Fig.1. Scheme of modules GritTec's Combo-SpeechEnhancer

   GritTec's Combo-SpeechEnhancer is complex using of technologies DMA and NC allows at first by means of DMA to suppress all external hindrances and background noises in a direction of the chosen speech source, and then by means of NC to suppress all remained external noises and absent-minded hindrances what DMA could not suppress completely. The sources of external hindrances can be an external noise of car, speech of collocutor, music and any other sounds, coming from directions, different from direction of the chosen source of the speech.
   The made updating in MC allowed to receive on an output of the dual microphone array the clear speech with lower speech distortions and higher suppression of external hindrances and noises. This result was possible to reach at the expense of work optimization of the adaptive filters which used in module MC.
   Also this updating in MC automatically allows expanding quantity of adaptive filters for suppression of other external hindrances and suppression of an acoustic echo. At the moment experiments on suppression of other external hindrances and an acoustic echo are not finished yet.

General features of GritTec’s Combo-SpeechEnhancer (ver.1,0):

• Support of 1 or 2 microphones configurations;
• Configurations: DMA&NC, DMA or NC;
• Delay of the algorithm: 8 ms;
• Noise suppression not less 25 db (for DMA&NC);
• High quality of speech enhancement.

• Support of 2 microphones configurations;
• Delay of the algorithm: 8 ms;
• Directional microphones: unidirectional configuration (omni-uni directional);
• Distance between microphones not less 0.04 meters;
• Distance to the speaker not less 0.5 meters (up to 5 meters (?));
• Choice of a direction of a speech source: hand control;
• Noise suppression not less 15 db;
• Low level of speech distortion.

• initial signal from 1st microphone ;
• previous version DMA(ver.1,21) ;
• new version DMA(ver.1.3) ;
• DMA(ver.1.3) and NC ;
• suppresion with NC .