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The MLD9 MultiLoop™ Driver is a part of the new “benchmark range” for professional audio (AFILS) Hearing Loop systems. In the past, a Hearing Loop phased array system used to require two separate loop drivers and a 90° Phase Shifter which would take up valuable rack space. This elegant, sturdy unit features the most compact and most robust design on the market, *requiring only a single 19″ rack mount unit.

The MLD9 is capable of driving a wide variety of multiple loop configurations from multiple simple loops to phase shifted array or, low-spill systems for the most challenging requirements. With a MLD9 MultiLoop™ Driver and a Low Loss design or, a Low Spill design the MLD9 will provide an area of coverage 13,990 square feet or, can be used to drive two (2) Perimeter Loop areas of 35,520 square feet each with an unsurpassed clarity of sound for both music and speech for superior intelligibility. Based on proven and highly reliable technology it is backed by a 5 year warranty and Listen technical support. Improved power output provides outstanding value without compromise.

The MLD9 MultiLoop™ Driver boasts all the usual features such as (AGC) Automatic Gain Control which is optimized for speech with a Dynamic Range of >36 dB and (MLC) Metal Loss Correction. The MLD9 is a compact (1 RU) and elegant unit suitable for freestanding or rack mounting.

The MLD9 MultiLoop™ Driver provides a solution where a simple loop around the room perimeter will not work. Arrays are the standard solution for buildings with metal structure or reinforcements, or for covering large areas. Arrays can also dramatically decrease the _„ƒspill’ of the magnetic signal outside of the room, allowing hearing loops to be installed in adjacent rooms and providing an improved level of confidentiality. Arrays can also be used to change the way two loops interfere with each other, providing ways of solving even the most complex installation problems.


One (1) MLD9 MultiLoop™ Driver
One (1) 1U 19″ Rack Mount (brackets included)
One (1) Handbook and installation instructions
One (1) T-Coil Loop System present Sign (deaf logo)
Two (2) Neutrik NL4 output connectors for each output
One (1) Region specific IEC power cable
One (1) Status and DC Connectors


  • Coverage area up to 13,990 sq. ft. for a Phased /Low Spill Array or, (2) Perimeter Loop areas of 35,520 sq. ft. each
  • Drives two (2) output channels at 9.2 A (RMS) each, featuring selectable accurate and stable 90° phase shift
  • Even field strength and frequency response in the presence of metal structures
  • Even field strength over very large areas
  • Reduced spill to 3-6 ft. (1-2 m) from the loop edge for adjacent rooms or confidentiality
  • Minimizes interactions between complex systems such as theaters and balconies
  • Low lifetime cost
  • Excellent proven reliability
  • 5 year warranty
  • Unparalleled sound quality and intelligibility
  • Speech optimized (AGC) Automatic Gain Control with a Dynamic Range of >36 dB
  • High voltage headroom avoids high frequency clipping
  • (MLC) Metal Loss Correction corrects frequency dependent loss from metal structures
  • Rack mount brackets included
  • Two inputs, microphone (XLR) and switchable between Mic and Line inputs
  • XLR inputs have switchable 15 dB gain boost between microphone and line on the rear panel
  • Selectable 12V phantom power on microphone only
  • Extensive input adaptors available for any audio input requirements
  • Loop connectors are Neutrik NL4 Speakons (supplied), one for *each output
Configurations & Architectural Specs


MLD9 MultiLoop™ Driver

Architectural Specs

The MultiLoop driver shall continuously deliver two (2) x 9.2 A(RMS) per channel when excited with a 1 kHz sine wave as measured with the IEC 62489-1 induction loop amplifier performance standard. Only drivers that have been tested and compliant to this IEC 62489-1 specification shall be accepted, no other substitutions will be allowed.

In a Perimeter Loop application it shall cover up to two (2) x 13,990sq. ft. (1,300 m‘_) each. In a MultiLoop Low Loss or, Low Spill Phased Array application it shall cover up to 35,520 sq. ft. (3,300 m‘_). The MultiLoop driver shall internally incorporate two (2) loop drivers and one (1) SP5 90° audio phase shifter. The MultiLoop driver with the proper design shall have reduced spill to no more than 1.5 ft. (1 m). The MultiLoop driver shall have a frequency response of at least 80Hz to 6.5kHz +/- 3 dB with THD+N less than 0.2%.The unit shall incorporate (AGC) Audio Gain Control optimized for speech with a compression dynamic range of >36 dB audio processing. The unit shall incorporate Metal Loss Correction to rectify frequency loss caused adjacent metal structures. The unit shall occupy one rack space and rack mount brackets shall be included. The MultiLoop driver is tested to and compliant with: IEC 62489-1 induction loop amplifier performance standard.

The MLD9 MultiLoop™ Driver (9.0A) is specified.


Qualification and Certification of the Contractor
Only AV Integration Firms/Dealers that have completed and are currently certified under specific manufacturer training to test, install, and commission along with providing a Certificate of Conformity in accordance with the IEC 60118-4 standard shall be eligible to bid upon this portion of this bid.

Product Specifications


Frequency Response80 Hz to 6.5 kHz ±3 dB
DistortionTHD+N < 0.2 %, 1 kHz Sine Wave at Full Current
AGCOptimized for Speech, Dynamic Range > 36 dB
Line Input1/4 in. (6.4 mm), -30 dBu Input, Overload Protected


Gain ControlFront recessed input level control
Metal Loss CorrectionCorrect system frequency response due to metal structures
CoolingTwin variable speed fan cooled. Front inlet, reat exhaust


Drive Current Indication6-LED Display Front Panel, 2 dB Increments
Fault MonitoringLED Fault Indicators, Overload, Overhead, Loop Error
Remote Fault MonitoringRelay Contacts


Microphone/Line InputTwo (2) - XLR Mic or Line Switchable, Mic - sensitivity -55dBu, 200-600 Ohms, +12 VDC Phantom Power, Line - sensitivity -30dBu
Slave I/O1/4 in. (6.4 mm), Insert Point for SP5 90° Audio Phase Shifter, 0 dBu
Loop Connector/sNeutrik NL4 Speakon
Loop Monitor Connection3.5 mm stereo headphone connector - Channel A on Left, Channel B on Right
Ancillary± 15 VDC, 0.15 A, Power Outlet to Power Accessories


Loss Control Phased Array - CoverageNo Metal: 35,520 sqft. (3,300 m²)Moderate Metal Loss: 9,956 sqft. (925 m²)High Metal Loss: 4,575 sqft. (425 m²)
Low Spill Phased Array - CoverageNo Metal: 13,185 sqft. (1,225 m²)Moderate Metal Loss: 7,535 sqft. (700 m²)High Metal Loss: 3,498 sqft. (325 m²)


ComplianceETL Listed
Power230/120 VAC, 220 W, 45-65 Hz, Power Switch/Led (Hearing Loop Logo) on Front Panel
Drive Voltage31.8 V (RMS) at Maximum Output Current
Drive Current9.2 A (RMS), 13.0 A (Peak) with 1 kHz Sine Wave
Drive Current Peaks4.6 A (RMS), Short Term > 19 A


Width8.7 in. (220 mm)
Height16.9 in. (430 mm)
Depth1.7 in. (44 mm)
Shipping Weight17.0 lbs. (7.71 kg)
MountingFreestanding or Rack Mounted
Weight14.0 lbs. (6.35 kg)


Relative HumidityIP20 Protection, 20 to 90% Relative Humidity, 32 F (0 C) to 95 F (35 C)
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