Forum™ Receiver Amplifier

PN: IMA-240

Amplifier | Infrared Microphone Receiver | Audio Mixer








Forum™ Receiver Amplifier Description

The TeachLogic Forum™ instructional audio system provides the classroom with a platform to clearly deliver all audio sources so that learning happens regardless of where the students are located.  This versatile system supports 2 infrared wireless microphones, 3 classroom audio sources like a computer or TV, and 2 audio outputs for assistive listening system connection, lesson capture recording, and/or video conferencing to support hybrid learning models.

In addition to these must-have features, the internal architecture of the Forum™ includes a Digital Feedback Guard (DFG) to suppress unwanted noise, a Computer Anti-Hum Circuit to eliminate those pesky low level humming sounds computers can make, and a USB charger for convent placement of and access to the microphone charger.

A 4th audio source can be added by using the IRT-66 Mobile Display Transmitter. Now you can easily roll in a portable audiovisual cart to any classroom and instantly connect to the Forum’s speakers. No additional wires needed.

Why IR?

Forum™ Receiver Amplifier Details


  • Amplifier: digital hybrid class D
  • Two Power Amplifiers: 25 watts ea. channel, total 50 watts RMS for 4 x 8Ω loudspeakers
  • 3 Line Level Inputs, mixed w/ the two microphone inputs
  • 2 Line Level Outputs
    • Rear panel mixed output for assistive listening system and/or lesson capture with gain control (3.5mm)
  • Hybrid Learning Compatible
    • Front panel input & output connects to host computer to synchronize classroom audio w/ video conference application
  • Digital Feedback Guard™
  • Switchable computer anti-hum circuit with ON/OFF switch
  • 3-band digital equalizer ± 10dB
  • Power sleep mode to conserve energy
  • Light weight aluminum cover
  • Teacher Priority function attenuates volume of all line inputs with button press
  • Drop-in microphone charger connection 5 VDC USB
  • Accommodates up to 3 ceiling sensors for increased microphone reception coverage and/or extra-large classrooms
  • WC-400 Wall Mounted Cabinet (optional)
  • Rack or shelf/wall mounting kits (optional)


Weight 1.56 lbs
Dimensions 7.5 × 8.5 × 1.75 in
Receiver Input

Infrared FM


FM Wide-band

Reception Frequencies

Ch. A: 2.08 MHz, Ch. B: 2.54 MHz

Infrared Wavelength


Tone Signal

Ch. A: 32.768 kHz


50 μs

Frequency Response

40 Hz –18 kHz, ± 3 dB

S/N Ratio

›65 dB


‹1% @1 kHz

Nominal Deviation

±10 kHz

Maximum Deviation

±25 kHz

External Sensor Input

Two, RCA

Connectivity Coverage

1,600 Sq. Ft., 50 ft. line of sight

Aux Inputs

One DVD, Line Level, Dual RCA with +10 dB Gain Control
One Aux input with front and rear panel 3.5 mm

Line Output

Two 3.5 mm with Gain Control, Front Panel


Three-band digital ±12 dB

Output Power

Total (RMS), 25 watts ea. Two digital Amplifiers, 50 Watts

Output Impedance

4 Ω min.

Output Connection

One 4pin Phoenix Connector

Power Supply

19 VDC / 3.4 A CE,CSA and UL Listed

Forum™ Receiver Amplifier Components

Classroom Component Layout

  • Sapphire (IRT-60) wireless pendant transmitter, a high-quality cardiod microphone with lanyard.
  • ICS-55 Ceiling Sensor gives 360-degree infrared coverage for optimal audio performance.
  • Forum™ 232 Sound Field amplifier/receiver to support classroom audio sources.
  • SP-628 Ceiling Speakers (four shown) provide excellent quality voice reproduction.
  • SP-2000 Wall Mount Speakers (optional), allow for installation when ceiling is not accessible.

Forum™ Receiver Amplifier Downloads