The Balun Revolution

In Uncategorizedby tfwm

Baluns have become a common consideration when installing or retrofitting an audio/video system; and more often than not, contractors familiar with the versatile and cost-effective devices choose them over traditional audio and video wiring methods.

However, in some arenas, baluns have experienced a prolonged reception – staunch supporters of coaxial and twisted pair audio are hesitant to break tradition and place their faith in a small, simple device.

After all, traditional audio and video wiring has an established track record and baluns may seem a recent novelty. It’s hard to believe two small devices and a run of inexpensive Cat 5 could replace almost a century of tradition – the time-honored tradition of installing bulky cabling into beautiful houses of worship. Here I should mention that Cat 5 is a type of UTP, or Unshielded Twisted Pair, cabling. But change is finally in the wind.

Though they have been around for over 50 years, baluns are only now finding a place in houses of worship. New installations benefit from UTP’s low cost and extensive transmission distances, whereas baluns allow installation retrofits to utilize already existing structured cabling systems with the versatility of multiple aesthetic transmission options. But before examining applications in depth, a brief balun overview may prove effective.

Quite simply, a balun is a small transformer which converts an audio or video signal from balanced to unbalanced and vice-versa (hence the word bal – un), essentially making the necessary impedance adjustments for transmission between different wiring systems. If the transformer inside the balun is wound 3:1, it allows a 150 ohms balanced load to be transmitted over a 50 ohms structured cable; if it is wound 4:1, the balun allows a 200 ohms balanced load to be transmitted over a 50 ohms structured cable; etc. The real key to the system is the nature of UTP: all Cat 5 cabling conforms to a specific standard which facilitates the impedance matching design of baluns.

But what does this mean in plain English? This means baluns can send audio, broadband video, baseband video, and VGA over any regular Cat 5 cable that might just already be installed in your church. And if Cat 5 hasn’t been installed, it can be for a fraction what coaxial, VGA, or twisted pair audio would cost.

For example, assume you have been asked to permanently install in the parish hall a television that will occasionally be used to view audio and video from services taking place in the sanctuary. The camera which will feed these televisions is about 1000 feet away. Wiring with coaxial and twisted pair audio will cost approximately $350: coaxial costs about $0.25 per foot (x1000) and twisted pair audio costs about $0.05 per foot (x2000 they want a stereo audio feed). Using baluns and Cat 5, however, will only cost about $230: UTP cabling such as Cat 5 costs about $0.05 per foot (x1000) and audio and video baluns usually cost about $90 (x2 one for each end of the run of cable). Thus, in this scenario, using baluns and UTP will save about $120.

Depending on the balun type and manufacturer, actual price and transmission distances vary. Typically, audio only and video only baluns are least expensive and VGA baluns are most expensive, but different variables such as the number of connections and connector type effect price. Regardless, baluns can accommodate the specifications of almost any audio/video installation.

Some examples; audio baluns are offered with either two or four connectors which distribute up to 2500 feet; broadband and baseband video baluns with one to three connectors which distribute anywhere from 500 to 2000 feet; audio and video baluns with multiple audio and video connectors which distribute up to 2500 feet; and VGA baluns with one to multiple destination connectors which transmit up to 350 feet. Sometimes, however, baluns even accommodate more than just audio, video, and VGA the Intelix V1-PTZ video balun passes camera pan, tilt, and zoom commands. Thus, depending on the balun, transmission distances can be as large as connectivity options are diverse.

At this point you might be thinking, “Who cares about price if the signal is severely degraded; after all, the audio and video signals are being balanced and transmitted over numerous feet.” In a worst case scenario, active baluns with Automatic Gain Control are available; but surprisingly, if the conversion is truly balanced/unbalanced and the recommended maximum distances are not exceeded, there should not be any noticeable signal loss or signal degradation. In fact, because baluns act as isolation transformers, they even maximize audio signals by eliminating the ground loops that cause background hum and rolling interference.

Price, performance, and options – what more could anyone ask for? How about appearance and versatility. Many houses of worship opt for baluns and UTP because they maintain the aesthetic decor of the church while remaining flexible for future adjustments.

Being as bulky as it is, coaxial is difficult to hide – and if it isn’t well hidden, it can seriously decrease the aesthetic appearance of your church. UTP such as Cat 5 eliminates this problem because it is thin – about half the size of coaxial, and is easily pulled and run internally through walls.

Each strand of UTP is also much more versatile than coaxial; a single run of Cat 5 can transmit audio, video, audio and video, or VGA signals. Because baluns simply match impedances, it easy to swap baluns which transmitted audio from a CD player to a receiver yesterday for baluns which will transmit video from a camera to a monitor today. Plus, many baluns are easily placed in remote locations because they are passive and do not require any electrical power to operate.

This is not to say all baluns are passive. Whereas companies such as Intelix, ETS, and Blackbox primarily sell passive baluns for basic audio and video distribution, Extron, Altinex, and Kramer sell active baluns requiring a dedicated power supply. Since they are powered, active baluns can typically transmit audio and video signals much further than baluns of the passive variety (most active baluns transmit up to 5000 feet, or 1 1/2 kilometers) because a dedicated power supply facilitates such features as built-in Automatic Gain Control which corrects any loss in picture brightness, sharpness, and contrast. However, most houses of worship rarely need to transmit audio and video over 1 1/2 kilometers.

Typically, houses of worship rely on baluns for simple audio and video distribution audio from the pulpit to the crying room, video from the church to the parish hall, VGA from a computer to a projector, and sometimes in CCTV security applications.

Whether retrofitting or installing a new audio/video system, baluns and UTP present an ideal solution – they are truly transforming churches into multimedia masterpieces, inexpensively and aesthetically.