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EQ of the X curve
#1
Hello!

Cinemas and mixing theaters have a non flat frequency response. The sound systems are allignment to create a torwards higher frequencies falling curve, the so called X curve.
This means that every soundtrack from the cinema is optimised for this reponse and not for a flat response which most hifi / home speakers have.

When cinema sound is remastered for home use, this is mostly equalised by the studios. At the beginning of Laserdisc and DVD this was not the case and THX added a function
called Re-EQ, which did reduce the heights for cinema soundtracks not sounding brighter as it was meant to be.

Some projects here are using soundtracks from cinema, like the DTS cds. My question is therefore, if it is common in most projects to compensate the X curve or not?

Thanks!
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#2
I always thought the X-curve was applied during playback, ie in the 'B chain'.
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#3
This is true, but the Rerecording Engineer, who does the mix is listening to a system with that response. So to say he is mixing against the curve.

For example: He is importing some recorded music into his project and he is missing some heights when listening in this mixing theater. After he has increased the height in level they sound exactly right on his system with the X Curve applied. If this system would be changed to have a flat response it would sound to bright.
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#4
I see you've started one already, cool beans. Maybe we can get DoomBot in here to discuss how he works with audio?

He's been doing great work and suggestions and opinions from other angles is always great to make things better if they can be.
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#5
There's an interesting thread here http://www.film-tech.com/ubb/f1/t008286.html on such curve.
AKA thxita on OriginalTrilogy
I preserve movies as they first appeared in Italy.
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#6
There are a lot of rumors and wrong information why the x curve was implemented. If you really want to know something about it, I suggest this article: http://www.aes.org/tmpFiles/elib/20170705/17839.pdf

What would be interesting is to compare the spectrum of a movie soundtrack for cinema and the same of a blu-ray to see if any filtering was applied to compensate the x curve.
An interesting article showed recently, that the recording engineers get used to the dull sounds of cinemas and are not compensating this in their mix. If this is the case, no eq would be needed when converting cinema to home sound.
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#7
(2017-07-05, 07:49 PM)Tomlinson Holman Wrote: What would be interesting is to compare the spectrum of a movie soundtrack for cinema and the same of a blu-ray to see if any filtering was applied to compensate the x curve.

I'm not an audio expert, but you seems so; why don't you get a project that includes a Cinema DTS track, make the comparison, and write your conclusions here? It could be useful for the whole community.
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#8
Basically a listening environment (mixing studio, dub stage, auditoria etc.) is calibrated so that it delivers a standardized audio response, in frequency range, sound pressure and time delay (there are other factors I'm sure). The principle behind this is so that a director in a mixing stage knows that what he is hearing during the mix will reflect what is heard in the movie theatre by the audience. This is why directors like Christopher Nolan will go watch their own films in various cinemas during the theatrical run, in order to check that the cinema is up to standard.
Mixing stages are calibrated routinely (multiple times a day if required), theatres less so. THX Certified Theatres required a minimum standard be met to maintain certification. The point of what I am saying is that it is the playback system (the B chain) which is adjusted and calibrated, usually via pink noise (pinking). The size of the listening environment, it's auditory response, the type of amplification, type of speaker and type of screen will all influence the calibration. Productions pay the big bucks for the mixing studios precisely because they can guarantee what they hear during the mix is what the audience will hear in the theatres. For large (theatre) environments, an X-curve is applied during playback in order to compensate for the room acoustics. Different sized theatres will be calibrated differently. The curve is reviewed periodically by SMPTE/THX/etc. as their research continues. Movie studios do not send out different prints of the same film based on the layout/size of the theatre, the B chain takes care of that.
Any difference between a cinema DTS (APT-X100) soundtrack and it's consumer equivalent (coherent acoustics, HD-master) will be down to the Near Field Mixing applied to the home media, plus any 'creative decisions' made by the production after the fact.
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#9
As most everyone here knows, we don't just start handing things out to new members without any participation happening first. At this point, I do not know what to make of this user, and I believe the language barrier might be part of it.

I'm glad discussion is going on but I will say I did not appreciate you making it sound like you expected me to fill personal requests (again, it could be language barrier). My time and resources are worth just as much as anyone elses here and what we do helps the community, I won't do private requests, ever. I sent you the Spider Man Wav64 files and the cinema DTS in their original .aud form for experimentation.

I'm not trying to be a jerk, I just wanted to be transparent about this, because I like this being a safe place for all like-minded people with the same intentions as ours.
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#10
(2017-07-06, 12:46 AM)Jetrell Fo Wrote: As most everyone here knows, we don't just start handing things out to new members without any participation happening first. At this point, I do not know what to make of this, and I believe the language barrier might be part of it. I'm glad discussion is going on but I will say I did not appreciate Tomlinson maybe expecting I was just going to full his personal requests (again, it could be language barrier). My time and resources are worth just as much as anyone elses here and what we do helps the community, I won't do private requests, ever. I sent him the Spider Man Wav64 files and the cinema DTS in their original .aud form for experimentation.

I'm not trying to be a jerk, I just wanted to be transparent about this, because I like this being a safe place for all like-minded people with the same intentions as ours.

Hello!

I am very disapointed, that you drag something which was discussed privat into this public part of the board.
Leaving 90 % of the hole story away makes me appear in a very bad way, like I just want something from here and not willing to give anything back.
Those who have been involved how I came here and you will know the true story.
In addition your text does not have to do anything with the discussion here of the x curve.
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