LEAN AUDIO No.1 for PA Loudspeakers, Guitar Speakers, Bass Guitar Speakers & HI FI speakers

Linea Research 44M20 Amplifier 20000 watt 4 x 5000 watts RMS minimum 2 ohms



Linea Research 44M20 20000 watt Power Amplifier with integrated DSP


Four channels
20kW total power output
Control, monitoring & alarm: Ethernet, configurable function Volt-free relay and contact closure port.
Energy saving modes: Standby and deep ECO sleep both with auto-sleep timers.
System sleep and wakeup: Front panel switch, network command, contact closure. and audio detection.
Max ambient temperature (full power, no audio limiting) 40degC (105degF)


Amplifier topology: Proprietary 5th generation Linea Research Class D.
Amplifier modulation scheme: Low feedback, multiple loop, with feedforward error correction.

Output Power for 44M20

Output power per channel all channels driven with continuous program material

5,000W RMS into 2Ω at a crest factor of 4 (12dB)
2,600W RMS into 4Ω at a crest factor of 2.8 (9dB)
1,300W RMS into 8Ω at a crest factor of 2 (6dB)


10,000W RMS into 4Ω at a crest factor of 4 (12dB)

Output power per channel, all channels driven with continuous program material at a crest factor of 4 (12dB) 3,500W RMS Hi-Z, 70V line. 5,000W RMS Hi-Z, 100V line

Audio Performance

Dynamic range (analog input to speaker output): >113dBA typ.
Dynamic range (AES3 or Dante input to speaker output): >114dBA typ.
Frequency response: +/- 0.5dB, 5Hz to 20kHz, 4 Ohms. / -2.5dB, <3Hz to >30kHz, 4 Ohms.
Total harmonic distortion, THD: <0.05% typ, 1kHz, AES17, 4 Ohms.
Inter-channel crosstalk (worst combination of channels): better than -85dBr at 1kHz. / better than -75dBr at 10kHz.
Maximum analog input level: +20dBu.
Analog input sensitivity range for full output: 0dBu to +20dBu, continuously adjustable.
Analog input: 20k Ohm, electronically balanced. Analog link: Directly connected to the analog input.
Analog ground scheme: AES48 standard compliant.
AES3 input: Transformer isolated with active cable equalisation for extended range (unique to Linea).
AES3 link: Active AES3 signal regeneration with automatic direct bypass to the AES3 input if the unit is unpowered.
AES3 supported sampling rates 24kHz to 192kHz (auto locking).

Digital processing

Resolution: 40 bit, using proprietary LMD (Linea-Micro-Detail) algorithms.
Sample rate: 96kHz throughout.
Class leading limiter suite : See the ‘speaker protection systems’ section.
Hardman crossover filters: Better out of band rejection than Linkwitz-Riley (Unique to Linea).
LIR crossover filters: Linear Phase without the compromises of FIR filters (Unique to Linea).
FIR Shelving EQ filters: For linear phase filtering.
Overlays: Twelve additional independent overlays of EQ, Delay and Gain

Power Supply

Topology (main power supply): 3rd generation Series Resonant.
Topology (auxiliary and standby supplies): Low quiescent Eco-Flyback.
Internally stored energy: >600 Joules. Mains input voltage range (automatically configured): 85V to 240V.
Mains input frequency range: 47Hz to 63Hz.
Mains inrush current (max for <10ms): 6A at 115V, 12A at 230V.

Protection systems

Note : Under all circumstances the control and protection systems will endeavour to deliver the maximum power possible for a given set of conditions, applying limiters only in extreme circumstances. Muting will only occur when a dangerous situation is detected, normal operation automatically resuming when the condition clears.

System protection

Excessive output current
Excessive power supply current
Excessive amplifier section temperature
Excessive power supply section temperature
Excessive DSP section temperature
Mains voltage out of range
Fan speeds out of range Internal power rails out of range

Speaker protection

Audio soft-clip limiter
VxLim, Multiband peak limiter (Unique to Linea)
VxMax, Multiband overshoot limiter (Unique to Linea)
Vx-Xmax, Driver excursion limiter
Vx-Tmax, Driver thermal limiter (long term power limiter)
DC offset protection Excessive HF energy (VHF) limiter

Power distribution protection systems

Mains inrush current limiting (soft start and anti-surge).
Mains average current limiting (mains breaker / fuse trip protection).
Randomised initialisation when remotely commanded to power up

Monitoring and logging

Supply current logged vs time
Supply voltage logged vs time
Thermal Capacity logged vs time
Each driver current logged vs time
Each driver impedance logged vs time
Protection limiting for each output logged vs time
Number of power cycles counted
Number of mains brownout events counted Fan speeds continuously monitored
Fan underspeed events counted
Various protection mute events counted
Driver Impedance continuously monitored

An inbuilt alarm and notification system can be configured to indicate problems to remote devices either via the network or the Volt-free changeover relay contacts accessibly on the rear panel.


Cooling: Two variable speed fans.
Airflow: Front to back.
Air filtration: Washable media, changeable without the use of tools
Analog IN and LINK connectors: Genuine Neutrik XLR.
AES3 IN and LINK connectors: Genuine Neutrik XLR.
Audio output connector: Genuine Neutrik Speakon.
Mains input connector: Genuine Neutrik 32A Powercon.
Dante Primary and Secondary: Shielded RJ45.
Relay output & contact closure inputs: Phoenix pluggable terminal block.
Front panel display (backlit): Graphical, high contrast, daylight visible.
Front panel encoders: Two, indented, velocity sensitive.
Front panel push buttons: Large, tactile, illuminated.
LED indicators: Bright, easily differentiated.

Enclosure: Standard 19” 2U (88mm) with handles and optional rear support system
Depth (behind rack ears): 357mm (14”).
Net Weight: 12.5kg (27.5 pounds).

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