microphone array designed for long range audio surveillance

Listen conversations from a distance without anyone to notice your device


X64ACS is a handheld long range highly directional microphone surveillance system. This type directional microphone is based on a fixed phased array technology or also called acoustic radar, specially designed for the execution of a single task - collecting of human voice audio information in real
time for complex situations.
64 channel fixed phased array is used to create an acoustic antenna with a more desirable form factor than the conventional parabolic reflector or cassegrain reflector. Same principle of beamforming and amplification is today used in radar systems.
This technology allows receiving conversation to 150 meters. Range exceeds 200 meters if there is no strong presence of ambient noise.

Enhanced directional response of
the microphone array

Transition from flat to complex surface

To achieve even better performance with bigger Signal to Noise Ratio [SNR] the construction of X64ACS array is flat only for the absolutely perpendicular wavefront of the incoming audio signal. This is achieved by mechanical realisation of a so called acoustic tiered-retardant series.

Eliminated noise from mechanical vibrations

The case in which the microphone is situated is designed to serve as a shock absorber, and prevents any vibration generated noise to be transferred to the active surface of the directional microphone.

Dynamic camouflage that works

The attachment of the front part of the phased array is flat elastic system, ensuring both firmly fixed directional microphone to the bag and no impact to the front of the incoming sound wave. The rear panel of the laptop bag is sound-conductive fabric indistinguishable from standard unmodified one.

X64ACS enhanced directional microphone phased array

Covert surveillance microphone that can spy even on a moving target

Stay invisible and listen everywhere

Entire directional microphone is placed in a specially modified laptop case, indistinguishable from the original one.

Hear most distant conversations

Using 64 channel acoustical phased grid gives you all the amplification you need for detailed audio surveillance. No need to worry about hiding parabolic reflector anymore.

Pickup talk while carrying it along

Carrying a laptop bag over your shoulder, you can hear the conversation of interest without raising the slightest suspicion in nearby passers.

Undisturbed listening in case of sudden noises

The perfect combination of soft compressor, human voice bandpass filter, AMPFLAB smart automatic gain control system gives you comfort and protects your ears without loosing dynamics of the sound.

Simple to use hidden control panel

Management of the amplifier, headphone output and output for recording device are located in the outer pocket of the bag, again camouflaged and indistinguishable to the observer.

Listen with audiophile quality

Directional microphone with powerfull Class A Di-Fet headphone amplifier powered by 24 volts. The amplifier is based on OPA627, that many consider to be one of the best audio chips available.

Be everywhere and do not miss an important moment

24 volts rechargeable Li-Ion battery pack.
Go operational for 22 hours continuous work without worrying about charging or replacing batteries. Power pack that turns your directional microphone in a stand-alone surveillance system.

Remove with one click unnecessary sounds

Second order active bandpass filter designed to amplify human voice frequency range. Eliminate with just one switch all unwanted ambient sounds. Enjoy hearing amplified from a long range conversation without disturbing sounds.

Visually fully standard laptop case

Mass fabricated widely available 17 inch laptop bag which is fully identical to the original one from the outside.


The name of the microphone – X64ACS itself represents the basic principle of work. Incoming audio signals are processed or multiplyed [X] with [64] acoustical [A] chanels [C] which are separated [S].

Microphone based on a fixed phased array has inherently directional nature, because the amount of audio signal seen by the apperture varies with the direction of the arrival. The term phased reffers to the time of arriving of the signal to the acoustic chanel, and array is actually multiple elements sharing one and the same flat linear surface. Used for X64ACS array is contructed by 64 independent acoustic channels, which are interconnected by a phase channels, providing sound processing.

If the front wave of the incoming sound signals is unidirectional they arrive at one and the same time to all 64 channels of the directional microphone array. Arriving of signal at one and the same time means that all of the received components of the sound are in phase and will be summed and thus amplified. When sound waves come from direction which is not perpendicular to the face of the directional microphone array the time of the received signals is different in all 64 channels. That means signals are out of phase and they will cancel each other out – phase cancellation or destructive interference. The biggest angle is, the lower is signal.

As it can be seen on the scheme, the time of arriving of the front wave (t1.1 ... t1.4) is equal, while time of arriving of a nonunidirectional wave (t2.1 ... t2.4) is completely different, and thus they it will be rejected.

directional microphone fixed phased array shematic

Camouflaged tactical directional microphone


When it comes to surveillance equipment


Fast adaptive Class A Headphone amplifier designed and built to meet the requirements of changing tactical situations and varying environmental noises.

Using directional microphone for audio surveillance in urban areas usually requires extremely short response time for the operator.
Achieve your objective using AGC system with momentary response and no distortion. System that cannot be fooled by surrounding noises.
Simple to use control panel operated in a seconds gives you tactical advantage in a places crowded with people.

headphone amplifier for long range directional microphone

Basic features of the X64ACS audio amplifier

Basic features of the X64ACS audio amplifier

Huge amount of headphone power delivered by
pure Class A amplifier

Headphone power amplifier built to hear even the subtlest nuances from the targeted area. Designed to amplify every detail crystal clear, using precision FET operational amplifier with new level of performance - Burr Brown OPA627.
Precision High-SpeedDifet® Operational amplifier that offers lower noise, lower offset voltage and higher speed. Amplifier that extracts more detail from complex mixed sounds, where human voices sound realistic and had their own space around them.

Switchable human speech bandpass filter

Active second order bandpass filter that rejects all noises which are not in the human voice frequency band.
The Frequency spectrum that goes through this filter is from 300Hz to 4500Hz. Additional option to switch On or Off the filter gives you more flexibility of the device.
For example - switch off the filter if you want to record wild animals from far away. Switch it on if you use the directional microphone in urban area with lots of background noises and simply want to hear someone's conversation.

Automatic Gain Control

Performing audio surveillance outdoor using directional microphone as a primary tool takes you in a very complicated acoustic scene.
The primary use of Automatic Gain Control (AGC) is to tame the substantial variations in signal levels encountered with speech or other usefull source of sound. The goal of the AGC is to provide comfortable listening while move the signal level closer to the ideal Target level without eliminating the natural dynamics of the signal.
The X64ACS AGC system is free for the operator - you can set your own threshold level, and while you set it your ears will always be protected from dangerous sound levels.