49 Applications for Government and Military
10 Items Per Page
Loudspeaker or Headphone Listening Station for Microphones Positioned in An Observation Room
AN-2218
Description
Two microphones positioned in the observation room are preamplified and mixed by the ST‑MX2 audio mixer. The line‑level output of the mixer is amplified by the D‑HPA3 3.5 watt power amplifier to feed a wall‑mounted loudspeaker. The D‑HPA3 includes a separate headphone amplifier. The speaker amplifier is set (rear‑panel switch) to mute the speakers when headphones are connected. The front‑panel volume knob controls both the power amplifier and the headphone amplifier level. The high‑impedance bridging input on the D‑HPA3 allows the audio output of the mixer to also feed a recording device.
RFI Suppressed on Six Signal Conductors
AN-2177
Description
The ST‑FS6 Ferrite Suppressor / RF Filter is used to attenuate excessive RF interference (RFI) induced in the wiring conductors by a nearby communications tower. The passive ST‑FS6 provides six isolated channels of highly effective ferrite RF suppression without capacitance to ground or series resistance. Two ground terminals are provided to be used as tie points for connecting cable shields (not pictured). The ground lugs have no internal connection to the suppression circuitry. Each of the six I/O terminals may be used independently for the suppression of RF on Audio, dc power or logic control signal conductors. RF interference on audio and control wiring causes unwanted audio noise or instability in control circuits. The ST‑FS6 is normally installed at the rack where signals are received. It is possible that interference may interfere with audio or control sending equipment, making it beneficial to install a suppressor module at both ends of the long interconnection lines.
Multiple Control Points Provided by Rotary Optical Encoder Remote Controls with Muting
AN-2169
Description
This basic sound system provides two D‑RLC10M Remote Level Controls with Muting for end users to adjust the volume from two different locations. The master D‑RLC10M creates the 0 to 10 Vdc control voltage that sets the gain of the ST‑VCA3 Voltage Controlled Amplifier. The ST‑VCA3 adjusts the audio level feeding the system audio power amplifier. The slave D‑RLC10M sends up/down and muting commands to the master D‑RLC10M. An end user can turn the volume up or down, and mute or unmute the system from either remote control. Pressing the MUTE button on either D‑RLC10M shuts off the audio signal. Audio is restored to the previously‑set level when the MUTE function is released by pressing either MUTE button again. These controls, one set to MASTER and the other to SLAVE, are shown connected to an ST‑VCA3 Voltage Controlled Amplifier but can be used with any other RDL VCA or OEM product requiring a 0 to 10 Vdc ramp for level control. As many as ten D‑RLC10M Remote Controls may be connected together in one zone. These remote controls are also available in black (DB‑RLC10M) and stainless steel (DS‑RLC10M).
Courtroom Judge Selects from Three Sources to Feed Active Loudspeaker
AN-2230
Description
The D SERIES‑PSP1 Decora‑Style Active Loudspeaker is ideal for use as a near field monitor in courtrooms, legislative chambers and conference facilities. In this courtroom the three main microphones, Prosecution, Defense and Witness, feed the courtroom’s audio system. Each mic source is preamplified to line level and fed into a TX‑TPS3A Format‑A three‑pair sender which sends the three signals to the judge’s bench over UTP cable. A D‑TPRX3A three‑pair selector receives the audio; the judge selects the desired source via the front‑panel pushbuttons. The D‑TPRX3A selector is mounted in a DC‑2W two gang Decora desktop chassis along with a D‑PSP1 active loudspeaker equipped with a front‑panel level control.
Remote Controlled Mixer Provides User Adjustment in Multi-Purpose Space
AN-2085
Description
The RDL FP‑TPX3A Remote Controlled Mixer makes setup easy for a wide variety of uses in this hotel meeting space. A visit to the AV closet is not required when shifting from one use to the next. The three FP‑TPX3A inputs are fed from any of the Format‑A twisted pair senders. Each Format‑A input module provides one balanced microphone input. (Line‑level Format‑A input modules are also available.) The three input modules are chained together and connected to the mixer using standard twisted pair cable with RJ45 connectors. A separate twisted pair cable connects the D‑RC3M Remote Mixing Control to the mixer. The D‑RC3M provides a separate level control and mute button for each of the three inputs. The wall mounted control is simple to use and easy to understand even for facility users with no technical background. The FP‑TPX3A provides a solution for flexible use of multi‑purpose rooms that does not require technically trained staff for setup.
Real-Time Metering Confirms Loudspeaker Circuit Continuity
AN-2168
Description
The RU‑SM16A Dual Audio Meter is installed to provide a visual indication of the amplifier output level as well as a verification of the speaker circuit’s continuity. One meter string is driven directly by the amplifier output while the second is fed by a return cable connected to the last speaker in the circuit. During proper system operation, both meter displays are identical. Any fault in the system causes the level to drop on the meter connected to the end of the constant voltage speaker circuit. The RU‑SM16A Dual Audio Meter and RU‑SM16D Quad Audio Meter provide precision audio level metering of line‑level audio as well as constant voltage or low‑impedance loudspeaker circuits.
Balanced Audio Connections Between Stereo Unbalanced Devices
AN-2095
Description
Unbalanced audio is not suited to long distance transmission due to susceptibility to hum and ground loops. This problem is avoided by balancing the audio source prior to transmission and by isolating the received signals with effective common mode (hum) rejection. This application uses an RDL STA‑2A Dual Line Amplifier to boost the unbalanced stereo source up to the standard +4 dBu level to drive a pair of balanced lines. The balanced lines may be shielded or unshielded (UTP) and may be up to several hundred feet long. An RDL TX‑A2D Dual Audio Converter receives the balanced audio, converts it to unbalanced and attenuates it to a standard ‑10 dBV level feeding RCA output jacks. Studio quality audio transformers in the TX‑A2D provide very high common‑mode hum rejection and galvanic isolation from the balanced lines. The received remote source is connected to one of the stereo unbalanced inputs of an RDL EZ‑MX4L stereo audio mixer that feeds the conference room amplifiers and speakers.
Mixing a Microphone and Stereo Source to a Single Line
AN-2198
Description
The sound system in this room is equipped with a mono balanced input from the floor box. When the podium is in use, the presenter uses the microphone and also uses an audio player or laptop computer. The ST‑UMX3 Universal Audio Mixer is installed to mix signals from a single dynamic microphone and the unbalanced stereo source located in the podium to a balanced mono mic‑level or line‑level (switch‑selectable) feed to the sound system input. The small size of the ST‑UMX3 allows it to be installed in the podium or the floor box. The ST‑UMX3 3X1 Universal Audio Mixer is used to combine signals of different level, impedance or balanced/unbalanced configuration. Each input and the output is switch‑selectable for mic or line level. Single‑turn trimmers are provided for the gain adjustment of each input.
Loudspeaker or Headphone Listening Station for Microphones Positioned in An Observation Room
AN-2223
Description
Two microphones positioned in the observation room are preamplified and mixed by the ST‑MX2 audio mixer. The line‑level output of the mixer is amplified by the D‑HPA3 3.5 watt power amplifier to feed a D‑SP1A Decora‑Style loudspeaker. The D‑HPA3 includes a separate headphone amplifier. The speaker amplifier is set (rear‑panel switch) to mute the speakers when headphones are connected. The front‑panel volume knob controls both the power amplifier and the headphone amplifier level. The high‑impedance bridging input on the D‑HPA3 allows the audio output of the mixer to also feed a recording device.
Two-Zone Noise Masking System for Office Space
AN-2039
Description
This application shows the layout of a two zone noise masking system. The white noise line output from the RDL ST‑NG1 feeds the inputs of two RDL FP‑PEQ3 parametric equalizers. The FP‑PEQ3 equalizers allow the installer to flatten the noise spectrum in each zone. The line output of each FP‑PEQ3 is fed through RDL FP‑PA20A 20W, 70/100 V power amplifiers. The 70 V output of each FP‑PA20A feeds multiple 70 V speakers in its associated zone. Multiple equalizers and amplifiers may be added for larger systems with more zones.