RB-MM1 Mix-Minus Generator
Whenever programming originates from outside of the studio, or if listeners/viewers are calling up a phone-in using telephone hybrids or codecs, mix-minus feeds are required. Most telephone lines incur delays which prohibit off-air monitoring, because the caller, or remote talent, would hear their own voice in delay which is very disconcerting. The solution is to feed a mix back to the caller minus his or her own voice. Some mixing desks do not have a dedicated telco channel to generate a clean-feed, or mix minus, so the RB-MM1 can be used.
The RB-MM1 is a unit for generating a suitable mix to send to a telephone hybrid or codec. A stereo output is taken from a mixer, together with a post fader output from the mono telephone fader on the mixer. The caller audio is removed from the station output so that it can be sent to the telephone line via the hybrid.
Analogue audio inputs and outputs are via Neutrik XLR connectors. The output level to the TBU can be adjusted using a rear panel pre-set potentiometer. To control the cancellation null (the amount of the telephone channel which is subtracted from the mixer output signal), 2 multi-turn potentiometers are provided, one for the LF null and the other for the full-band null. Additionally, a band pass filter can be switched in and out, via a rear panel switch, to condition the signal for the telephone hybrid. To use the RB-MM1 unit with full-band ISDN codecs, the band pass filter can be switched out. For stereo codecs, or conference calls, multiple RB-MM1 units can be used.
– Contribution and voiceover unit – with talkback
Built in a 1U high, rack-mounting case, the device offers a single microphone channel, routing to a talkback output, two main outputs, for studio and local recorder, say, and the monitor system. The incoming cue and programme inputs are stereo. They could be used, for example, for an off-air feed and remote studio output. The talkback input is mono, and might come from a remote studio talkback system.
The front panel has two large illuminated switches, ‘talk’ and ‘mic’, for routing the signal to the ‘talk’ (‘lazy’) output, for use as a return talkback feed to another studio, and the main outputs respectively. When the ‘talk’ function is active, the microphone signal on the main outputs is muted. The ‘talk’ function is available even if the ‘mic’ function is inactive. Between the two switches is an LED to show when the microphone limiter is in action, and a five stage LED bar-graph. This may be configured to show the level of the microphone signal prior to the switching or only when the signal is connected to the main outputs. Four rotary controls adjust the mix of the microphone, talkback, cue and programme signals to the headphone amplifiers, routed as determined by a matrix controlled by two banks of DIP switches on the underside of the unit. It is possible to route the microphone, talkback, cue left and right, programme left and right signals into neither, either or both earpieces of the headphones. A 6.35 mm jack socket provides the headphone connection, wired in parallel with a similar connector on the rear.
The rear panel has a headphone socket, two male XLR connectors providing the main outputs, each with an adjacent switch to choose either microphone or line level, a male XLR for the ‘lazy’ output, and five female XLR connectors for the mono talkback and stereo cue and programme inputs. The pairs of cue and programme connectors each have a single switch to increase the gain of the signals by 10dB, so that unbalanced sources may be used. The remaining XLR provides the microphone input, and has an associated switch to activate the limiter, while two multi-turn screwdriver operated controls adjust gain and limiter threshold. All XLR connections are balanced. A 9-pin female D-sub connector offers access to the remote control of the ‘mic’ and ‘talk’ functions, and opto-isolated indicator outputs for each. A bank of DIP switches enable the phantom powering, low-cut filter, and extra 20dB microphone gain, as well as the option to mute the microphone signal to the headphones when the ‘talk’ function is activated. A filtered IEC inlet, with adjacent fuse, provides the power connection.
Microphone input: -10dBu maximum, 2kohms. Phantom power: 48V Common mode rejection: Better than 60dB, typically. Microphone gain: +20dB to +80dB, adjustable. Noise: -130dB E.I.N. Distortion: 0.01% THD, 1kHz, +8dBu output. Low frequency filter: 125Hz, 6dB/octave. Other inputs: +26dBu maximum, 20kohms. Limiter threshold: +8dBu to +26dBu, adjustable. Maximum output: +26dBu, less than 50 ohms, for balanced outputs. Headphone output: 150mW into 32-600 ohms. Response: 20Hz-20KHz +/- 0.1dB, 1kHz. Power source: 110V-120V or 220-240V AC, switchable, 9W maximum. Dimensions: 1U rack mounting, 108mm deep. Weight: 1.3kg.
Included accessories: Handbook, AC power cordset with plug.
Optional accessories: RB-RK3 rear panel rack kit.
RB-IPE IP Extender for GPIO & Analogue Control Signals
The RB-IPE is a 1U rackmount unit designed to provide remote control of GPIO and analogue control voltages over an Ethernet network. Configured using a built-in web server, two units can control each other across an Ethernet network, or a single unit can be controlled via Ethernet commands and the web server interface. The unit can be used in any position where you need to remotely acquire GPO signals or remotely control equipment, for example controlling equipment at unmanned posts, outstations or transmitter sites.
Each unit has 16 x general purpose inputs on 8 x RJ45 connectors, consisting of 8 x isolated current sink inputs and 8 x pull to ground protected inputs; and 16 x general purpose outputs on 8 x RJ45 connectors using 8 x isolated relay change-over contacts and 8 x opto-isolated contacts. These rear panel RJ45 connectors have an LED for each GPIO which shows its state.
On another 8 x RJ45 connectors there are also 8 x 0 to 3.3V/5V/12V input signals and 8 output signals nominally at 0 to 3.3V output, with other output voltage configurations possible. The outputs can all be controlled from the inputs of another RB-IPE, or from Ethernet commands.
This allows any tallies and control signals, together with analogue potentiometer movements, to be sent across a network, e.g. for remote alarm points, to trigger failure alarms at a transmitter site and to control remote equipment.
When two units are connected together at different sites, if a general purpose input state changes at one site the unit sends the new state to the other site and the appropriate opto-isolator output changes on that unit. Similarly input voltage controls are monitored and the changing voltage is sent to the remote unit where an output voltage changes accordingly.
The signals can be routed and distributed such that a single input signal to a unit on one site can be routed to multiple outputs in a unit on another site and/or have the logic inverted and distributed to multiple outputs. Also, the state of the GPOs when the unit is powered on can be configured, allowing more reliable recovery of external connected equipment from a power-fail condition.
The analogue I/O control signals can be mapped to give different ranges between the incoming and outgoing signal, e.g. 0V to 5V input giving a 0V to 12V output, or a linear input mapped to a log scale output. Also, by programming threshold values, analogue input voltages can be mapped to GPO pins, e.g. for sending a signal to a GPO when a volume knob is turned too high.
The web server in the RB-IPE can be configured with a static IP address or by using DHCP.
The three front panel green LEDs give an indication of Ethernet connectivity, i.e. they show when commands are being sent/received. The CONNECTED LED shows link status, the GPIO LED illuminates whenever a GPIO state changes and the ANALOGUE LED indicates a change in state of the analogue voltage signals.
The RB-IPE is powered from a universal mains input between 85-264V AC at