Digital Test Tools

Ceiling Installation

Details
Category: User's guide
Last Updated: 23 May 2014
Written by editor

The DXG is built to be suspended from a ceiling, as well as used on a tripod. The center brass insert is used for either purpose. In addition, there are 4 holes that take a 2 inch, 1/4-20 Eye Bolt and nuts, which are then use braided wire for safety. 

DXG hanging and tripod mounts

The eye bolt is screwed into the through-case holes, then locked down with a pair of nuts for added safety. If there are laws or specifications or recommended practices that say otherwise, please follow appropriately. These are merely our suggestions.

The bolt should be the type that has a completed circle, not a hook, on the opposite side. A cable can be tied to or run through the bolt and then correctly hung from the ceiling.

 

 

 

 

 

Attach safety nut

Installing one of 4 bolts

 

 

 

 

 

 

 

 

 

The DXG weights between 1 kilo and 1.5 kilo depending on the options installed. There is a cable tie to dress the cables attached to the box. [Typically this will be one CAT-6 cable and one cable for the D9 connector.]

Safety concerns dictate that all 4 hooks are used with separate pieces of cable. The cable should be connected in a similar manner as a drop ceiling, and not be laid over struts that will rub and cut the cables.

The smaller colorimeter is small and light enough that it might not need more than the physical connection of one 1/4-20 device holding it in position, with its locked RSS-422 cable also giving support.  

The DXG is powered by a technology called Power over Ethernet (also known as PoE, with the small 'o'.) Briefly, this internationally standardized technology allows power and Ethernet signals to co-exist on a CAT-5 or CAT-6 cable, then into the RJ-45 connector of the equipment. The power is then separated and used as if they had come over separate cables. Depending on the cable that you use, there is a limit of 100 meter cable length. CAT-6 cable is preferred over CAT-5, and may be required for longer distance runs.

The mixing of data and power is done at one of two places. Either there is a separate PoE Insertion Device, or there is an Ethernet Switch that is PoE capable. Often these switches will only power 4 of the available ports – watch out for that. Either technique works well (especially if the insertion device and its power and CAT-5 cables are securely mounted). Either technique adds yet another potential point of failure to your system, but the Ethernet Switch is perhaps the better long term solution since a switch is needed for other purposes in that location.

In addition to the RJ-45 connector, there is a connector called a DB-9 on the rear of the DXG which is used to carry power to the colorimeter sensor, and carry the colorimeter signals back to the DXG processor located in the saucer section. This cable doesn't need to be connected in order to set up a DXG with a network – i.e., several DXG units can be configured simultaneously at the tech bench without sensors attached. 

NB: When purchasing a cable with DB-9 connectors at each end (one male, one female – often called an RS-422 or RS-232 or RS-485 cable), make certain that all 9 pins are carried through with cable between them. There are some uses of this style of cable that allow manufacturers to only implement 4 or 5 connectors. These will not work.

Since these cables will be used to carry power – albeit low voltage power – please consult a local Code expert about whether you situation requires "plenum rated" cable. (See: Cable-Selection-for-RS422-and-RS485-Systems)

An easy alternative to buying a pre-made  RS-232 style cable is to purchase a reel of flat 'ribbon' cable and the male and female connectors for it. Flatwire can be bought with twisted cables for noise immunity. As you can see from this linked YouTube 'how to', adding connectors is a simple process: Flat ribbon cable assembly - YouTube

 

Where to install the two parts to the Digital eXperience Guardian System.

DXG wiring from above

The larger part is the 43 x 3 cm, nearly circular case – some call it the saucer section. Around the edge you will notice the holes for 4 microphones and in the slightly raised dome is the 5th microphone capsule, which should be pointing downwards. It should be hung from the ceiling just above the light (to get it into the soundfield as much as possible.)

The 2nd part is a box with a colorimeter in it. There might be several of these per system, but at least one is required. It connects with that DB-9/RS-485 connector that you learned of earlier. If there are multiple colorimeters, they are daisy-chained together.

They should be pointing at the screen from a distance of 2 or 3 meters, depending on the size of your screen. It can point to the center from the side or from above (or even from below if there is a secure place to mount it.) 

Generally speaking, this is how they fit into a room.

Generally speaking...the setup

 

 

The flattened rear section of the Gaurdian is the connector bay which, left to right, has USB, DB-9 and RJ-45 (Ethernet) connectors. A USB cable will plug into a portable computer, which can supply the DXG with power, and with the supplied software operate the system. The RJ-45 connector also supplies the system with power using a power over ethernet insert, and allows the system to be run remotely with local or remote database and VPN connections. (IF BOTH USB and Ethernet cables are connect, the system selects the network system power and control.)

The DB-9 connector routes RS-485 protocols and power to one or more remote colorimeter units. These are placed near the screen according to your room situation. Details of this connection are supplied with the unit and in the tech materials on this site.

Finally, many systems will be fitted with a secure camera system in the front 'nose' of the audio section. This serves as an analyzer for the forensic marking systems, and as a low-quality CCTV substitute which can feed a picture to your NOC or corporate headquarters. There is separate AES-256 encrypted password protection on this camera, and the picture quality is quite crippled on purpose.

The DXG should be pointed slightly down toward the center of the screen. If there is a camera in the nose of the DXG it should be focused when it is in position.

Position of the DXG Audio and Colorimeter Cases

The larger, audio portion of the system is meant to be placed in the center of the auditoium, about 2/3rds back from the screen toward the rear wall. If the choice is to be somewhere else, stay on the physical center line of the room (not the screen.)

It should be hung so that it is just slightly higher than the light line from the projector.

The colorimeter case should be 1.5 - 3 meters from the screen, mounted above or below, or to the side and pointed toward the center of the screen.

If it seems that these are inexact measurements, it is because it is true. The system is based upon changes in sound and light, relative to a baseline reading. That allows some latitude in the placement. For example, while we might sugest that the colorimeter be 1.5 meters from the screen for your installation, significant data can be gathered as far away as 5 meters. But we should remember that the colorimeter is a 16bit/color, 1,000,000:1 dynamic range device, and the DCinema standard is 12 bits/color and 2,000:1. The point is, don't take too much latitude, but don't be psychotic about exactness at the expense of logic or convenience.

Guardian Hanging with Colorimeter facing the wrong way to show the front

There are certain considerations. The NetSec™ Confirm IP testing system wants to have a fast connection to your IP network. If you have one projector with a 100Gig feed, then this is the system that the NetSec™ Confirm IP testing system should be on.

The same camera is used for the CCTV Replacement system and for the Forensic Validation System. Focus obviously isn't the highest concern for the CCTV system as the management and booth personnel only need to know that something is playing or that the sub-titles are working or being able to tell that the trailers or end credits are playing.

On the other hand, the NetSec™ Confirm is going to send a picture to someone else who would like to have enough quality to make out the forensic marking (also incorrectly called, the watermark). So there is need to have the camera in good focus for that.

If there are any questions, please look in the Forum or write or call.

Home Documentation Ceiling Installation

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