Dwight Weller

The Fibox from Lightwave Systems inc. (LSi) is a creative approach to transporting broadband (0.1 Hz to 25 kHz) two-channel audio on one fiber optic cable.  It can do so with no degradation or compression-related artifacts.

Using 20-bit linear A/D and D/A conversion, this "Cool Stuff"-winning product marks a milestone in hauling audio point-to-point while eliminating problems often associated with distance, copper wire, ground loops and EMI/RFI.

On the panel
The FBAI-M transmitter of the Fibox set measures 5.7 inches by 1.7 inches by 8.2 inches and weighs less than four pounds, making it easy to slip into a remote kit.

The rear pane; of the unit features XLR connectors for audio input, a phase reversal toggle switch, 12 VDC power jack, a DB15F data port and an ST style connector for the multimode-type fiber optic cable.

The front panel contains a mic/line switch and rotary attenuator for mic level control from -70dB to +20.5dB, a 48-volt phantom power switch and a main power switch with green LED power indicator and red overload indicators.

The FBAO-M receiver is of the same dimensions and weight as the FBAI-M and has rear panel connectors for +4dB audio output via male XLR connector and a ground-lift switch along with power, data and fiber ports.

The simple front panel has a power switch, green LED power indicator and a quarter-inch TRS stereo headphone jack.

Hauling audio
The obvious typical applications for the Fibox system include venues where audio must be transported over short or long distances such as STL applications, theme park runs, stadiums, live concerts, film lots and golf tournaments.

The Fibox is capable of wide bandwidth, 100dB channel separation, "A"-weighted 108dB S/N ratio with an IHD+N of 0.006 percent.

SMPTE Time Code may be passed through the master fiber via optional FBSMPTE-I and FBSMPTE-O external modules.  These SMPTE modules replace one Fibox audio input/output pair in multiple channel configurations, allowing five Fibox audio units (10 audio channels) plus SMPTE code on one fiber cable.

Control signals, synchronization protocols or data can be transported through the Fibox with a little coaching from factory technicians.  Conservation of cable can be appreciated in situations where multiple signals and information from the same location are routed to the same destination.

Lighthouse Digital Systems, a seperate company not connected to LSi, manufactures a unit called the Pathfinder which provides additional capabilities when used in conjunction with Fibox.

The Pathfinder is a high-speed switching and routing matrix that accepts virtually any type of digital signal, either in fiber optic cable or as an electrical signal on coaxial cable.

It allows digital-domain switching of the bit-stream from a Fibox input unit (or several units) to various Fibox output boxes, or switching to AES/EBU digital output interface units forthcomming from LSi.

The not-so-obvious uses of the Fibox set include seismic technologies of fault monitoring and oil/gas exploration.  More important to broadcasters: communications links in EMI.RFI-polluted environments that would not otherwise be possible where RPU and wireless mics present unwanted surprises during or before a broadcast.

As an added plus, frequency coordination becomes a thing of the past when optical fiber is used.

In fairness to RW readers, I decided to test it under "real-life" environmental conditions after the bench test and enlisted the aid of supervisory personnel from the local telephone company.  They were helpful in supplying a point-to-point fiber run of greater than two miles with no intermediate equipment that would have weighted our test data.

Because they are in the business of selling fiber optic pipelines to local clients for video and T-1 applications, the local telco was also able to supply test sets capable of measuring exactly what the Fibox system could do.

The tests that we conducted verified that the Fibox performed as well in the field as it did on the bench.  None of the test results changed when the long run fiber was substituted for the short jumper cable.

This fact, when combined with the performance results already proven beyond the published conservatively-rated specs, demonstrates quality almost never found with current technology.

The features supported by the Fibox set - the small size, the 1.2 ampere current requirement at 12 VDC (15 watt AC) and minimal heat production - combine to make the Fibox an excellent addition to a broadcaster's remote system.  In fact, it could probably pay for itself over time, factoring in cost differences between fiber and ISDN circuits as well as connecting non-co-located duopolized properties without tying up their ISDN equipment.

Hop-shots
The Fibox makes those double- and triple-hop STL shots that depend on line-of-site paths, uninterrupted AC supplies of EQ telco lines.  Simple battery packs can provide hours of Fibox use for remote broadcasting or during power failures; telco surge protection is not an issue with fiber systems.

Mobile recording studios, sound reinforcement companies, theme parks and stadiums will appreciate saving money on time, labor and material by using fiber multiplexing instead of expensive multi-pair conventional copper cables and the associated loss of gain and high frequencies over long cable runs.

For information on the Fibox system, contact Lightwave Systems, Inc., in Dallas at (214) 741-5142.