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Microphone SNR Booster

Based on measurements of a microphone’s free-field response and its acoustic and electronic noise limits, Illusonic’s SNR Booster technology increases the practically effective SNR by up to 10 dB.

SNR improvement
up to 10 dB
Microphone capsule type
omni or pressure gradient
Algorithmic Delay
2 to 10 ms

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Microphone Beamformer

Illusonic’s patented acoustic “beam-shaping” technology simulates a virtual higher order directive microphone based on at least two first order microphone capsules. The directivity of the simulated microphone’s signal is higher than that of any real microphone, while maintaining high signal fidelity.

SNR improvement
up to 10 dB
Microphone capsule type
omni or pressure gradient
Algorithmic Delay
2 to 10 ms
Algorithmic Delay
2 to 10 ms

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Stereo Microphone Post-Processing

Signals of conventional stereo microphones are post-processed to modify the width of the stereo image and spaciousness, without using any delays or artifical reverberation. This enables flexibility otherwise only known from B-format microphones.

Directivity Index (DI) modification
0 to 6 dB
Diffuse gain control
-12 to 12 dB
Microphone type
Stereo coincident
Microphone capsule type
Cardioid, super-cardioid
Algorithmic delay
4 to 10 ms

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Surround Based on Two Microphones

The signals of conventional stereo microphones are processed to simulate five virtual microphones to generate a discrete 5.1 surround audio signal.

Surround format
5.1
Directivity Index (DI)
4.7 to 16 dB
Diffuse gain control
-12 to 12 dB
LFE filter
60 to 120 Hz, order 2 to 4
Array type
Stereo coincident
Microphone type
Cardioid, super-cardioid
Algorithmic delay
4 to 10 ms

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Surround Based on Three Microphones

The signals of three coincident or nearly coincident microphones are processed to simulate N virtual microphones to generate a discrete N.1 surround audio signal.

Surround format
5.1, 7.1, N.1
Directivity Index (DI)
4.8 to 16 dB
Diffuse gain control
-12 to 12 dB
Rotate
360 degree
LFE filter
60 to 120 Hz, order 2 to 4
Array type
coincident
Microphone type
cardioid
Algorithmic delay
4 to 10 ms

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Acoustic Feedback Control

Based on an estimate of the acoustic feedback transfer function, an equalizer is controlled to prevent feedback and allow higher gains. Fullband gain control prevents instability even in extreme conditions.

Convergence time
50 to 200 ms
EQ range
-20 to 0 dB
Gain range
-20 to 0 dB
Algorithmic delay
0 to 8 ms

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Upmix

Time-frequency signal analysis, spatial hearing modeling, auditory filterbanks, and spatial synthesis processing convert stereo signals to discrete-like 5.1, 7.1, and 3D surround. Additionally, matrix surround stereo signals (Lt, Rt) are converted to discrete-like surround with a 360 degree spatial image. High channel separation enables discrete-like quality and unproblematic re-downmix to stereo. This technology enables high-quality and cost effective upgrade of stereo content and services to surround.

Input format
stereo, 5.1, 7.1, etc.
Ouput format
5.1, 7.1, 3D
Upmix modes
normal, matrix, auto
Stage width
60 to 360 degrees
Channel separation
up to 40 dB
LFE filter
60 to 120 Hz, order 2 to 4
Algorithmic delay
4 to 10 ms

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Downmix

Supports ITU and matrix compatible downmixing. Unique features, such as ambience level control in the downmix and active matrix downmixing, provide a new level of control. A special mode optimized for Illusonic Upmix enables a high quality 5-2-5 chain.

Input format
5.1
Output format
ITU, Lt/Rt
Ambience control
-6 to 0 dB
Active downmix
On/Off
Algorithmic delay
2 to 10 ms