Product Applications

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Home > Product Applications > Schools

CLASSROOM SYSTEM WITH SCHOOL-WIDE PAGING
Full-Featured Green Mixer Amp Integrates Paging in the Classroom

AN-2132

Description:
Classroom mic, line and computer audio sources are connected to the HD‑MA35UA Mixer Amplifier through RDL wall plates. A school‑wide paging feed connects directly to the mixer amplifier paging input. The paging source may be either mic or line level. VOX switching eliminates the need for push‑to‑talk contacts. The HD‑MA35UA setup allows flexibility in muting or ducking the other input channels during paging. The only active RDL component is the HD‑MA35UA which powers up when audio is detected. When the system is inactive (no audio in use) it enters the sleep mode, consuming less than one watt for optimum energy conservation. The HD‑MA35UA returns to active mode (turns on) automatically when an audio input becomes present.

CORPORATE CONFERENCE/PRESENTATION CENTER
Laptop Audio, Wireless Mic System, 3 Channel Mixing with 20 Watt Amplifier

AN-2018

Description:
The EZ‑MXA20 provides a microphone preamp, mixer, limiter, tone control, and a stereo power amplifier in a package less than six inches wide. The EZ‑MXA20 handles sound reinforcement whether the audio source is a computer, CD player, live presenter or all three. The power amplifier provides 10 Watts per channel into 8 Ohm speakers or 8 Watts per channel into 4 Ohm speakers. Bass and treble tone controls provide equalization of source material. The limiter controls overloads from clipping the amplifier and an LED on the front panel of the EZ‑MXA20 indicates when the limiter is active.

LONG DISTANCE TWISTED-PAIR VIDEO MONITORING
Camera at Top of Ski Lift Monitored at Ski Lodge Security Office

AN-2114

Description:
The security camera at the top of the ski lift feeds an RDL TX‑TPS1C Active Three Pair Sender. At the end of about one mile of twisted pair cable, a TX‑TPR3C Twisted Pair Receiver feeds the video monitor in the security office. The TX‑TPR3C is set to terminate the twisted pair cable. GAIN and EQ controls are adjusted to compensate for cable losses. Note: Two audio pairs are also available on the RDL Format C modules. No audio is shown in this application; the audio channels could be used to provide talk‑back capability from the upper lift operator station.

COMPACT CLASSROOM SOUND SYSTEM
Integrated Mixer/Amplifier for Classroom

AN-2111

Description:
Audio sources in this classroom connect directly to inputs of the RDL EZ‑MXA20 20 Watt Stereo Mixer/Amplifier. Audio from a laptop and from a wireless mic receiver feed the two stereo line level inputs. This still leaves a phantom‑powered mic input available for occasional use of a lectern or for future expansion. The EZ‑MXA20 provides 10 Watts per channel to the classroom 8 Ohm speakers and allows bass and treble tone control. The EZ‑UCB2 Under Counter Bracket allows mounting below the desktop to conserve desk space while maintaining easy access to controls.

SCHOOL AUDIO/PAGING SYSTEM
School Paging Interrupts Classroom Audio

AN-2058

Description:
This system uses a TX‑PCR1 Paging Controlled Relay to interrupt classroom audio to allow a page to be heard clearly. Classroom audio is fed through a wall plate to the 70 Volt amplifier. The 70 V speaker ouput is routed through normally closed contacts of the paging controlled relay to the clasroom speakers. The paging controlled relay samples the 70 V audio to the classroom paging speaker. Whenever school‑wide paging is active the relay is energized and the classroom audio is interrupted. This allows the page to be heard without interference from the classroom audio. The wall plate used in this example is available in the normal RDL grey/white or in stainless steel with custom labeling available.

CLASSROOM W/ PROJECTOR AUDIO/VIDEO SWITCHING
Computer, Auxiliary Input, Projector w/ variable output, 40 Watt Stereo Audio Amplifier

AN-2046

BASIC CLASSROOM W/ INTEGRATED MIXER AMPLIFIER ON AV CART
Microphone, Laptop Audio, DVD Player, 20 Watt Mixer Amplifier

AN-2015

Description:
The EZ‑MXA20 provides a microphone preamp, mixer, limiter, tone control, and a stereo power amplifier in a package less than six inches wide. The EZ‑MXA20 handles sound reinforcement whether the audio source is a computer, DVD player, live presenter, or all three. The power amplifier provides 10 Watts per channel into 8 Ohm speakers or 8 Watts per channel into 4 Ohm speakers. Bass and treble tone controls provide equalization of source material. The limiter controls overloads from clipping the amplifier and an LED on the front panel of the EZ‑MXA20 indicates when the limiter is active.

PRIORITIZED PAGING
Voice-Over/Paging with Multiple Paging Sources

AN-2010

Description:
In this application several RDL modules are used to create a multiple priority paging system. A local audio source can be overridden by an Emergency Alert System (EAS). Either source is overridden by the School Wide Paging source. The local source from the laptop is fed into a DS‑CIJ3 input plate to provide a balanced mono output to the Music input of an ST‑VP1 Voice‑ Over Paging Module and passes thru the unit under normal operating conditions. The EAS line level audio is fed to the Voice input on the ST‑VP1. A contact closure from the EAS receiver causes the ST‑VP1 to switch from the Music audio input to the Voice audio input. The output of the first ST‑VP1 will feed the Music input of a second ST‑VP1 to allow override by the highest priority source. An RDL STM‑2 mic preamp provides the line level signal to the Voice input of the second ST‑VP1. PTT contacts switch from the Music input to the Voice input to give this microphone the highest priority. The output of the second ST‑VP1 feeds RDLs FP‑PA20A 70 V amplifier and associated 70 V loudspeakers.

BASIC CLASSROOM WITH PROJECTOR
Computer, Projector w/ variable output, 40 Watt Stereo Audio Amplifier

AN-2047

Description:
This classroom is equipped with a computer, projector and overhead speakers. The computer is connected to a jack plate at the front of the room. Audio and video from the audio/video input plate is connected to the projector using standard audio wiring and monitor cable. The projector is used to control the audio level to the speakers. The projector must be equipped with a variable level audio output. Each output channel of the power amplifier powers one 8 Ω speaker. All wall controls and panels are offered in RDL standard white/gray or in stainless steel with custom labeling available.

BASIC CLASSROOM WITH PROJECTOR
Computer, Projector w/ variable output, 40 Watt Stereo Audio Amplifier

AN-2049

CLASSROOM WITH PROJECTOR AUDIO/VIDEO SWITCHING
Computer, Auxiliary Input, Projector w/ variable output, Twisted Pair Audio Wiring, 40 Watt Audio Amplifier

AN-2045

Description:
This classroom is equipped with a computer and with jacks for an auxiliary audio/video source such as a DVD or VCR player. The computer is connected to a jack plate at the front of the room. The auxiliary input is shown at the rear. Audio from each of the audio/video input plates is connected to the projector using twisted‑pair cable. The video is connected using coaxial and monitor cables. Identical jack plates are mounted in the classroom wall and in a box near the projector so the room may be pre‑wired. Installation of the projector is facilitated by plugging its cables into the jacks. The projector is used to switch between sources and to control the audio level to the speakers. The projector must be equipped with a variable level audio output. Each output channel of the power amplifier powers two 8 Ω speakers. All wall controls and panels are offered in RDL standard white/gray or in stainless steel with custom labeling available.

SEND UNBALANCED AUDIO OVER A LONG DISTANCE
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.

CLASSROOM REMOTE CONTROLLED MIXER-AMP
Full-Featured Green Amplifier Saves Energy and Reduces Operating Costs

AN-2130

Description:
The wall‑mounted D‑RC3M allows full remote‑controlled mixing and muting of the audio sources. Computer, DVD/VCR and wireless microphone sources are connected through RDL wall plates permitting energy‑saving passive CAT5/6 and monitor cable interconnection to the amplifier and projector. Video sources are selected by the projector. The HD‑RA35UA drives 70V constant voltage speakers (or 25V if preferred or required by local code) for placement of multiple speakers for optimal audio coverage. The only active RDL component is the HD‑RA35UA Mixer Amplifier which powers up as soon as it detects audio. When the system remains inactive (no audio in use), the HD‑RA35UA enters the sleep mode, consuming less than one watt for optimum energy conservation. The HD‑RA35UA returns to active mode (turns on) automatically when an audio input becomes present.

ELIMINATE AUDIO HUM IN A GROUP PRESENTATION
Galvanic Isolation for Stereo Audio Ground Loop or Computer Digital Noise

AN-2084

Description:
Presentations using a laptop computer face problems of delivering quality audio through an unbalanced connection. Any difference in ground potential between the computer and audio amplifier creates hum that becomes part of the presentation audio. In some systems, digital noise from the computer may also add a constant irritating background noise to the audio. The RDL AV‑HK1 easily solves this common problem. The AV‑HK1 breaks the ground path for hum and ditigal noise using stereo audio isolation transformers in a rugged, tightly shielded enclosure. The AV‑HK1 Hum Killer is a must‑have item for the touring presenter and is equally useful in a fixed AV installation.

BASIC TWO ROOM COMBINING SYSTEM
School Cafetorium Room Combining System with Automatic Audio Leveling Compression

AN-2124

Description:
This cafetorium can be used as one large room or as two smaller rooms formed by movable wall partitions. Each room has one mic and one mono or stereo line‑level input connection through a DS‑J3 input plate. EZ‑MCP1 Microphone Compressors provide consistent level and overload protection on the mic inputs. ST‑CL2 Compressor/Limiters provide the same benefits for the line inputs. The DS‑RCX2 Room Controls provide volume control in each room and allow selection of a common external source (typically background music). The RCX‑5C controls the audio system configuration, separating or combining the inputs and amplified audio to the speakers according to the room usage (one large room or two smaller rooms). The paging input overrides the audio in the entire cafetorium. Note: The RCX‑5C can be used for room combinations from two to five rooms. An HD‑PA35UA Audio Power Amplifier is used for each zone in this system to feed 70 Volt speakers. The HD‑PA35UA has an automatic sleep mode that shuts off the power amplifier when it is not in use. This offers significant energy savings for systems not operated by technical staff.

ELIMINATE AUDIO HUM IN MEETING ROOM OR CLASS ROOM
Galvanic Isolation for Audio Ground Loop

AN-2096

Description:
A laptop computer that is connected to AC power typically produces a ground loop if its audio output is connected to an installed sound system. The difference in ground voltage between the computer and equipment rack amplifier causes a hum in the audio signal. Small ground loop voltages can produce high audio hum levels from the speakers. Installing the RDL EZ‑HK1 between the computer and the system input removes the ground loop using a stereo pair of high quality audio transformers in a shielded metal enclosure. The input jacks are ground‑isolated. A ground‑lift switch allows the output jack shields to be lifted from the metal chassis if required. Audio connections are easy to interface between jack types. The EZ‑HK1 input provides both stereo RCA jacks and a stereo mini‑jack. The output also is provided on stereo RCA jacks or a stereo mini‑jack.

DISTRIBUTED VGA VIDEO TO MULTIPLE MONITORS
Hotel Provides Multiple Video Monitors that Display Daily Schedule of Events

AN-2090

Description:
The daily Calendar of Events listing at this hotel is generated from an office computer. An RDL EZ‑VM14 distributes the VGA signal of the schedule display to three monitors located near the entrances of the hotel meeting rooms. The wide bandwidth of the EZ‑VM14 insures that the same high resolution image seen at the local monitor is seen at each hotel monitor.

CLASSROOM WITH WALL-MOUNTED THREE-INPUT MIXER
Computer, Auxiliary Input, IR Receiver, Projector, Twisted Pair Audio Wiring, 40 Watt Audio Amplifier

AN-2044

Description:
This classroom is equipped with a computer and with jacks for an auxiliary audio/video source such as a DVD player or VCR. The computer is connected to a jack plate at the front of the room. The auxiliary input is shown at the rear. Audio from the audio/video input plates is connected to two inputs of a three input audio mixer located near the projector using twisted‑pair cable. The third mixer input is fed from the line‑level output of an IR receiver. (Note: A paging source could be connected to the third mixer input instead of the IR receiver, if desired.) The video is connected directly to the projector using coaxial and monitor cables. The projector audio output is not used. The mixer controls the level of each audio source using the associated wall mounted mixer remote control. The three knobs on the wall control provide separate audio level adjustment for the computer, auxiliary input and IR receiver. Each output channel of the power amplifier powers two 8 Ω speakers. All wall controls and panels are offered in RDL standard white/gray or in stainless steel with custom labeling available.

AUDIO DISTRIBUTION IN A LANGUAGE LAB
Computer Audio, Instructor Microphone, Multiple Headphone Listening Stations

AN-2019

Description:
In this system, a computer audio signal and a microphone signal are mixed using the RU‑MX4 Pro Audio Mic/Line Mixer. The mixed signal is distributed to multiple headphone listening stations in a language learning lab using an RU‑DA4D Audio Distribution Amplifier. Each listening station features a D‑SH1 stereo headphone amplifier, which includes an integrated level control. Each D‑SH1 is mounted in a DC‑1G desktop chassis. The DC‑1G is constructed from steel and powder coated to provide years of durability in a classroom environment. The design of the D‑SH1 headphone amplifier makes it easy to create systems with an unlimited number of headphone listening stations. Either 1/4" or 1/8" (D‑SH1M) stereo headphone jack options are available. The system design is shown in mono but stereo configurations can be implemented just as easily.

BASIC CLASSROOM WITH INTEGRATED MIXER AMPLIFIER
Microphone, Laptop Audio, DVD Player, 20 Watt Mixer Amplifier

AN-2017

Description:
The EZ‑MXA20 provides a microphone preamp, mixer, limiter, tone control, and a stereo power amplifier in a package less than six inches wide. The EZ‑MXA20 handles sound reinforcement whether the audio source is a computer, DVD player, live presenter, or all three. The power amplifier provides 10 Watts per channel into 8 Ohm speakers or 8 Watts per channel into 4 Ohm speakers. Bass and treble tone controls provide equalization of source material. The limiter controls overloads from clipping the amplifier and an LED on the front panel of the EZ‑MXA20 indicates when the limiter is active.

CLASSROOM SYSTEM WITH PRIORITIZED PAGING
Full-Featured Green Mixer Amp Integrates Two Paging Priorities

AN-2133

Description:
Classroom mic, line and computer audio sources are connected to the HD‑MA35UA Mixer Amplifier through RDL wall plates. A school‑wide paging feed connects directly to the mixer amplifier paging input. The paging source may be either mic or line level. VOX switching eliminates the need for push‑to‑talk contacts. The HD‑MA35UA setup allows flexibility in muting or ducking the other input channels during paging. An ST‑VP2 Automatic Ducking Module adds an additional priority paging source. The ST‑VP2 uses the HD‑MA35UA effects loop to cause the highest priority page message to duck all other amplifier inputs to provide the emergency page. The ST‑VP2 is powered by the auxiliary module 24 Vdc power output from the HD‑MA35UA. The HD‑MA35UA powers up when audio is detected. When the system is inactive (no audio in use) it enters the sleep mode, consuming less than one watt for optimum energy conservation. The HD‑MA35UA returns to active mode (turns on) automatically when an audio input becomes present.

ELIMINATE AUDIO AND VIDEO HUM IN CLASS ROOM
Galvanic Isolation for Audio and Composite Video Ground Loops

AN-2101

Description:
Picture and sound quality from the player on the equipment cart is easily degraded by a ground loop. The difference in ground voltage between the audio/video source and monitoring locations can create herringbone or rolling hum bars in the video, and hum in the audio. Small ground loop voltages can easily impair the quality of audio and/or video signals. The RDL EZ‑HK3 removes the ground loop using a stereo pair of high quality audio and video transformers in a shielded metal enclosure. The input jacks are ground‑isolated. A ground‑lift switch allows the output jack shields to be lifted from the metal chassis if required.

AUTOMATIC POWERING OF CLASSROOM A/V SYSTEM
Automatically Turn System On and Off to Conserve Energy and Simplify Operation

AN-2104

Description:
The RDL FP‑ECC1 Energy Conservation Controller provides the capability to automatically power up the classroom A/V electronics when needed and to power down the equipment when not in use to conserve energy and reduce operating costs. FP‑ECC1 trigger input bridges the mic signal from the room to switch or hold the system on. Then the presence of line‑level computer audio at the FP‑ECC1 hold input also keeps the system powered. After a switch‑selectable time period of 15, 30, or 60 minutes of no use, the FP‑ECC1 will turn off the system electronics. No operator intervention is needed to begin or end use of the system. Audio and video inputs from the room are fed through RDL wall plates. The D‑ECR1L Power On/Off and Remote Level Control allows users to manually power up/down the equipment controlled by the FP‑ECC1 Controller and to adjust the audio output from the amplifier. The D‑ECR1L matches the style of the other wall plates.

PAGING DISTRIBUTION IN OFFICE COMPLEX
Common Paging for Multi-Story Office Building

AN-2108

Description:
Installed UTP (unshielded CAT5, CAT6 or similar) cable can be used to distribute facility‑wide paging to multiple floors or zones. The facility paging source for this multiple story building is fed to the RDL TX‑TPS1A Active Single Pair Sender. Its output is fed to a twisted pair receiver on one floor, then in turn to additional receivers on the other floors. All connections use UTP terminated with RJ45 plugs. A TX‑TPR1A Active Single Pair Receiver on each floor delivers line‑level paging audio to the local amplifier. Each Format A twisted pair receiver bridges the UTP cable, allowing the source signal to continue on to multiple receivers. The receivers are powered from the TX‑TPS1A sender. (Note: If the total distances between the receivers exceeds the recommended cable length for the cable type used, one or more additional power supplies may be required. If needed, an additional power supply may be connected to any of the receiver modules. Consult the Format‑A twisted pair data, or RDL technical support for more information.)

SINGLE ZONE AUTOMATIC PAGING LEVEL CONTROL
Automatic Stepped Level Adjustment for Ambient Level Changes

AN-2034

Description:
The circuit shown is ideal in applications where paging levels are normally sufficient, but at times high ambient noise levels make the paging impossible to hear. This is common in school hallways which may be empty or crowded, making higher sound system levels necessary during periods of heavy congestion. Normal levels are restored when traffic is minimal. In this example, the STP‑1 Universal Audio Attenuator is used to set two audio levels (normal and high) for the line‑level audio feeding the power amplifier for the hallway. A sensing microphone is oriented to pick up ambient noise but not paging audio. Ambient noise triggers the ST‑ACR1M which switches the higher audio input level to the amplifier. When noise levels return to normal, the ST‑ACR1M switches back to the standard paging level. An RDL TX‑70A Speaker Level Interface can be added to obtain line‑level paging audio from a constant voltage speaker line.

CLASSROOM WITH WALL-MOUNTED THREE-INPUT MIXER
Computer, Auxiliary Input, IR Receiver, Projector, Twisted Pair Audio Wiring, 20 Watt 70 or 100 Volt Audio Amplifier

AN-2043

Description:
This classroom is equipped with a computer and with jacks for an auxiliary audio/video source such as a DVD player or VCR. The computer is connected to a jack plate at the front of the room. The auxiliary input is shown at the rear. Audio from the audio/video input plates is connected to two inputs of a three input audio mixer located near the projector using twisted‑pair cable. The third mixer input is fed from the line‑level output of an IR receiver. (Note: A paging source could be connected to the third mixer input instead of the IR receiver, if desired.) The video is connected directly to the projector using coaxial and monitor cables. The projector audio output is not used. The mixer controls the level of each audio source using the associated wall mounted mixer remote control. The three knobs on the wall control provide separate audio level adjustment for the computer, auxiliary input and IR receiver. The audio power amplifier provides a 70 V and 100 V constant‑voltage output to power multiple speakers. The four speakers shown may each be tapped for 5 watts. All wall controls and panels are offered in RDL standard white/gray or in stainless steel with custom labeling available.

CLASSROOM WITH INTEGRATED MIXER AMPLIFIER
Simple Constant Voltage Classroom Sound System

AN-2137

Description:
The RDL HD‑MA35UA 35 Watt Mixer Amplifier is a full‑featured, four input mixer amplifier that can be readily desk mounted. The optional RDL HD‑BP1 Back‑Pack Rear Cover is designed to conceal and secure connections to the amplifier. When the system is not in use, the HD‑MA35UA enters sleep mode and consumes less that 1 Watt to effectively save power and reduce operating costs. The amplifier automatically turns back on (active mode) whenever audio is detected at any input. This classroom makes use of computer and DVD audio sources as well as a microphone. The HD‑MA35UA constant voltage (25 V, 70 V or 100 V) amplifier has sufficient power to enable proper loudspeaker distribution throughout the classroom allowing for even coverage and high intelligibility.

BASIC CLASSROOM W/ INTEGRATED MIXER AMPLIFIER ON AV CART
35 Watt Mixer Amplifier Powers Portable Classroom Audio System

AN-2131

Description:
This portable system provides robust amplification for portable speakers from multiple audio sources. Audio levels from a laptop computer, CD player and instructor's microphone can be independently adjusted on the HD‑MA35U, which also provides tone control to optimize audio for the room. The only active RDL component is the HD‑MA35U which powers up when audio is detected. When the system is inactive (no audio in use) it enters the sleep mode, consuming less than one watt for optimum energy conservation. The HD‑MA35U returns to active mode (turns on) automatically when an audio input becomes present.

CLASSROOM W/ PROJECTOR AUDIO/VIDEO SWITCHING
Computer, Auxiliary Input, Projector w/ variable output, 40 Watt Stereo Audio Amplifier

AN-2048

AMPLIFICATION FOR OUTDOOR POLE-MOUNT SPEAKERS
Pole Mounted Power Amp Operation in Extreme Temperatures

AN-2125

Description:
This outdoor parking area is equipped with speakers mounted in the lamp structures to provide music and paging coverage. Speakers in each pole are powered by an RDL FP‑PA18H 18 Watt Hi‑Temp Audio Amplifier. The amplifier module is mounted in an unventilated watertight enclosure at the base of each pole. The poles recieve direct sunlight causing the potential for high internal ambient air temperatures. The highly efficient FP‑PA18H is ideally suited to this environment. It is designed for operation in ambient temperatures up to 70 degrees Celsius (about 158 degrees Fahrenheit) and contributes negligible heat to the ambient temperature inside the pole. The amplifiers integral compressor/limiter insures maximum intelligibility by keeping average power levels high and preventing clipping. The FP‑PA18H combines RDL's high audio performance standards with the capability of operation in harsh temperature environments. Notes: 1] If it is desired to monitor the operation of the complete system, the audio detector included in each FP‑PA18H can be wired back to the system audio rack to confirm that audio is being received and amplified at each pole. 2] If the FP‑PA18H is acquired with an RDL power supply, that supply must be located in an ambient environment not to exceed 40 degress C. FP‑PA18H modules are available without a power supply for use with high temperature supplies or in systems using distributed 24 Vdc power. Contact RDL Technical Support for more information.

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