The Yamaha mixer includes a variety of outputs, including two ¼" aux busses: Aux 1 feeds the Telos Xstream ISDN codec, and Aux 2 feeds the regular telephone. The ISDN line is mostly used to provide consistent, clean audio for daily guests of KFLP's agricultural programming who call in from across the United States. The aux bus outputs are critical to the mix/minus capability employed for West Texas Friday Night Scoreboard.
Other Studio A mixer outputs include monitor out to STAV-3870 amplifiers, which power two Realistic Nova-16 speakers for live program monitoring; and a record out that feeds a CPU 2 audio card for recording into the BSI Simian automation system. More importantly, the main XLR and ¼" outputs are reserved for Behringer Multicom Pro XL processors, which represent the only true audio processing within the end-to-end chain.
These feed the CPU 1 audio card for recording to Simian (XLR) and a Barix Instreamer IP audio encoder (¼"). All output feeds are sent through a distribution amplifier to the master control center, the final destination point prior to local broadcast and distribution to the affiliate stations.
The distribution channel
The Barix Instreamer is the first piece of the puzzle in the Internet distribution platform from Floydada to 35 locations. The Instreamer encodes the audio as MPEG-2 stereo with a sample rate of 22.095kHz, which results in a stream rate of 48kb/s, and transports it into a Stream Guys Internet streaming platform for distribution to affiliates.
KFLP purchased a total of 37 Barix Exstreamers, including one spare unit. One Exstreamer sits in master control, pulling the live program off the same streaming architecture as the affiliates and decoding it for local playback over the air. The local Exstreamer interfaces with a Broadcast Tools SS8.2 automation switcher to synchronize the local feed with what is being received at the affiliate stations. The BSI automation breaks into the Exstreamer feed with commercial breaks and promos, provided the show remains on exact time. The Exstreamer also feeds the live signal into a pair of Audiovox monitor speakers for real-time monitoring, allowing staff to act immediately in the event of technical problems with the feed itself or any of the equipment in the chain, such as the ISDN/telephone systems.
The Internet streaming workflow is based on the Stream Guys low-latency Internet distribution service, implemented using Barix's Real-Time Protocol (BRTP) to ensure that program delay at the affiliate side is at an absolute minimum. The aggregated server infrastructure from Stream Guys is comprised of a load-balanced Linux server cluster to receive and transport the feed over a robust streaming network that maintains premium audio quality from point to multipoint. Built-in redundancy at every level ensures the stream is playing out live at all times, with secondary and tertiary streams picking up the live streams in the event the main stream momentarily fails.
KFLP loaded each Exstreamer with Barix's specialist Streaming client firmware and then configured each device with an IP address and port number to capture the stream from the Stream Guys server cluster. Each Exstreamer is configured to check for the stream every five seconds. When KFLP begins pre-roll on Friday, the Exstreamer automatically grabs the audio and is ready for the show at 10 p.m. The Exstreamer continues to check for the stream in the event it is lost during the show, and automatically re-acquires it upon return. The Telos Zephyr ISDN serves as another redundancy layer to the live stream, feeding a toll-free service called Teamline that provides low-latency audio.
At the affiliate site, the preconfigured units are plug-and-play, simply requiring power, network and audio output connections to be fully operational. KFLP affiliates are walked through the initial setup process to ensure proper connections and to confirm the device is enabled to receive the stream without intervention.