AUDIOPRESSBOX CONFERENCE SPLITTERS
Press splitters are used to avoid the unsightly clutter that results at events such as press conferences, when every broadcasting organisation present tries to erect a microphone directly in front of the speaker, precisely where the cameramen would rather they did not. The splitter takes a small number of inputs from microphones or the local mixer and distributes the signal to a large number of outputs for use by the media. Audiopressbox offer a comprehensive range of active and passive types in stage box, floor-box, desktop, rack and wall mounting formats as well as portable, cased, splitters and kits.
For a very limited number of broadcasters and journalists it may be possible to provide a set of outputs using multiple microphone splitters. However, this technique quickly increases the load on a microphone to the point where the signal quality is affected. A dedicated conference splitter will reduce clutter, be more reliable and prevent inter-action between the connections made by the different members of the media. Alternative terms for press splitter include 'conference splitter', 'presidential bridge', 'press box', 'multi box' and 'press distribution amplifier'.
Typically, passive types have an input (or inputs) which is designed to be fed by the balanced, analogue, line-level output of a mixer or pre-amplifier. They consist of a number of balancing transformers each with circuitry which reduces the effect on the input signal if one of the outputs is short-circuited or connected to ground. The number of output channels which may be connected to the mixer output is set by the output impedance of the mixer, and is not, typically, large. The circuitry also reduces the outputs to microphone level which will suit many cameras and recorders. Since they require no power, they are reliable and simple to use.
Audiopressbox offer both press splitters and 'expander' units, which use this technique. Some can be driven by a line-level output, but some are intended for use with dedicated 'drive units'.
Built in a steel box, designed to be placed on the floor, this has a 3-pin female XLR for the audio input on the side and a male link-out XLR. Two handles on the upper surface provide a degree of protection for the twelve, 3-pin male XLR outputs, but are also handy for transportation. It is intended to be fed by a professional balanced line output. Twelve independent transformers provide the outputs at -38 dB microphone level for a 0dB input.
Active Splitters and Drive units
These usually have microphone or line-level input(s), followed by an amplifier which then drives numbers of transformer-isolated outputs. They can generally provide many more outputs than passive types and, having onboard electronics, often include adjustable gain, metering, microphone/line output level selection, high-pass filters to reduce low-end rumble and compressors and limiters to control levels and prevent overloads. Since they rely on power to work at all, onboard batteries or redundant power supplies are positive benefits. Listed here are both active splitters and 'Drive units'. Both have similar input features. The splitters have individual outputs and sometimes outputs to feed 'expanders'. The drive units have no individual outputs, and are meant to drive one or several Expanders.
Explanation of the terminology used in the features tables:
Microphone input: Female, 3-pin, XLR input.
Microphone/line inputs: Female, 3-pin, XLR input, with adjacent microphone/line level switching.
Phantom power, 48V: Switch and indicator.
Channel level meter: LED bargraph.
High pass filter: Switch to enable 160Hz high-pass filter.
Compressor/limiter: Switch and bargraph to show gain-reduction.
PFL: Buttons to allow the user to listen to the channel signal using the headphones.
AFL: Buttons to allow the user to listen to the output signal using the headphones.
Headphones: 6.35mm stereo jack socket with associated rotary volume control.
Oscillator: Constant level test signal oscillator with 'no mistake' switch operation.
Output level meter: LED bargraph.
Battery facilities: Internal re-chargeable battery, indicators to show the state of charge, 'battery' and 'power' LEDs'.
The APB-116P has two sloping panels to the front and rear. The two ends are timber, with slots to provide carrying handles. On the rear there are sixteen XLR outputs with adjacent microphone-line level switches. Controls, input and power input are on the front.
Built in steel boxes, designed to be placed on the floor, these have connections for the inputs and controls, metering, indicators and power supply inputs on the side. On the upper surface there are a number of XLR outputs with adjacent microphone-line level switches where applicable.
These are 2U high, rack mounting cases. Inputs, controls and individual XLR outputs are on the front. The rear has the power supply connection, expander outputs and, depending on model, a second power inlet and/or parallel connections to the input connectors on the front panel.
Note (1): Screwdriver operated.
Portable Splitters - Cased
These are built into heavy-duty, waterproof, moulded resin cases, intended for both indoor and outdoor applications. They have internal rechargeable batteries which can power the splitters for ten hours at full load, or can be used as standby power when using the external power-supply and charger.
All controls and connectors are fitted to a flat control panel screwed into the case. There is space at the rear for storing the (supplied) power supply.
Rack-mounting Drive Units - 2U types
Inputs and controls are on the front, there are no individual XLR outputs. The rear has the power supply connection, expander outputs and, depending on model, a second power inlet and/or parallel connections to the input connectors on the front panel.
Rack-mounting Drive Units - 1U types
Controls are on the front, connections are on the rear.
These contain independent transformers and provide individual 3-pin female XLR outputs. They are passive devices, having balanced inputs to be supplied from either a professional balanced line output or Expander outputs of Audiopressbox splitters or drive units. The balanced output from most devices, such as mixing consoles, is not powerful enough to drive a large number of outputs, hence the drive units are offered to build large systems.
The stagebox types are built in steel boxes, designed to be placed on the floor. On the upper surface there are a number of XLR outputs with adjacent microphone-line level switches where applicable. Two XLR connectors provide input and loop out.
These are supplied with a flush-mounting box, dimensions 153x98x70mm, to fit into the wall. Individual XLR outputs, with mic/line switches where included, are on the outer plate. Two 3-pin Phoenix style connectors on the side provide either input and input-link or inputs A and B.
On-wall types are built in a surface-fixing, metal box. Individual XLR outputs, with mic/line switches where included, are on the outer plate. Two 3-pin Phoenix style connectors provide either input and input-link or inputs A and B.
The floor-box type is a metal tray, designed to be let into the floor. Individual XLR outputs with mic/line switches are on a sloping panel. Two 3-pin Phoenix style connectors provide inputs A and B.
The APB-024 R-EX is a 2U high, rack mounting case with individual XLR outputs and mic/line switches on the front. The rear has two pairs of XLR connectors providing input and loop-out for A and B inputs.
[Note (1): These models may driven by a mixer with low output impedance. (2):These models must be fed by a drive unit, since a mixer is unlikely to have sufficient output.]
Press Splitter Kit - Drive unit and expanders - APB-1.32 CB
This includes an APB-D100 drive unit with a single line input and four APB-008 SB-EX portable expanders to provide 32 mic/line outputs. These are supplied in a fitted, heavy-duty, waterproof, moulded resin case.
Each output is independent, transformer-balanced and isolated. The drive unit has 2 buffered expander outputs and can power up to 48 mic/line outputs. Any Audiopressbox expanders can be connected to the drive unit, not just the ones in the kit.
An advantage of this combination of units is that the portable expanders can be connected in a chain in two directions. The total length of the cable in each direction can be as far as 500m, so any conference room of any type or shape can be covered.
The RC 3.5 -1 cable is intended for use between the mic or mic/line outputs of the splitters and expander units and recording equipment with 3.5mm jack inputs, microphone or line level, regardless of the stereo or mono configuration. The 3-pin female XLR contains electronic circuitry to provide level and impedance matching and DC blocking. The cable is 1.5m long.
The RC 3.5 - 8 is an eight-way cable which provides eight channels of the same functionality and is 3 metres long. It consists of an eight pair multipair cable, broken out into eight tails at each end.