Audio Everywhere provides Wi-Fi Audio in sports bars and similar locations so patrons can listen to any TV on their smart phone. We recently examined techniques for the companion challenge of video distribution. In Part 1 we explored five typical configurations. Now, in this follow up, we’ll evaluate the pros and cons of each.
Venue owners must translate the radio frequency TV signals coming into the establishment from a satellite antenna or cable or both, bringing in hundreds of channels per coaxial cable, to multiple TVs, all of which need to be visible to customers.
Centralized vs Distributed Receivers
Separating the various channels from the RF cable requires a collection of receivers. One choice: to distribute receivers near the TVs or centralize them in one location. TVs’ built-in receivers won’t usually decode the copy-protected and encrypted program content that sports bars show, so external TV receivers are the focus.
An additional challenge: HDMI signals do not like to run a long distance.
Generally, TVs outnumber the channels being consumed. A moderately large sports bar might have 8 to 16 receivers and 25 to more than 100 TVs.
Physical distribution architecture
The choice of where to locate the receivers impacts the entire system.
Co-located TV receivers
An option is to locate receivers close to TVs, usually attached to mounting brackets in the back.
Pro: Allows a short receiver to TV HDMI cable to provide the highest resolution image.
Con: Difficult to return audio to a central location.
Pro: Minimizes central points of failure.
Con: Pay for extra receivers to serve every one or two TVs.
Pro: Extra receivers offer low cost/high-resolution solution.
Con: Common control solution is having wait-staff grab remote controls to aim at the receiver behind the TV. Error prone and not a value-added use of their time.
Centrally-located TV receivers
Pro: Control is more uniform, centralized, and even programmable.
Con: Single point of failure.
Pro: This solution can tile four, nine, or 16 TVs into one image for a big game.
Pro: Allows putting any channel on any TV even from different providers, e.g., DirecTV and Comcast.
Con: Harder to distribute high-resolution video because HDMI does not support long distance runs.
Pro: Easy solutions to problems such as “put the game on that TV over there on this TV over here.”
Three signals need to be moved around the facility: video, audio and control.
Type: RF signal from the cable or satellite receiver. Can carry one to many stations.
Description: Basic signaling mechanism used by cable TV and similar systems. Typically runs on 75-Ohm RG6 coaxial cable.
Pro: Inexpensive and widely available.
Con: Needs an end-point receiver with a way to pick the channel.
Type: Composite Video. The yellow wire.
Description: Carries all video information for one cable.
Con: Low quality. Will not do high-resolution.
Type: Component video. Three cables per channel.
Description: Reasonably high quality video; generally highest single-channel analog method.
Pro: Good enough for many sports bars. Lower cost than HDMI and other digital techniques. Runs long distances well.
Con: Cannot do the highest resolution images.
Description: Standard consumer digital high-resolution video distribution standard.
Pro: Highest quality.
Con: Only runs short distances. Splitters and extenders can have issues with copyright protection mechanisms (HDCP).
Description: Format mostly for streaming uncompressed video over CAT6
Pro: Highest quality for long distance. A standard, lowering costs and improving compatibility.
Con: Switching is somewhat expensive.
Type: HDbaseT over IP (emerging competitor is SDVoE)
Description: Combination of HDbaseT and video over IP.
Pro: High quality. Is a standard, lowering costs and improving compatibility.
Con: Very new. Best with 10 Gbit Ethernet.
Type: CAT 5E, CAT 6
Description: Computer networking cable, can run long distances. Used in conjunction with HDMI modulator/demodulator pairs, whether component video, video over IP, HDbaseT, or SDVoE.
Pro: Inexpensive and easy to find people who know how to install. Digital, so no loss of quality due to the wiring.
Con: Conversion devices to and from HDMI can be expensive.
Description: Broadcast quality standard
Pro: Losssless, i.e., no compression
Audio generally streams to two places: (1) the (possibly multi-zone) PA system or (2) a Wi-Fi Audio to smart phones system such as the ones offered by Audio Everywhere. Co-located receivers, (e.g., in a rack in the back) are easy to implement. It is more difficult if receivers are located near TVs. Line level audio signals generally need to be sent back from TVs in balanced mode via a “summing balun,” a device used to transform single-ended analog left and right stereo signals from the (red and white) audio connectors to a single summed balanced signal suitable for running long distances, i.e., more than 10 meters.
Modern TVs often sometimes have no analog audio output ports but rather use TOSLINK optical outputs, which can be simple S/PDIF digital format or more complex, e.g., Dolby. LG-brand TVs won’t even output stereo S/PDIF signals on their optical outputs. Sports bars generally only need mono, and don’t want to pay for expensive converters. S/PDIF (also called PCM) outputs in stereo are available on Samsung and most other TVs, but they still need a device to transform from TOSLINK to electrical analog because the multimode plastic fibers used for TOSLINK are only good for about 10 meters of travel.
Centrally-located receivers allow audio to be grabbed right there, but some centralized receiver systems, such as those in our second example, do not have a local audio output, necessitating bringing the audio back from the TVs anyhow. For example, ZeeVee has this challenge.
Are you confident that a distributed system without a master controller will get the right programs on the right TVs? Or do you want to have a plan and control the chaos?
Below are some of the methods and their pros and cons.
Method: Staff-operated remote controls.
Pro: Inexpensive, equipment-wise.
Con: Not labor-efficient; requires individual line-of-sight interactions and isolating signal from the other receivers. Contortionist skills are useful.
Method: RF remote controls, e.g., those from Home Theater.
Pro: Does not require line of sight.
Con: Intensive setup. How to get the IR signals to the receivers?
Method: RF remotes with IR transmitters on modulators. Applicable when converting from HDMI to CAT 6 and then back. Some modulators/de-modulators have IR receivers built in.
Pro: No line of sight required.
Pro: Converting to IR to control the TV-end receiver is taken care of.
Con: Intensive setup
Method: Brand-specific controllers; Included on matrix switches and receivers such as those from DirecTV.
Pro: Complete solution
Con: Limits one to that brand.
Method: General purpose controllers, such as Control4, Crestron, AMX.
Pro: Programmable, powerful solution for controlling the chaos.
Pro: Tiling TVs into composite images is a great feature.
Con: Expensive to very expensive.
I hope this evaluation of video distribution helps you ask the right questions to achieve the system you want without encountering too many land mines. Good luck.
Thanks to the following for their advice and teachings, Richie Normand of RichieAudio, Rick Marks of Homesmart Central, Jeff Graham of Alaska DTS, and Jeff Mayes of Sportsbar-TV. The insights are theirs and the mistakes are mine.