight" light that produces the same light as the sun thought out the spectrum evenly thus having a high CRI or Color Rendering Index. the light will look very harsh to most people and too reveling. Even though the light being output is much more akin to "real" sunlight people are used to regular light bulbs that produce very "warm light"

The two "flat" ways of producing their respective emissions are more accurate but not always pleasing to a observer.

That said Gamma is a method to control to way video is output taking into account for viewing conditions, albeit done with a fixed standard assumed so we get a proper picture when when calibrate to said standard.

Depending on the viewing environment's lighting,quality of light, color of the surroundings and the displays ability to produce images, calibrating to too high or too low a Gamma will provide a less that idea image because the human eye can and will adapt based on those things.

Your ears don't adapt in the same manner. They are pretty much always "on" , it is more a matter if you are listening for certain things more carefully or not that will determine what you hear or hear well. That is why it is subjective.

The cool thing is that light is easy to adjust simple because we can see it and humans primarily take in information visually so to fix a environment's lighting is often much more simple than adjusting for sound. Sound is mechanical energy so it interacts with the physical surroundings as part of being transmitted but light interaction with a environment is interrupted and processed by our brains. It is kind of like built in signal processing being constantly done on everything we see so if we make the viewing conditions more neutral we can calibrate to a standard to get closer to how the video/film was intended to look.

A "house curve" is just a way to get better results instead of listening in a anechoic chamber, its not perfect or a exact standard but neither are any human made thing and for some it works well enough to be worthwhile and others will go beyond that either because the need to or simply want to.

The reason for using a "house curve"
I think we're conflating enough things here that we're failing to have a meaningful conversation. To try to speak to the OP I'll suggest that bias lighting may be the closest thing the external equalization applied to sound to adjust for psychoacoustic effects and neutral backgrounds the equivalent of acoustic treatments.

I'm not going to try to draw any comparisons between something like gamma and "loudness".

For those of us who prefer definition of terms and associated assertions to be backed up with authoritative industry documentation, this will be of value:

"The X curve now has nearly a quarter century of use and has absolutely acted to help interchange in the industry. Combined with level standards, and de facto industry standards such as speaker directivities, the whole film industry has benefited without a doubt. Problems linger in applying the standards uniformly due to different methods of measurement. Also, when heard over a modern flat loudspeaker in a small room, program material balanced on an X curve monitor sounds overly bright. That's because the original experiment that set the curve was made many years ago, without the frequency range available from today's components. This is not too important because, so long as everyone agrees to use the same curve, then the response sounds the same to the mixer on the dubbing stage as to the audience member in any auditorium. Interchangeability of X curve material with home video can be handled with a simple re-equalization. The ATSC television standard recognizes the differences, sending a flag that tells receiving equipment whether the program material was balanced on an X curve monitor, or on a flat monitor in a small room, and home equipment can take appropriate action to re-equalize the program accordingly." 'A History of the X Curve' Surround Professional, January 2000, Volume 3, Number 1, by Tomlinson Holman, http://www.micasamm.com/publications/surround_0100b.htm .

The full article is not long and should make clear the OP's use of the term "house curve." As in movie sound reproduction, video program image reproduction is also affected by equipment/measurement/room/audience perception characteristics. Imaging industry standards and recommended practices describe system design/setup procedures and methods that are legitimately analogous to "house curve" audio system tuning. For those wanting documentation on the video viewing environment side of the issue, I can refer you to:

SMPTE RP166-1995: ‘Critical Viewing Conditions For Evaluation Of Color Television Pictures’
ITU-R BT.710-4 'Subjective Assessment Methods For Image Quality In High-Definition Television'
ISO 17121:2000 'Cinematography -- Work stations used for film and video production -- Requirements for visual and audio conditions'

Best regards and beautiful pictures,
G. Alan Brown, President
CinemaQuest, Inc.
A Lion AV Consultants Affiliate

"Advancing the art and science of electronic imaging"

The full article is not long and should make clear the OP's use of the term "house curve."
Normally I'd just say "whatever" but I really think (and not out of malice) that the OP means something other than complementary equalization and I think "house curve" in one's home is inspired by "loudness" not by X curve de-emphasis. Certainly the weight given to sub-woofer management in the popular literature suggests that.

Now this statement
"human perceptual factors" that lead to the use of house curves for audio EQ, which are designed for achieving perceived flat response.
suggests that your interpretation (and Bill's take) might be where Cristo was going but then further statements seem to contradict that. I'd prefer if Cristo was a bit clearer then we might agree about what we're talking about even if we draw different conclusions.

In any case, things, as always, are informative in various ways.

Normally I'd just say "whatever" but I really think (and not out of malice) that the OP means something other than complementary equalization and I think "house curve" in one's home is inspired by "loudness" not by X curve de-emphasis. Certainly the weight given to sub-woofer management in the popular literature suggests that.

Now this statement

suggests that your interpretation (and Bill's take) might be where Cristo was going but then further statements seem to contradict that. I'd prefer if Cristo was a bit clearer then we might agree about what we're talking about even if we draw different conclusions.

In any case, things, as always, are informative in various ways.
I guess where I was taking it was the fundamental error in the OP's premise: that a "flat" in-room response is the desired target for film presentation. The article linked in my post and the one George linked both talk about what the actual target ought to be (X-curve).

On the video-side, the thing that comes fastest to mind is "red push" in a poorly/incorrectly/inaccurately built color decoder. TVs being set to compete with each other at 9300K had to have other manipulations in them to get flesh tones to look right, hence the birth of "red push". While red push was a desirable thing if you didn't know any better (e.g., knew nothing of D65), it was an attempt to solve a problem at the wrong place, much like a "House Curve" would if you had a perfectly flat room and speakers.

Now, if you had a flat room and speakers and then applied a "house curve" to get to an in-room response that mimicked the X-curve, then you would be listening to the movie as it was intended -- barring a mismatch between your speaker layout and the way the DVD/Blu Ray re-mix was performed.

Bill