Film-Tech Forum ARCHIVE: Cinema Sound Equalization

This is topic Cinema Sound Equalization in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Syed Hussain (Member # 10311) on 01-03-2018, 02:05 AM:

Hi,

I am a home theatre developer who is moving into realm of cinema development. I have a couple of questions if someone can help me.

Are the dolby and datasat the only sound processors that are DCP compliant. Also in commercial cinema's how is sound equalization performed?

Thanks

Posted by Marcel Birgelen (Member # 6801) on 01-03-2018, 02:46 AM:

When it comes to audio processors there isn't really a thing like "DCP compliant".

If you want to be DCP compliant, you need to at least support 5.1 audio or better 7.1 audio. The outputs on your server will be generic AES/EBU per channel, which is supported by tons of gear out there. The way you convert those signals from digital to analog and how you distribute and amplify those over your theater are not within the scope, hence there are many solutions.

There are cinema solutions provided by other vendors, like QSC, Trinnov and Barco.

If you want to support Dolby Atmos, then you're obviously stuck with Dolby for the moment, as they are the only supplier of Atmos compliant decoders for DCPs.

Posted by Harold Hallikainen (Member # 5405) on 01-03-2018, 04:40 PM:

The current standard for equalization is SMPTE ST 202:2010 available at http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7291917 . The recommended practice for performing equalization is RP 2096-1:2017 available at http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8023924 (this is the baseline calibration, which is most thorough). You may also be interested in the report "B-Chain Frequency and Temporal Response Analysis of Theatres and Dubbing Stages" available at http://survey.constantcontact.com/survey/a07e9y6vd10i0zj9i4f/start .

Harold

Posted by Syed Hussain (Member # 10311) on 01-03-2018, 11:59 PM:

Thankyou this is really helpful.

The way we do equalization in home theatre is let audssey xt 32 do its thing or we can employ dirac and then change the setting manually in sound processor.

How the process shall be performed in the cinema. Sorry for dumb question.

Posted by Carsten Kurz (Member # 5396) on 01-04-2018, 06:16 PM:

Typically, you do it manually by utilizing a built-in or external spectrum analyzer. Cinema audio systems are usually found in a larger variety and you need to learn how to configure the different types of processors, amps, crossovers and speaker systems in order to configure and use them. I suggest you look up some installation manuals in the film-tech warehouse file archive and make yourself familiar with typical procedures.

- Carsten

Posted by Syed Hussain (Member # 10311) on 01-05-2018, 12:21 AM:

Thanks this is great help.

From my research what I have found out is that only BARCO, NEC and Christie make DCP compliant Projectors. Is this correct or are there more companies?

The sound processors for 5.1 are built by Trinnov, Data Sat and Dolby. Is this correct or are there more companies?

Furthermore, I am looking for companies which have good market reputation for equipment in the following categories Speakers, Media Servers, Amplifiers and 3d Systems.

Posted by Carsten Kurz (Member # 5396) on 01-05-2018, 09:50 AM:

Projector makers are the three DLP TI OEM: Christie, Barco, NEC. Occasionally you may come across Kinoton or Cinemeccanica, but they use(d) Barco main components. The only Non-DLP manufacturer is Sony, which also exclusively bundles their own servers with their own projectors.

Server ('players') are manufactured by Doremi/Dolby, GDC, Sony, Christie, Barco,USL, Qube. A couple of other companies play(ed) in the server market with little impact and you may occasionally find one of those usually outdated systems on a shelf or still playing in underfinanced locations (XDC, QuVIS, Datasat/Qube, Kodak).

Only projectors and servers/media blocks are actually tested for DCI compliance. Audio processors are not.

See here: http://www.dcimovies.com/compliant_equipment/

As audio processors are not tested for compliance, the market is a bit broader. In fact you could setup a cinema without any of these dedicated products, using certain home cinema or general use PA components. Not advising to do it, though.

Dolby, Datasat, dts, QSC, USL (now QSC), Trinnov, some Barco, GDC OEM, etc are typically found on sites. I noticed some cinema processors being manufactured in/for far east that never turn up elsewhere in the world.

- Carsten

Posted by Steve Guttag (Member # 268) on 01-05-2018, 01:00 PM:

Slight correction to Carsten (very slight). The Dolby CP850, because it "touches" the raw data to decode Atmos, is also DCI compliant and is part of the TDL (Trusted Device List). It only matters when running Atmos DCPs though.

Posted by Carsten Kurz (Member # 5396) on 01-05-2018, 03:14 PM:

Before I finished my post, I actually tried to find the CP850 on the DCI equipment list and couldn't find it. Maybe there is no formal CTP yet for audio processors? Yes, every equipment incorporating an SPB should be compliance tested.

Another reason for the missing CP850 compliance doc may be that object based sound systems until now are proprietary and are neither standardized on DCI nor SMPTE level.

- Carsten

Posted by Ken Lackner (Member # 1002) on 01-05-2018, 03:46 PM:

Sidebar: What does SPB stand for? I often see this on Doremi servers and could never figure it out.

Posted by Steve Guttag (Member # 268) on 01-05-2018, 05:39 PM:

SPB = Secure Processing Block

Posted by Syed Hussain (Member # 10311) on 01-06-2018, 08:31 AM:

Hi,

Thankyou this absolutely amazing information. Thankyou very much.

Can somebody also suggest 3d systems Manufacturers and Speaker Manufacturers.

Thankyou very much once again.

Posted by Marcel Birgelen (Member # 6801) on 01-06-2018, 09:39 AM:

What the best 3D solution is, will differ from customer to customer, so you probably want to offer some alternatives.

Probably the best system on the market right now, when implemented correctly, is Dolby 3D. It also is generally the most expensive one to do right.

RealD is usually one of the cheaper options looking only at the installation costs, but the exhibitor has to pay a licensing fee per 3D show. Also, the screen needs to be either a silver screen or a white screen with special coating.

There are several other suppliers of 3D systems, most notably XpanD, which offers both a polarized 3D solution and an active shutter-glass solution.

Keep in mind that the general interest in 3D in most markets seems to be fading though.

As for speakers, there are many manufacturers that supply speakers targeted at the cinema market. The most common brands right now are probably QSC and JBL Professional.

There are no real one-size-fits-all speakers, so the type of speakers you need for a certain job will differ.

Keep in mind you also need amplifiers. Common suppliers for professional amplifiers are for example QSC and Crown Audio.

Before you start a business in this, it would be wise to see if you can hire someone with a background in this industry. It can help you enormously in getting a head-start.

Your customers are also going to demand a certain quality and usually don't really like to be the guinea pig, until their supplier figured out how it all works.

Posted by Syed Hussain (Member # 10311) on 01-12-2018, 12:48 AM:

Hi,

Thankyou everyone for your help.

Can somebody please confirm if I would require Screen Masking for commercial theater and if yes which companies are recommended providers of screen masking technology.

Posted by Marcel Birgelen (Member # 6801) on 01-12-2018, 02:37 AM:

Most screen masking systems are installed by local installers. Unfortunately, I don't really know which ones are active in your specific region.

Although screen masking is nowadays disappearing from many commercial movie theaters, it should actually still be a part of any self-respecting movie theater.

Proper masking will make the difference between something looking like a glorified business presentation or big-size TV and a real moviegoing experience.

It will also greatly increase the perceived contrast of the image and it will also increase the immersion into the movie. The screen will be much more like a window into the world of the movie. The ugly black bars are an obvious artifact of improper framing or masking and destroy a part of this illusion.

Posted by Carsten Kurz (Member # 5396) on 01-12-2018, 05:46 AM:

Let's stress there is a difference between screen masking and variable/moveable screen masking. I still hope every cinema does at least have screen masking ;-)

- Carsten

Posted by Marcel Birgelen (Member # 6801) on 01-12-2018, 07:43 AM:

Unfortunately, a lot of cinemas don't even do proper "static" screen masking anymore. They essentially don't even do much to hide stuff like trusses the screen is mounted on...

Also, there is a new trend: The floating screen. Usually, the screen floats in front of a black or every dark background though. I think a floating screen is still better than a totally unmasked screen.

Some of those floating screens use LED strips around the edges, to create a halo-like effect around the screen during the pre-show.

Posted by Syed Hussain (Member # 10311) on 02-05-2018, 01:57 AM:

Can somebody suggest a good brand for screen and motorized screen masking.

Also as all movies have the same aspect ratio, so do i really need a screen masking system.

Thanks

Posted by Carsten Kurz (Member # 5396) on 02-05-2018, 08:37 AM:

quote: Syed Hussain
Also as all movies have the same aspect ratio

You are a lucky man.

- Carsten