StageBug™ SB5W Development

With the proliferation of digital audio sources in the form of computers, laptops and iPhones, a need has arisen for an interface that anyone can use when making a presentation in an auditorium, convention center or boardroom. Although this may seem like a simple 'source to PA' connection that could be addressed by a typical direct box, there are often challenges that require an alternate solution.

The first challenge is convenience and esthetics. Often the public address system is mounted at one end of the room - so running long cables across the floor is both unsightly and problematic as they get in the way of foot traffic. The next challenge is making sure the interface is at the ready when needed. Further, anyone who has tried to interface a computer with a video player and PA system has likely experienced noise problems in the form of hum and buzz that tends to find its way into the audio system. This not only distracts the presenter, but makes comprehension more difficult. Finally, with users coming from all walks of life, the interface had to be easy enough to use for anyone while providing sufficient control to make a seasoned professional happy and installation to be contractor friendly. The Radial SB5W was designed from the ground-up to address all of these.

What is a direct box anyway?

A direct box or DI is a clever interface that converts an unbalanced line level signal to a balanced mic line, enabling super long cable distances to be achieved without signal loss. Before the advent of digital, telephone companies employed balanced lines to transmit telephone conversations thousands of kilometers. The SB5W is a stereo direct box that produces a mic level signal at the output to feed the mic input of a mixer.

Wall-mount design

The most effective means of ensuring the DI at the ready is by permanently mounting it inside a wall. This not only ensures it does not get lost, but it also eliminates unsightly wires by running these inside the wall to the far end of the room where the PA system is stationed. This allows a presenter at a podium to have a laptop nearby or maybe allows the club owner to 'pipe' the stereo in the bar to the PA system when the DJ or band is taking a break.

Contractor friendly features

The SB5W fits inside a standard single gang electrical box and is covered using a standard Decora wall plate. This means that you can go to any hardware store to pick up a single gang box. The balanced connections from the SB5W to the PA system are made using simple screw-down terminals that will accept any size from 18 AWG to 26 AWG (American Wire Gauge) twisted pair wire. Pre-cut slots in the printed circuit board phenolic material let you tie down the wires with the supplied tie-wraps to secure the wire in place before final mounting. A fully enclosed steel back-box means that you can use a plastic single gang box without having to worry about electro-magnetic interference. Since the SB5W is completely passive, no local powering is needed. This eliminates a costly electrical power installation.

Simple user interface

The front panel is designed to be plug & play easy to use with standard stereo RCA and 3.5mm inputs plus a volume control that anyone can use. Should the channel count on the PA system be limited or the audio source be recorded in mono, depressing the MONO switch sums the stereo channel to mono, while feeding the mixed channels to both outputs. As the SB5W is passive, no power turn-on or off is needed. This 'green' design only works when plugged in and the user does not have to worry about power-on transients or electrical consumption.

Eliminating noise

In order to eliminate noise, the SB5W's internal engine is actually a pair of select audio transformers in an RC network to help eliminate radio frequency interference. Transformers naturally block stray DC voltages which are the primary cause of so-called ground loops. A set & forget ground lift switch may further be activated to disconnect the audio ground between the source and the PA system. By incorporating a full enclosure, this not only protects the internal electronics from damage during installation, this also helps reduce electro-magnetic interference from outside devices such as electronic ballasts, lighting dimmers, power transformers and high-power cables.

Delivering great Radial sound

As the market leader in direct box technology, the Radial SB5W follows the same pedigree with a ruler flat response from 20Hz to 20kHz and less than 0.1% distortion at all frequencies. This makes the SB5W perfectly well suited for all types of program material from music to voice.