1. How ClearOne Microphone Technology Improves Speech Recognition Results SpeechTEK 2007 Kurt Olsen Director of Product Marketing ClearOne

2. ©2007 ClearOne Communications. Confidential and proprietary. Topics +Why the microphone is so important in speech recognition +ClearOne audio devices: Chat 50 & Chat 150 +ClearOne microphone technologies >Mic pickup patterns >Noise cancellation >Automatic level controls >Echo cancellation

3. ©2007 ClearOne Communications. Confidential and proprietary. Why the microphone is so important in the speech recognition equation

4. ©2007 ClearOne Communications. Confidential and proprietary. The challenge “Hello” Low volume level Human hearing

5. ©2007 ClearOne Communications. Confidential and proprietary. The challenge “Hello” Low volume level Human hearing

6. ©2007 ClearOne Communications. Confidential and proprietary. The challenge “Hello” Low volume level Speech recognition

7. ©2007 ClearOne Communications. Confidential and proprietary. The solution: ClearOne audio devices Chat 50 & Chat 150

8. ©2007 ClearOne Communications. Confidential and proprietary. Chat 50 +What is it?Multi-use personal speaker phone with microphone, speaker, volume & mute buttons +What does it connect to?PCs & Macs Cell phones Telephones

9. ©2007 ClearOne Communications. Confidential and proprietary. Chat 50 +FeaturesFull duplex audio (two-way) Rich audio with full bandwidth frequency response (20Hz – 20kHz) Echo cancellation Noise cancellation Automatic level controls

10. ©2007 ClearOne Communications. Confidential and proprietary. Chat 150 +What is it?Multi-use group speaker phone with 3 microphones, larger speaker, volume controls +What does it connect to?PCs, enterprise telephones, video conferencing systems

11. ©2007 ClearOne Communications. Confidential and proprietary. Chat 150 +FeaturesFull duplex audio (two-way) Rich audio with full bandwidth frequency response (20Hz – 20kHz) Echo cancellation Noise cancellation Automatic level controls Automatic microphone gating technology

12. ©2007 ClearOne Communications. Confidential and proprietary. ClearOne microphone technologies: mic pickup patterns +Directional pickup pattern >Makes speech clearer by removing unwanted noises coming from sources around the talker >Also attenuates (reduces) reflections in the room, eliminating the “bottom of the barrel” effect >Goal: deliver an audio waveform that only contains speech – improves speech recognition results +Chat 150 – has automatic microphone gating techniques Cardioid microphone 120-degree pickup pattern

13. ©2007 ClearOne Communications. Confidential and proprietary. ClearOne microphone technologies: noise cancellation +Removes ambient (constant) background noises >Air conditioner >Projector fan >PC fan >Fluorescent light hum +Detects constant state of noise, digitally removes from the outgoing audio stream +Increases the speech-to-noise ratio >How loud is my speech level compared to my noise ratio >The bigger the gap, the cleaner audio, and better speech recognition results Noise floor level Speech level

14. ©2007 ClearOne Communications. Confidential and proprietary. ClearOne microphone technologies: automatic level controls +Automatic level control >Adjusts loudspeaker volume up for soft talkers >Adjusts loudspeaker volume down for loud talkers +Automatic gain control >Adjusts microphone level up for soft talker >Adjusts microphone level up as distance increases between mic & talker >Adjusts microphone level down if too loud +Goal is to deliver intelligible audio that is loud enough to be understood by far-end listener or speech recognition engine

15. ©2007 ClearOne Communications. Confidential and proprietary. ClearOne microphone technologies: echo cancellation +Echo: >Outgoing audio is returned back to the listener >For open-air, two-way communications, echo cancellation is essential >Most devices just suppress outgoing or incoming audio -Half-duplex – very difficult to carry out a meaningful conversation +ClearOne is a pioneer and industry leader in full-duplex performance with excellent echo cancellation technology +Speech recognition: audio bursts from PC (e-mail chimes, etc.) can result in interruption to speech audio and false recognition results +Our technology eliminates this problem – only audio coming into microphones from local room gets passed through, not audio from speakers

16. ©2007 ClearOne Communications. Confidential and proprietary. The bottom line +ClearOne’s advanced audio processing technologies deliver crystal-clear audio for audio conferencing applications, and also for speech recognition applications +Result: better translation of audio streams by speech recognition engines